630.7 I6b no. 685 cop. 8 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN AGRICULTURE AGRICULTURE LIBRARY Characterization of TOMATO VARIETIES AND STRAINS For Constituents of Fruit Quality A. E. Thompson, R. W. Hepler, R. L Lower, and J. P. McCollum \- Bulletin 685 UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION CONTENTS MATERIALS AND METHODS 4 DISCUSSION OF RESULTS 10 Four measurements of fruit color 10 Three measurements of cracking 15 Measurement of firmness of flesh 17 Measurement of pH, total titratable acidity, soluble and total solids, and fruit weight 20 Holding capacity of fruits on the vine 25 Factors affecting breakage induced by dropping fruit 27 Summary of varieties or strains recommended for additional research 30 SUMMARY 31 LITERATURE CITED . ..32 Urbana, Illinois April, 1962 Publications in the Bulletin series report the results of investigations made or sponsored by the Experiment Station Characterization of Tomato Varieties and Strains for Constituents of Fruit Quality A. E. THOMPSON, R. W. HEPLER, R. L. LOWER, and J. P. McCoLLUM 1 Very limited improvement of tomato fruit quality can be accomplished by selection based upon visual observation. For this reason research has been conducted at the Illinois Agricultural Experiment Station since 1945 on the development of rapid, objective breeding methods and tech- niques for the measurement and identification of fruit quality factors ( 1 , 3, 6, 7, 8, 9, 10, 11, 12). 2 The need for such research has been accentu- ated by the rapid development of the mechanical tomato harvester. Such factors as resistance to cracking, firmness of flesh, and ability to withstand handling, take on increased importance in view of the impend- ing technological changes. The ability of a variety to hold ripened fruit on the plant for a long period of time so that higher yields can be obtained in a once-over harvest is also important. However, as fruits ripen, the pH generally increases and the total titratable acidity decreases. Such decreases in acidity undoubtedly will increase the loss of processed products through spoilage, commonly called "flat sour." Such spoilage is caused by the germination of certain thermo- phyllic bacterial spores not killed by the heating process or not held in check by an adequate level of acidity. Therefore, higher levels of acidity than are normally found in tomato varieties would be highly desirable. Higher levels of citric acid, which constitute a large portion of the titrat- able acidity in the tomato fruit, may necessitate a proportional increase in sugars to balance the flavor of the fruits and processed products. ^ Color is considered one of the most important characteristics of tomato fruit quality. The inadequacy of selection by visual methods becomes apparent when it is realized that color depends upon both the content of total carotenoids and the ratio of lycopene to carotene. Genetic variation in tomato fruit color is known to exist, but the separation of heritable from environmental effects is extremely difficult unless adequate sampling and testing techniques are employed. McCollum (11) thoroughly discussed the problem of sampling tomato fruits for composition studies. He pointed out that where the constituents of quality are dependent upon so many factors such as maturity, light 1 This bulletin was prepared by A. E. Thompson, Associate Professor of Vegetable Crops; R. L. Lower, Research Assistant in Vegetable Crops; and J. P. McCollum. Professor of Vegetable Crops, all of the Department of Horticulture; and R. W. Hepler, formerly Assistant Professor of Vegetable Crops, Department of Horticulture, and now Geneticist, California Packing Corporation, San Leandro, California. 2 Numbers in parentheses refer to literature cited. 4 BULLETIN No. 685 [April, exposure and accompanying temperatures, morphological structure, posi- tion on the plant, and season of development, differences between prog- enies or treatments are difficult to measure without the utmost care in sampling. Before an effective breeding program can be initiated for any charac- teristic, it is always desirable to determine the nature and extent of varia- tion existing in available varieties and breeding lines. Widely scattered references regarding measurement of some of the constituents of fruit quality on certain varieties or strains are available in the literature. Assem- bling these data for comparative purposes, however, would be of little value since the environmental conditions under which the plants were grown would vary greatly, and the sampling and measurement methods would not be adequate in most instances. The primary objectives of this study were to measure under compar- able conditions the various constituents of fruit quality on a selected col- lection of standard varieties and breeding lines or strains, and to demonstrate the feasibility of utilizing available techniques in a practical plant breeding program. This was to be accomplished by using the most appropriate methods of analysis and measurement, and a standardized procedure of sampling. The data collected would help define the extent of variability and thereby characterize the various varieties and lines as possible sources for future tomato breeding research. The utilization of these data and the adoption of these techniques by plant breeders would have the effect of placing the improvement of the tomato on a firm scientific basis. MATERIALS AND METHODS An attempt was made to assemble and evaluate varieties and breeding lines upon which selection had been practiced with regard to the con- stituents of fruit quality. A total of 21 were selected for inclusion in the replicated experiment. Table 1 lists the source of seed, and Table 2 lists the reasons individual varieties or strains were included. The plants were set in the field at the Vegetable Crops Research Farm at Urbana on May 24, 1961, by means of a single-row transplanter. The experimental design was a randomized complete block with two replications, and plots of 30 plants. The large number of plants per plot was used to assure the selection of a uniform sample. The spacing was 5 feet between and 3 feet within the rows. Standard fertility, cultural, and disease and insect control practices were followed. Table 3 gives a summary of the temperatures and rainfall for the 1961 growing season. The temperature averaged approximately 2 degrees below and the rainfall approximately 2 inches above the 1903-1954 mean for this period of time at Urbana. 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS Table 1. Varieties and Strains Tested and Source of Seed Variety or strain Number of j-. Pedigree generations number, selfed and Source of seed received if selected at Illinois 1252 (Y 13 X Garden 111. Agr. Exp. Sta., State 8 ) F 7 Urbana 1483 (Ace. 326 X 111. Agr. Exp. Sta., Garden State 3 ) F Urbana Garden State 1944 17 Campbell Soup Co., Riverton, N. J. Y 13 1953 Y 13-MDS2 8 Campbell Soup Co., West Chicago, 111. Y 112 1956 Y 112-MFS2 5 Campbell Soup Co., West Chicago, 111. Y 206 1956 Y 206-MCS1 5 Campbell Soup Co., West Chicago, 111. Kc 109 1957 Kc 109-J10 6 Campbell Soup Co., Riverton, N. J. Kc 146 1957 Kc 146-E19 6 Campbell Soup Co., Riverton, N. J. HRS 193 1960 HRS 193-8-2-2-C 2 W. Shumovich, Ont. Agr. Res. Sta., Harrow, Ont. Canada Imp. T-2 1960 1 Peto Seed Co., Saticoy, Calif. T 6003 1960 T6003 1 L. Butler, Univ. of Toronto, Canada Ark. 60-19-1 1961 60-19-1 J. McFerran, Ark. Agr. Exp. Sta., Fayetteville Rutgers 1961 Purdue Alumni Seed Imp. Assoc., Lafayette, Ind. Roma 1961 Joseph Harris Co., Inc., Rochester, N. Y. Gardener 1961 54- 179 (Lot 59-23) H. M. Munger, N.Y. Agr. Exp. Sta., Ithaca NY 59-400 1961 59-400 H. M. Munger, N. Y. Agr. Exp. Sta., Ithaca H 1369 1961 H 1369 H. J. Heinz Co., Bowling Green, Ohio ES 24 1961 Eastern States 24 H. J. Heinz Co., Bowling Green, Ohio Ace-VF 1961 Alpha Seeds, Lompoc, Calif. Brehm's Solid Red . 1961 91522, V 982-1 Eastern States Farmers' Ex- change, W. Springfield, Mass. MAT 1961 MAT-D6130 Ferry Morse Seed Co., Rochester, Mich. BULLETIN No. 685 [April, Table 2. Reasons for Inclusion of Varieties or Strains in Experiment Variety Fruit characteristics Control variety Color res^t- a nee Firm- pH and Total ness acidity solids Notes 1252 1483 Garden State . Y 13 Y 112 Y206 Kc 109 Kc 146 MRS 193 Imp. T-2 T6003 Ark. 60-19-1. Rutgers Roma Gardener NY 59-400 H 1369 ES 24 Ace-VF Brehm's Solid Red. MAT... High pigment(A/>) High acid line High pigment (hp) " Crimson" color CPC-2 type (California Packing Corp.) "Crimson" color? "Dark red" color from Lycopersicon pimpitullfolium Paste type fruit Soft fruit Dark green immature fruit color similar to high pig- ment, but not hp hp Table 3. Temperatures and Rainfall During the Growing Season of 1961 at the Vegetable Crops Research Farm, Urbana Date Temperature, F. Maximum Minimum Mean Precipitation for week (in.) May 21 through May 27 68 38 53 .5 May 28 through June 3 77 53 65 .1 June 4 through June 10 82 59 71 5.9 June 1 1 through June 17 75 56 66 T June 18 through June 24 77 52 64 2.1 June 25 through July 1 87 58 73 .0 July 2 through July 8 80 58 69 .8 July 9 through July 15 83 58 71 T July 16 through July 22 83 66 74 1.2 July 23 through July 29 84 65 75 2.2 July 30 through Aug. 5 85 69 77 2.0 Aug. 6 through Aug. 12 82 63 73 .0 Aug. 13 through Aug. 19 86 58 72 T Aug. 20 through Aug. 26 75 56 66 T Aug. 27 through Sept. 2 87 65 76 .0 Sept. 3 through Sept. 9 88 66 77 .0 Sept. 10 through Sept. 16 80 57 68 1.4 Season total .. .. 16.2 Season mean 81 59 70 Weekly mean . . . . .95 1962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS The plots were sampled by selecting uniformly shaded fruits at in- cipient color, or at the so-called "turning stage." The samples were placed in an air-conditioned ripening chamber, the temperature of which was maintained at 65 1.5 F. Samples were ripened for both 7 and 14 days before analysis. Measurements were made on each sample for color, firmness, pH, total titratable acidity, total solids, soluble solids, and weight of fruits. Measurements of resistance to cracking were also made, but on a separate sample. When the experiment was designed, it was thought that one replica- tion could be analyzed for the various quality factors during a single day. Therefore, two days would be necessary to complete a given sampling date. The field plots were sampled at two separate dates August 15 and 16, and August 29 and 30, 1961. Fruits of the first date were analyzed after only 7 days of ripening. The second sampling was ripened and analyzed after both 7 and 14 days. The samples were handled and analyzed in the following manner. A minimum of 10 fruits per sample was weighed and a median section, one-half inch thick was cut from each fruit. The slices to be tested were placed on a flat plexiglass plate of a model of the Illinois Firmness Tester originally described by Foda (3) and by Garrett et al. (4). A plastic container was placed on a plunger with a diameter of one-half inch, which was then placed in position on the tomato slice. The weight of the plunger and empty container was 314 grams. Care was taken to center the plunger on homogeneous inner wall tissue free from concentrations of vascular elements. The solenoid valve was opened by activating a mercury switch which allowed water to flow from a reservoir into the container. The mercury switch automatically shuts off the flow of water when the combined weight of the water, container, and plunger fully compresses (punctures) the flesh of the slice. The container was calibrated to read the weight of the water to 0.1 of a pound. Data were expressed in pounds of water necessary to compress the sample, and the larger the value the firmer the flesh of the fruit. These data can readily be converted to pounds per x + 69 square inch by applying the formula 1Q ' . . The variety Roma was not tested for firmness. Fruits of this variety are generally two-loculed and the inner wall tissue of the fruits are not thick enough to test with the one-half inch plunger. After testing for firmness the whole fruit samples were blended for 2 minutes in a one-gallon Waring Blendor. A sample of approximately 500 ml. of the blended juice was taken for further analyses after having been strained through a doubled layer of cheesecloth to remove skins and seeds. 8 BULLETIN No. 685 [April, Measurements of total carotenoids and carotene were made using the spectrophotometric method of McCollum (8). Percent transmittance of the total carotenoid and carotene samples were both read at 450 rmi on a Bausch and Lomb Spectronic 20 colorimeter. Total carotenoid extracts of the 14-day samples were cut 1 : 1 with pure hexane before they were read. Transmittance data were converted to milligrams per 100 grams fresh weight. The ratios of total carotenoids to carotene (T/C) were calculated as a numerical expression of visual color. Color readings were made with a Hunter Color and Color Difference Meter using the large aperature and large area illumination with the Campbell standard (Rd = 6.9, a = 34.9, b = 16.6) and recorded as a/b ratios. Hunter read- ings on the first sampling date were not obtained due to a malfunction of the instrument. The pH and total acidity were measured on a Beckman automatic titrator. Readings were made on 10-gram samples of tomato juice to which 90 ml. distilled water had been added. Titrations were made with 0.1N NaOH to an end point pH of 8.1. Total titratable acidity was expressed as grams of citric acid per 100 grams fresh weight. Total solids were determined by drying 20-gram samples of juice for 24 hours to a constant weight in a drying oven at 80 C. Soluble solids were measured with a Bausch and Lomb hand refractometer on samples prepared by straining a drop of juice through four layers of cheesecloth. Samples to be tested for resistance to cracking were selected on Sep- tember 18, 1961. Ten fruits at incipient color were harvested from each plot. All fruits were tested by the vacuum-immersion method of Hepler (6). Fruits were evacuated at seven inches of mercury and immersed in water maintained at 20 C. for 3 hours. The cracks on individual fruits were then classified as radial or concentric and measured in centimeters with a map measure. The total length of both types of cracks was also recorded. The raw data were transformed to the square root of x + Vz before being analyzed statistically. The data were analyzed statistically by means of the analysis of variance method. In all instances, except for fruit cracking, three sepa- rate analyses were calculated. They are as follows : ( 1 ) the comparison of the two 7-day samples; (2) the comparison of the 7- and 14-day samples harvested at the same date; and (3) the analysis of the 14-day samples. Since data for the first sampling date were not available for the Hunter a/b readings, the analysis of variance of the 7-day samples of the second date was calculated. The accidental loss of the 14-day sample of the variety Brehm's Solid Red necessitated the calculation of a missing subplot value. An orthogonal breakdown of the degrees of freedom for varieties was made for the three measurements of cracking and for firmness. The indi- 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 9 vidual comparisons were made on the basis of the classification of the varieties as listed in Table 2. At the time the experiment was designed, grouping varieties into specific color classes was not considered feasible since sufficient knowledge of the basis for some of the color differences was not available. Therefore, no breakdown was computed for the measurements of fruit color. Since only one or two varieties were pre- viously classified as sources of the other characters, no individual com- parisons were made. In all instances, the means of the 7 + 7- and the 14-day samples were ranked and the shortest significant ranges were calculated by means of Duncan's "Multiple Range Test" (2, 5). Additional studies of an exploratory nature were conducted on a por- tion of the varieties and strains with regard to the holding capacity of fruits on a plant, and the resistance of fruits to breakage when dropped. To determine the holding capacity, fruits at incipient coloring of eight varieties with varying levels of firmness and resistance to cracking were tagged on August 24, 1961. Tagged fruits were harvested two weeks later. Fruits were counted, weighed, and graded into marketable and cull classifications. Four types of defects on the culls were recorded. Those fruits decayed beyond recognition of the causal factor were classified as total decay. The other defects were sunburn, decay at cracks, and ground rot. To determine the nature of the variables involved in the resistance of fruits to breakage, a series of samples was tested. Factors studied were height of drop and the number of times dropped at a given height to induce cracking, stage of maturity, size of fruit, time of day, moisture content and temperature of fruits, and varietal differences. In most tests, the standard, crack-resistant variety Kc 146 was used. The variety Kc 109 was used in the study on the effect of fruit size since a wider range in size was available in this line. Ten varieties or strains from the replicated experiment were tested to determine the extent of variation among varieties. In addition, fruits of a line homozygous for the gene sticky peel (pe), which was reported by Hepler (6) to be highly resistant or immune to cracking, was tested. In all instances unless otherwise indicated, the fruits were dropped on the stylar end on a hard surface. The effect of dropping fruits of the variety Roma on both the stylar end and the side was tested. To study the effect of moisture content and temperature in fruits, samples were infiltrated with cool and warm water at 21 and 35 C. respectively. Infiltration was accomplished in the vacuum-immersion crack resistance tester at 5 inches of mercury. Evacuation was continued until air bubbles ceased coming from the samples. In some instances, data were taken on fruit weight, total carotenoid pigments, and firmness on samples com- parable to those tested for breakage. 10 BULLETIN No. 685 DISCUSSION OF RESULTS [April, Four measurements of fruit color total pigment, carotene, ratio of total pigment to carotene (TO, and Hunter a b ratios In all instances, highly significant differences were measured among the 21 varieties or strains tested for the four measurements of fruit color (Table 4). There was no significant difference between the means of the two 7-day samples, but highly significant differences were measured be- tween the 7- and 14-day samples. In general, total pigments, T/C and a/b ratios increased in magnitude, but carotene decreased with ripening from the 7th to the 14th day after incipient coloring (Tables 5, 6, 7, and 8) . In only one instance was there any indication of a differential re- Table 4. Analysis of Variance of 21 Varieties and Strains Tested for Meas- urements of Fruit Color at Different Sampling and Testing Dates Mean squares for Source of freedom p >^ tt Carotene Ratio of total pig- ment to carotene (T/C) Hunter 1 a/b Total 7 83 1 1 1 20 20 20 20 7 82 2 1 20 20 1 20 20 2 40 2 1 20 19* + 7-day samples 8.8855 12.6675 9.5209 3.9128** . 1.0837 .7942 .5808 + 14-day samples 15.1470** . 7.1194** . 1.1491 57.2220** . .4712 .8058 14-day samples 1.4747* 4.0209** . .2759 0309 0051 0053 0391** 0052 0074 0047 0324** 0335** 0034 0408** 0083* 0037 0062 0093** 0016 .13 239.71 39.09 84.24** 7.79 9.27 12.94 6.30 132.44** 14.96 1315.35** 17.83 9.42 .38 94.16** 13.75 .0013 .0577** .0098 .0039 .0959** .0090 3.6333** .0092 .0061 .0152 .0473** .0049 Replications Sampling dates Error a Varieties Error b Varieties x sampling dates Error c . . Total Replications Varieties Error a Testing dates Varieties x testing dates. . . . Error b Total Replications Varieties Error 1 No 7-day samples for first sampling date. 1 One degree ol freedom less because of missing subplot value. * Exceeds .05 level of significance. ** Exceeds .01 level of significance. 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 11 Table 5. Ranked Varietal Means of Total Carotenoid Pigments and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7 + 7-day samples 14-day samples Variety or Mean Shortest (mgm./ significant Variety or Mean Shortest (mgm./ significant strain lOOgm.) ranges 1 strain lOOgm.) ranges 1 11252... 7.73 a ^1252 11.12 a fY 13 7.28 ab Y 13 9.58 b fHRS 193 6.45 abc Ark. 60-19-1 9.22 be fArk. 60-19-1 6.01 abed HRS 193 8.42 bed 1483 5.71 bed 1483 8.20 cde NY 59-400 5.64 bed NY 59-400 7.86 def Garden State .... 5.57 bed Rutgers 7.76 defg fT 6003 5.45 cd Garden State. . . . 7.60 defgh Gardener 5.36 cde fT 6003 7.31 defghi Kc 109 5.28 cde Gardener 7.26 defghi Rutgers 5.06 cde Roma 7.00 efghi Y 206 4.96 cde MAT 6.80 %hij Y 112 4.92 cde Kc 146 6.65 fgtujk Brehm's Solid Red 4.79 cde Kcl09 6.61 fghijk Roma 4.76 cde Ace-VF 6.58 fghijk Ace-VF. . 4.72 cde Y 206 6.48 ghijk Kc 146 4.46 de H 1369 6.39 hijk MAT 4.36 de ES 24 6.10 ijk H 1369 4.35 de Brehm's Solid Red 5.66 jk ES24 4.24 de Imp. T-2 5.54 jk Imp. T-2 3.64 e Y 112 5.42 k Mean and stand- ard error 5.270 520 7.310 .371 1 Means with the same letter are not different from each other at the .05 level of significance. t Varieties or strains classified as having fruits with improved red color. sponse of varieties at different sampling or testing dates carotene at 7 and 14 days. Carotene content is known to be subject to considerable variation, so such an interaction was not unexpected. It would appear that a satisfactory evaluation of the potential of a variety for develop- ment of fruit color can be obtained at one sampling date after either 7 or 14 days of ripening. It is obvious that maximum color has not devel- oped at 7 days, but differences in magnitude normally expressed at 14 days are also sufficient for separation at the earlier stage of ripeness. Four of the five varieties classified as having superior red color ranked at the top in total carotenoid pigments. The two high-pigment lines 1252 and Y 13 were also higher than those of the other varieties. The line 1252 tended to be superior to Y 13 in color. Foliage cover on Y 13 is rather sparse, and fruits were exposed to higher light intensity before sampling. The effect of illumination of fruits prior to the turning stage 12 BULLETIN No. 685 (April, has been previously studied by McCollum (9). Higher light intensity during fruit maturation increases total carotenoid production, but the proportional increase in carotene is higher than that of lycopene. The higher carotene content had an adverse effect on the T/C ratio, espe- cially in the Y 13 line. The total quantity of pigment present apparently influences the Hunter a/b ratio since the line 1252 ranked at the top in the a/b readings even though the T/G ratio was lower. The present results substantiate the findings of Thompson (12) where purees made from high pigment tomatoes had higher Hunter a/b readings than those made from normal tomatoes, but the T/C ratios were lower. It may be concluded that Hunter readings alone are not sufficient for the deter- mination of basic color differences. The line T 6003 was represented as having the "crimson" color, but it is doubtful if it has this character as typified by HRS 193. The nature of inheritance of this character has not as yet been established. The charac- Table 6. Ranked Varietal Means of Carotene and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7+7-day samples 14-day samples Variety Mean Shortest Variety Mean Shortest or (mgm./ significant or (mgm./ significant strain lOOgm.) ranges 1 strain lOOgm.) ranges 1 fY 13 .625 a fY 13 .450 a f!252 .510 ab f!252 .355 ab ES 24 .470 be ES 24 .355 ab Garden State .... .408 bed H 1369 .355 ab H 1369 .395 bcde MAT .355 ab fT 6003 .352 cdef Kc 146 .350 be Gardener .352 cdef Imp. T-2 .330 bed 1483 .348 cdef 1483 .315 bed Kc 109 .332 defg Rutgers .305 bcde fArk. 60-19-1 .328 defg Garden State. . . . .300 bcde MAT .325 defg |T 6003 .290 bcde Kc 146 .322 defg Gardener .290 bcde Ace-VF .312 defgh tHRS 193 .265 bcdef Brehm's Solid Red .302 defgh fArk.60-19-1 .260 bcdef fHRS 193 .295 defgh Ace-VF .255 cdef Imp. T-2.. .288 defgh Y 206. . . . .255 cdef Y 206 .282 defgh Y 112 .235 def Rutgers .280 efgh Kc 109 .210 ef Y 112 .248 fgh Roma .190 f Roma .212 gh NY 59-400 .190 f NY 59-400 .195 h Brehm's Solid Red .185 f Mean and stand- ard error .342 0.0361 .290 + 0.0283 1 Means with the same letter are not different from each other at the .05 level of significance. t Varieties or strains classified as having fruits with improved red color. 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 13 Table 7. Ranked Varietal Means of the Ratio of Total Pigment to Carotene (T/C) and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7 + 7-day samples 14-day samples Variety or strain Mean Shortest significant ranges 1 Variety or strain Mean Shortest significant ranges 1 NY 59-400 28.92 a 24.62 ab 22.18 be 20.55 bed 19.42 cde 18.50 cdef 18.02 cdefg 16.78 defgh 16.12 defgh 16.12 defgh 15.92 defgh 15.42 efghi 15.35 efghi 15.10 efghi 14.15 fghi 13.92 fghi 13.45 ghij 12.75 hij 12.22 hij 11.12 ij 9.25 j 16. 66 1.396 NY 59-400 42.75 36.90 . 36.15 31.90 31.80 31.40 26.40 26.00 25.90 25.75 . 25.40 25.40 25.40 25.20 23.05 21.35 19.25 19.15 18.15 17.35 16.95 26.27:4 a ab ab be be be cd cde cde cde cde cde cde cde cde de de de de de e :2.622 Roma Roma fHRS 193 fArk. 60-19-1 Kc 109 Y 112 fArk. 60-19-1.... Rutgers fHRS 193 f!252 Y 206 Brehm's Solid Red . 1483... 1483 Kc 109 fT 6003 Brehm's Solid Red. . Ace-VF fT 6003 . . Garden State. . . Rutgers Ace-VF Gardener . . . Y 206 f!252 Gardener Kc 146 Y 112.. Garden State . . . MAT. . . fY 13 Kc 146 . . Imp. T-2 MAT fY 13 H 1369 ES 24 H 1369 ES 24 Imp. T-2 Mean and stand- ard error 1 Means with the same letter are not different from each other at the .05 level of significance. t Varieties or strains classified as having fruits with improved red color. teristic color of the crimson material appears to be based upon a mod- erately high level of total pigments and a relatively low level of carotene thus giving favorable T/C and a/b ratios. The lower level of carotene is especially noticeable in the locular region, which generally has a rela- tively high level. The line Ark. 60-19-1 appears to have similar color characteristics to that of HRS 193. Wann and McFerran (13) postulated the inheritance of color typified by Ark. 60-19-1 to be multigenic. Addi- tional research will be needed to determine what relationship, if any, exists between these two sources of fruit color. The performance of the varieties NY 59-400 and Roma with respect to color is of interest. Both are very low in carotene and consequently high in T/C and a/b ratios. NY 59-400 also ranks high in total pigments, and appears to have a pigment potential somewhat similar to HRS 193 14 BULLETIN No. 685 [April, and Ark. 60-19-1. The Illinois high-acid line 1483, derived from a cross between Garden State and a high-acid selection of PI 163246 (111. Ace. 326), also has a rather high potential for production of total pigments, and ranks above average for carotene, T/C and a/b ratios. Inspection of the means in Tables 5, 6, 7, and 8 clearly indicates a number of varieties that have relatively low potential for production of fruit color. Poor color in most of these lines results from a combination of low total carotenoids and high carotene. The variety MAT, which was included because it had dark green, immature fruit color similar to that found in the high-pigment lines, had a relatively low potential for color. Although high chlorophyll content appears as a pleiotropic effect of the high-pigment gene, there apparently is little association between chlorophyll and total carotenoid pigments in the variety MAT. At the 14-day sampling, the carotene content of the two high-pigment lines, however, was not significantly greater than that of MAT. Table 8. Ranked Varietal Means of Hunter a/b and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 and 14 Days at 65 F. 7-day samples 14-day samples Variety Shortest or Mean significant strain ranges 1 Variety or strain Shortest Mean significant ranges 1 f-1252 .850 .815 .745 .740 .665 .665 .655 .645 .625 .605 .550 .510 .485 .480 .475 .430 .425 .410 .360 .250 .240 .554 + a ab abc abc abed abed abed abcde abcde bcde cdef cdef defg defg defg defgh defgh efgh fgh g l; .0700 J1252 2.255 2.250 2.175 2.150 2.050 2.015 2.010 2.005 2.000 1.995 1.985 1.985 1.940 1.920 1.880 1.870 1.865 1.795 1.755 1.755 1.705 1.9700 a a ab abc bed bcde bcde bcde cde cde cde cde def defg defg efg efgh fgh g h g h .0495 NY 59-400 Roma fHRS 193 fHRS 193. Roma NY 59-400 . 1483 |Ark. 60-19-1 ... fY 13.. Y 206 . . Kc 109 Ace-VF Y 112 1483. . . fY 13 Gardener fArk. 60-19-1.. . . Ace-VF. . Kc 146. . . Kc 109 . fT 6003 Rutgers Gardener JT 6003 ES 24 Garden State. . . Y 112 Kc 146 Garden State. . . Brehm's Solid Red Y 206 Brehm's Solid Red Rutgers ES 24 MAT MAT H 1369 Imp. T-2 Imp. T-2 H 1369 Mean and stand- ard error 1 Means with the same letter are not different from each other at the .05 level of significance. t Varieties or strains classified as having fruits with improved red color. 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 15 Three measurements of cracking radial, concentric, and total by vacuum immersion Highly significant differences were measured among the 21 varieties tested by the vacuum-immersion method (Table 9). Varieties classified as resistant had highly significantly fewer cracks than those classified as susceptible. Highly significant differences were also measured within both resistant and susceptible groups, except for concentric cracking within the resistant lines where the difference was significant at the 0.05 level. The measurement of concentric cracking is subject to greater error Table 9. Analysis of Variance of 21 Varieties or Strains Tested for Resistance to Radial, Concentric, and Total Fruit Cracking Source of variation Degrees of freedom Mean squares for Radial cracking Concentric cracking Total cracking Total 419 .46 13.42** 113.45** 6.43** 9.16** .74 .63 4.36 14.95** 45.01** 12.29* 14.01** 3.37** 1.55 1.09 21.13** 173.23** 14.25** 12.47** 2.19* 1.12 Replications 1 Varieties ... 20 Resistant vs. susceptible . . 1 Among resistant . 7 Among susceptible 12 Error 20 Sampling error 378 * Exceeds .05 level of significance. ** Exceeds .01 level of significance. variation than that of radial cracking as indicated by the F test of the error by the sampling error variances. The variation in concentric crack- ing is also reflected in the error for total cracking. These data fully sub- stantiate the findings of Hepler (6) in this regard. In general those lines classified as resistant tended to exhibit the highest resistance with a few exceptions (Table 10), thus attesting to the progress made in the breeding for resistance to cracking. The strain Ark. 60-19-1, which was not classified as resistant, exhibited a very good level of resistance to radial, concentric, and total cracking. HRS 193 had a very high level of radial crack resistance, but was very susceptible to concentric cracking. Imp. T-2, which was not classified as resistant, performed in a manner similar to HRS 193. Garden State exhibited very high concentric crack resistance, but was very susceptible to radial crack- ing. Roma gave the best overall performance in the test. The fruit shape of this variety undoubtedly has an important influence on the measured resistance. Of the standard fruit types, NY 59-400 gave the highest over- 16 BULLETIN No. 685 [April, 111 C/D ,5p * 'M JS.D .>.> cS cS cS CS tS o O o"> eo O U U U U tO tO Oi t^ CM CM O U V U U -OT3-O U m o> O co r- t^ CT> to co co r^ o^ r^ r^ in ^ CM ^^ ^ co -^ to +1 8 CM CM CO CO 1 S3 m in m * rj. **J"** coeocococo COCOCMCMCM-I co ^ co 5 -"B - : : :^ :::::: >x Is . i . i I s ! }l|| CO . C/3 h :2 : g c c4 . .co . . .~ tO ^* ' ^ ^ O CS ^ ^^ ^ u""y?^ c/^ooa:^- 1 " 1 ^ 4 1 4 H 1 1 -t j= j; J3 "* o mmooOTj- CT) co cr> uo co aitoinin 1 ^ COOCCDOI 00 o +1 CO i O CM co a> U 2 S3 <* TT T}- co co CO CO CO CO CO (MCMCMCMCM CM CM CM CM CO CM S > o 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 17 all performance, and along with Kc 109 should serve as a valuable source of resistance to cracking in future breeding research. The use of the vacuum-immersion method should greatly increase the precision in testing for resistance to cracking. The method minimizes environmental variation and is well adapted for testing performance of individual plants in large populations of segregating material. In this experiment, 420 individual fruits were selectively harvested, marked, evacuated, soaked, and measured in less than an 8-hour day. Four persons were involved with the harvesting and only two with the rest of the operations. Hepler (6) estimates that it should be possible to screen over 1,000 fruits per day if a scoring system is employed rather than actually measuring the lengths of cracks. Measurement of firmness of flesh Highly significant differences in firmness of flesh were measured among the 20 varieties tested (Table 11). A large portion of the variance is attributable to the difference between the means of the two groups firm and soft or normal fleshed varieties. Highly significant variation was also measured among the varietal means within each of the two groups. No significant difference was measured between the means of the two 7-day samplings, but the decrease in firmness following ripening from 7 to 14 days was highly significant. No differential response of varieties at different testing or sampling dates was measured, thus indicating that an adequate evaluation of the firmness of varieties can be obtained at one sampling date after either 7 or 14 days of ripening. Since the magni- tude of the differences between firm and soft varieties is greater at seven days (Table 12), more precise separation would be expected at the earlier stage of ripeness. In general, the varieties classified as being firm tended to exhibit the highest degree of firmness (Table 12). The two high-pigment lines, Y 13 and 1252, tended to have the highest degree of firmness of the varieties tested. The superior performance of Y 13 in comparison with 1252 is of interest, because the characteristic firmness of the flesh of these and other high-pigment lines appears to be completely associated with the high-pigment gene, hp. It is not possible at the present time to deter- mine whether this difference is due to modifying genetic factors or to an interaction of environment with the residual genotype of the two lines. The Illinois high-acid line 1483 exhibited a surprisingly high degree of firmness, testing well within the range of the firm varieties. NY 59-400 and ES 24 also showed considerable merit, and should serve as valuable sources of firmness in future breeding research. The variety Gardener, which was included in this experiment since it was reported to have 18 BULLETIN No. 685 [April, * * * * c S * * CT3 _ * m o S 1 8r^ in m co to T* m co CM o CO JS S3 S , tO CM "a W O *"^ i bb'o'S a u o OD CD CO Q CO a i c : ,Jg d g 8 .2 n "iS 8 TJ 03 PI C/3 R! .2 OT ^ bo be UH ptj ^ (jj CO w bo CO to G cu # * * * * '2 ^ C u * * * * * co in r- o O to CD co & "^ (^ Ctf Tt*r^CDco~^^t o COO (MtOOCDOCD CO "t'CD H ^j CT *-^ CD CO r^. ^ O t^- O O SM ^* bo CO CM .S 01 U ' S "* "a 1 i tD CM s S S ~^ R) ho O ^^ > ^ >, P 1 CO -" CD CD CD CD C JS CM Cg uJ3 ^J .^H CC *y ^ fj o o R* bc-^ +j +* ?* 3 > 3, ^5 .H .h S S fe -^ .U -Q n O C*< o S*c3^ t| ' < ^ H> "rt S < * * * * i i i * * * * I c S S9 2 5 S. tOCDCO "^CMr^CDCD O CM m i rt- CO CO o r^ * co in in CM o ,2 gs _w * ST CD 2 CO CQ u H "a S S <> CM S u o S O Jj CD ~^ ^^ ~* CD CD CD CD 01 T3 i g^i j| :|gj S 1 3*0 iS O u C/3 RJ 2 be ^ i bow a It; III It I o tg H (^ c W > W > a a 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 19 Table 12. Ranked Varietal Means of Firmness of Flesh of Fruits and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7+7-day samples 14-day samples Variety or strain Mean (Ib.) Shortest significant ranges 1 Variety or strain Mean db.) Shortest significant ranges 1 fY 13 2.80 a 2.37 b 2.37 b 2.29 b 2.12 be 1.91 bed 1.84 cde 1 . 79 cdef 1 . 73 cdef 1 . 73 cdef 1.67 cdefg 1.56 defg 1.54 defg 1.50 defg 1.39 efg 1.38 efgh 1 . 37 efgh 1.32 fgh 1.22 gh .91 h 2.21 1.49 1.74 + 0.143 tY 13.. 2.63 a 2.17 ab 2.09 abc 2.01 abed 1.86 bcde 1.61 bcdef 1.54 bcdefg 1.52 cdefgh 1.46 cdefgh 1.43 defgh 1.39 defgh 1.36 efgh 1.23 efghi 1 . 18 fghi 1 . 18 fghi 1.14 fghi .96 ghi .92 ghi .91 hi .68 i 1.87 1.46 1.46 + 0.182 f!252 1483 fNY 59-400 fNY 59-400 fES 24 f!252. jBrehm's Solid Red 1483 fES 24 fH 1369 Garden State .... fH 1369 Ark. 60-19-1 Garden State .... fHRS 193 fHRS 193 Kc 146 fBrehm's Solid Red Ace-VF Rutgers Imp. T-2 Rutgers Kc 109 Kc 146 Y 206 Imp. T-2 Ace-VF Y 206 Gardener Kc 109 Y 112 Gardener Ark. 60-19-1 Y 112.. T 6003 T 6003. . MAT. MAT . Mean of firm varieties Mean of soft varieties General mean and standard error. 1 Means with the same letter are not different from each other at the .05 level of significance. t Varieties or strains classified as having firm fruits. fruits with soft flesh, did test in the lower range of firmness. However, the means of several lines were lower than Gardener, but not significantly so. The apparent increase in firmness of the strain Ark. 60-19-1 from 7 to 14 days can not be considered a true effect. The combined mean of the two 7-day samplings was low because the first sample was very low, with a value of 1.01. The mean of the second sample was 1.62, which is larger than the 14-day sample that was harvested at the same time. Although the method can not be considered objective, fruits of Ark. 60-19-1 do feel fairly firm to the touch. 20 BULLETIN No. 685 [April, Measurement of pH, total titratable acidity, soluble and total solids, and fruit weight In all instances, differences between the 21 varieties for the five meas- urements were highly significant (Table 13). No significant difference was measured between the means of the two 7-day samplings. Highly significant differences were measured between the means of the 7- and the 14-day samplings for the four measurements of quality, but not for fruit Table 13. Analysis of Variance of 21 Varieties or Strains Tested for pH, Total Titratable Acidity, Soluble Solids, Total Solids, and Weight of Fruits at Different Sampling and Testing Dates Source of variation Degrees of freedom Mean squares for Total pH titratable acidity Total solids Fruit weight 7 + 7-day samples Total 83 Replications 1 .0107 .00016 .240 .027 2931.13 Sampling dates.. . 1 .2465 .00053 .130 .000 211.85 Error a 1 .1036 .00010 .020 .146 390.01 Varieties 20 .0367** .02281** .849** .833** 7203.90** Error b 20 .0076 .00062 .025 .069 553.36 Varieties x sam- pling dates 20 .0056 .00145** .119* .077 732.49** Error c 20 .0046 .00041 .045 .054 223.67 7 + 14-day samples Total 82 1 Replications 1 .0629** .00264* .000 .298 5801.71** Varieties 20 .0344** .02131** .825** .849** 5595.36** Error a 20 .0055 .00055 .051 .132 460.56 Testingdates 1 .8804** .10240** 1.600** .670** 427.51 Varieties x test- ing dates 20 .0032 .00104 .044 .048 86.25 Error b 20 1 .0059 .00058 .037 .050 110.05 14-day samples Total 40 1 Replications 1 .0029 .00323* .130 .381 3077.15** Varieties 20 .0146** .00800** .320** .405** 2947.91** Error 19 1 .0019 .00041 .044 .105 209.92 1 One degree of freedom less because of missing subplot value. * Exceeds .05 level of significance. ** Exceeds .01 level of significance. 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 21 weight. The pH increased while total acidity, total solids, and soluble solids decreased with ripening (Tables 14, 15, 16, 17, 18). Varieties did not respond differentially when ripened from 7 to 14 days. However, statistically significant differential responses of varieties were measured in the comparison of the two 7-day samplings for total acidity, soluble solids, and fruit weight. These data clearly indicate the influence sea- sonal effects have on total acidity, and to a lesser degree, soluble solids. Additional research is needed on the improvement of sampling procedures for these two constituents. Table 14. Ranked Varietal Means of pH of Fruits and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7+7-day samples 14-day samples Variety or strain Mean Shortest significant ranges 1 Variety or strain Mean Shortest significant ranges 1 Garden State .... 1252 4.40 4.39 a ab Garden State. . . . 1252 4.50 4.50 a a Rutgers 4.34 abc Rutgers 4.45 ab Y 13 4.28 abed T6003 4.40 abc Y 112 4.28 abed Y 206 4.40 abc T 6003 4.25 bcde MAT 4.40 abc Y 206 4.24 cdef Ace-VF 4.40 abc Gardener 4.22 cdef Y 112 4.38 bed Imp. T-2 4.21 cdef Gardener 4.38 bed MAT 4.20 cdef Imp. T-2 4.38 bed Kc 109. . 4.19 def Kc 109 4.35 bed H 1369 4.19 def H 1369 4.35 bed Kc 146 4.18 def Kc 146 4.35 bed Roma 4.18 def Roma 4.35 bed Brehm's Solid Red 4.16 def Y 13 4.32 cd HRS 193 4.15 def Ark. 60-19-1 4.32 cd ES 24 4.15 def Brehm's Solid Red 4.30 cd NY 59-400 4 12 defe HRS 193 4.30 cd Ark. 60-19-1.. . 4 11 efe ES 24 4.28 d Ace-VF. 4 09 f fe NY 59-400 4.28 d t!483. . 4.00 s t!483. . 4.10 e Mean and stand- ard error. . 4.200.044 4.36 + 0.031 1 Means with the same letter are not different from each other at the .05 level of significance. t Classified as having fruits with low pH. 22 BULLETIN No. 685 [April, Table 15. Ranked Varietal Means of Total Titratable Acidity of Fruits and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7+7-day samples 14-day samples Variety or strain 1 Mean (gm./ i OOgm.) Shortest significant ranges 1 Variety or strain 1 Mean (gm./ J OOgm.) Shortest significant ranges 1 f!483 . . . .690 a t!483. . . .610 a Ark. 60-19-1.. . .668 a Ark. 60-19-1 .555 b NY 59-400 .536 b NY 59-400 .457 c Ace-VF. .512 be HRS 193 .434 cd HRS 193 .508 be ES 24. . .426 cde Brehm's Solid Red MAT .508 .481 be cd Brehm's Solid Red Y 13 .414 .413 cdef cdef ES 24 All cd MAT .410 cdef Gardener .462 de Gardener .407 defg Kc 109 .462 de Y 112 .404 defg Y 13 .453 def Kc 109 .398 defgh Y 112 .453 def Ace-VF .395 defgh Y 206 .450 defg Y 206 .383 efgh 1252 .450 defg H 1369 .380 efgh T 6003 .448 defg 1252 .377 efgh Kc 146 .434 efgh Kc 146 .371 fgh Rutgers. .434 efgh Rutgers .368 fgh Garden State .... H 1369 .420 412 fgh feh Garden State. . . . T 6003 . .368 .365 fgh feh Roma 409 gh Imp. T-2 359 eh Imp. T-2 .400 g h Roma .353 h Mean and stand- ard error. . .479 + .0124 .412+0 .0143 1 Means with the same letter are not different from each other at the .05 level of significance. t Classified as having fruits with high total titratable acidity. Table 16. Ranked Varietal Means of Soluble Solids of Fruits and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7 + 7-day samples 14-day samples Variety or strain Mean (%) Shortest significant ranges 1 Variety or strain Mean (%) Shortest significant ranges 1 Ark. 60-19-1. . . 6.80 a Ark. 60-19-1 . 6 65 a HRS 193 6.23 b Brehm's Solid Red 6 10 b Brehm's Solid Red . 6.15 b HRS 193 6.03 be MAT 5.87 c NY 59-400 5 90 bed 1252 5.87 c MAT 5 83 bcde 1483 5.85 c Gardener 5 83 bcde Garden State 5.85 c 1483 5.75 bcdef Gardener 5.75 cd Garden State 5 67 cdef NY 59-400 5.73 cd 1252 5 57 defg Y 112 5.70 cde Rutgers 5 57 defe (Table is concluded on next page) 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS Table 16. Concluded 23 7+7-day samples 14-day samples Variety or strain Mean . Sh rtest ,m\ significant ranges 1 Variety or strain x/r Shortest M ^, n significant ranges 1 T 6003 5.63 5.57 5.55 5.50 5.43 5.27 5.25 5.17 5.15 4.93 4.77 5.62 + cde de de de ef fg % g h e h . hi i ,079 Y 112. 5 53 defg efgh efgh fghi ghi hi M 9 9 y j 113 Rutgers T6003 5 47 Kc 109 Kc 109 . 5 47 Ace-VF Ace-VF 5 37 Kc 146 Kc 146 5.23 Y 206 ES 24. 5 13 Y 13 Roma 5 05 ES 24 Y 206 5.03 Roma Y 13 5.03 H 1369 H 1369 5.00 Imp. T-2 Imp. T-2 4.75 Mean and stand- ard error 5.380. 1 Means with the same letter are not different from each other at the .05 level of significance. Table 17. Ranked Varietal Means of Total Solids of Fruits and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7+7-day samples 14-day samples Variety or Mean Shortest significant Variety or Mean Shortest significant strain ranges 1 strain ranges 1 Ark. 60-19-1 6.31 a Ark. 60-19-1 . . 6.00 a HRS 193 5.69 b HRS 193 5.62 ab Brehm's Solid Red 5.69 b Brehm's Solid Red 5.62 ab MAT 5.44 be MAT 5.25 be Garden State. . . . 5.44 be NY 59-400 5.25 be NY 59-400 5.38 be Gardener 5.25 be Gardener 5.25 cd T 6003 5.12 bed 1483 5.25 cd Garden State .... 5.00 bcde fY 112 5.19 cde tY 112 5.00 bcde Rutgers 5.06 cdef Rutgers 5.00 bcde 1252... 5.06 cdef 1252 4.88 bcde Ace-VF 5.06 cdef Kc 109 4.88 bcde T 6003 5.00 cdef 1483 4.75 cde Kc 146 5.00 cdef Ace-VF 4.62 cde Kc 109 4.88 def Kc 146 4.62 cde Roma 4.88 def Roma 4.62 cde ES24 4.75 ef ES 24 4.62 cde Y 13 4.75 ef H 1369 4.62 cde H 1369 4.62 f fY 206 4.38 de fY 206 4.62 f Imp. T-2 4.38 de Imp. T-2 4.19 g Y 13 4.25 e Mean and stand- ard error 5.120.131 4.940.229 1 Means with the same letter are not different from each other at the .05 level of significance, t Varieties or strains classified as having fruits with high total solids. 24 BULLETIN No. 685 [April, Table 18. Ranked Varietal Means of Fruit Weight and Shortest Significant Ranges for Two Samplings Harvested at Incipient Coloring and Ripened for 7 Days, and for One Sampling Harvested and Ripened for 14 Days at 65 F. 7 + 7-day samples 14-day samples Variety or strain Mean (gm-) Shortest significant ranges 1 Variety or strain Mean (gm.) Shortest significant ranges 1 Kc 146 210.5 a Imp. T-2 . . 207.9 a Y 112 208.1 a Y 112 205.1 a Garden State .... 197.4 ab Brehm's Solid Red 183.6 ab Imp. T-2 196.0 ab Kc 146 175.5 abc Y 206 170.3 be ES 24 169.3 bed ES 24 168.6 be Ace-VF. . 165.3 bcde Ace-VF 167.1 be Y 206 163.7 bcde Kc 109 161.2 be Garden State 160.1 bcde 1252 155.3 cd MAT 141.9 cdef Brehm's Solid Red 151.6 cd 1252 141.7 cdef MAT 142.9 cde Kc 109 140.3 defg Rutgers 138.4 cde Rutgers 139.3 defg NY 59-400 131.6 cdef H 1369 133.6 efgh Gardener 119.6 defg NY 59-400 115.2 fghi Y 13 116.2 defgh Gardener 112.8 fghi H 1369. . 111.3 efgh HRS 193.. 110.5 fghi HRS 193 106.7 efgh 1483 107.0 ghij 1483 98.9 fghi Ark. 60-19-1 99.9 hij Ark. 60-19-1 86.4 ghi Y 13 97.9 J T 6003 79.5 hi T 6003 77.1 J Roma 65.5 i Roma 74.1 J Mean and stand- ard error 142.1 11. 76 139.1 + 10.24 1 Means with the same letter are not different from each other at the .05 level of significance. pH and total titratable acidity. As expected, the Illinois high-acid line 1483 had significantly lower pH and higher acidity than any other line tested, with the exception of Ark. 60-19-1, at the 7-day sampling dates for total acidity (Tables 14 and 15). Ark. 60-19-1 exhibited a surprisingly high level of acidity, not having been selected for this character. Several other strains including NY 59-400, HRS 193, Brehm's Solid Red, and ES 24 merit consideration as sources of variability for lower pH and higher acidity in future breeding research. The variety Ace-VF appeared to have a good level of acidity and low pH in the 7-day samples, but the levels did not hold up during ripening to 14 days. It is of interest to note that most of the strains having the highest degree of flesh firmness, with the exception of the two high-pigment lines, also have the highest levels of acidity and the lowest pH. Research is needed to determine if any causal relationship exists between acidity and firmness in tomato fruits. 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 25 Soluble and total solids. The relative rankings of the varieties were approximately the same for both soluble and total solids. The strain Ark. 60-19-1 was outstandingly high in both measurements. Brehm's Solid Red and HRS 193 also tested high. The two lines Y 112 and Y 206 respec- tively had only average and below average levels of total solids. The soluble solids readings on these two lines were similar to that of total solids. It may be concluded that Y 112 and Y 206 do not have genetic factors for high solids content. Several varieties were consistently low in solids. It would appear that progress could be made in breeding for higher levels of solids than now exist in the standard varieties. Fruit weight. The data in Table 18 give some indication of the varia- tion in fruit weight among the varieties and strains tested. More useful estimates of fruit weight undoubtedly could be obtained by other methods since the samples taken were selected for uniformity, which probably introduced biases of an unpredictable nature. Holding capacity of fruits on the vine Significant varietal differences in the holding capacity of fruits on the vine are indicated in the preliminary results (Table 19). It is obvious that holding capacity or what might be termed "field or vine storage" of fruits depends in part on the extent of firmness and the relative resistance to cracking of the fruit. Garden State typifies what can be expected of a variety lacking both firmness and resistance to total cracking. It is not possible to tell from these data whether firmness or crack resistance is the more important factor. It is obvious that if fruits do not crack the prob- ability of loss through decay is decreased. HRS 193 ranked at the top even though it has only average firmness and potentially high susceptibility to total cracking. Actually this strain has a high level of resistance to radial cracking, and the fruits were relatively free of cracks in the field. Severe cracking in the field was only noted on Garden State and 1252. The relative importance of firmness is illustrated by the below average performance of Kc 109 and Kc 146, both having a high level of crack resistance, but only average level of firmness. It appears that the firmness of 1252 tended to partially offset the high susceptibility to cracking in this line. The classification of defects on culls gives an indication of the nature of the loss. Loss of fruits by sunburning indicates relatively poor foliage cover, as was observed on the varieties Roma, Brehm's Solid Red, Kc 109, Kc 146, and ES 24. Of the varieties with inadequate foliage, only Brehm's Solid Red did not have a rather high amount of sunburned fruits in the tagged samples. Loss by sunburning would appear to have little relation- ship to the other forms of loss. On the other hand, excessively heavy foliage would tend to favor an increase in ground rot. 26 BULLETIN No. 685 [April, S u *. 8 "u

CM r* r^ CM co CO * * r^ in co 1 M -H CM CM CM . , _ M S" 03 Q cd 3 * _ u bc^ -Q .__ ,>. o b bo u ^a J _c ^ "S. u 3 MlC' CT) eo to CM m i~ to CM * c S ^ <*> co co * ' CO CM * 1 e ~a O t O O Ot^ O co ^, O "o U 1 u O ' C V 1 "5 c 3 3 i tO O O 05^0^ H 'S. C/3.Q 60 i r- S u O '-* C C g| M CMO O O CO I*- * O 03 O 18 CT> o m o CO CO t^ CO o to co to r^ to to co "3-1 o u o be ) ^ +2 a bo O-jJ rt 3 r^ OtOCO co CM a> co H S **" O O O CO t~- a> CT) o to 13*^ t ^< o co r~- 1^ to .^ ^' " 03 ' *" ""^ S 1-J-* o 3* S O" o oo to in vo r2 j'3;3 ^H in o t^ o to toco E"y H ^ si 1 V 3 s co m co co CO O5 tO O5 ^J< d'3 Tf * CM -< to co <* c bo h ^ ,5)S S ""ta 3 ; ! -a '. a 13 4) o X : \& "" O -o c i M '. '.-Q o rt u 1 ci U 1 si :1 i/D |J u ^T^'S i "* O 3 Q j.. t> m o o u t3 V s s 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 27 Considerable additional research is needed to determine the environ- mental and plant factors involved in the holding capacity of fruits in the field. The importance of this characteristic in a variety adapted to efficient mechanical harvesting can not be overemphasized. Although other factors may be equally important, significant increases in holding capacity should be realized by increasing the level of firmness and re- sistance to cracking. Even with existing knowledge and breeding mate- rial, it would appear that progress can be made in breeding for varieties that will hold fruits in a marketable condition for longer periods of time than is now possible with existing commercial varieties. Factors affecting breakage induced by dropping fruit To study the effect of height of drop, field-ripe fruits of the variety Kc 146 were dropped from heights of 1, l!/2, and 2 feet (Tables 20 and 21). Thirty fruits were used in each sample and a firmness test was run on 15 fruits of a comparable sample. The increase in breakage was es- sentially linear with increased height. The fruits that did not break at the first drop were then dropped from the same height repeatedly until break- age was induced. The number of times dropped was recorded and presented as a frequency distribution in Table 2 1 . From the standpoint of mechanical harvesting, these data indicate that drops within the machine of more than one foot, or more than two or three drops at one foot would appear to be excessive to fully ripe fruit. As expected, stage of maturity greatly influences the extent of break- age induced by dropping. It is important to note that maximum quality, as indicated by the extent of color development, is not reached until the fruits are fully mature. Since severe injury occurs when fully ripe fruits are dropped, consideration must be given to the engineering design of the mechanical harvesters, and the improvement of varieties able to withstand the handling. Smaller fruits appear to be less susceptible to breakage than larger fruits. This would indicate that varieties with smaller fruits would be best adapted to mechanical harvesting. Green and otherwise immature fruits create a sorting problem when fruits are harvested mechanically. For this reason it is commonly believed that the fruit size of a variety adapted to mechanical harvesting should be relatively large. If the sort- ing problem could be minimized by some means of concentration of fruit set and maturity, varieties with smaller fruits should perform more satis- factorily than those with larger. Time of day apparently has an influence on the extent of induced fruit breakage. Nearly twice as many fruits were damaged in the morn- ing. The difference may be explained in part by the relative content of 28 BULLETIN No. 685 [April, Mean Total Firmness Breakage after dropping Type of sample weight pigments Number Mean and Height Number Fruits tested and variety of fruits o f f ru its standard error of drop of fruits cracked (lb " } lOOgm.) tested (Ib.) (ft.) tested (%) OOO OOOO O) <> O O CO in CO CO OcoCMCOr -OO5cocoi^eot^r^co !1 e c o c o-c i-l O.C o c QC ^ ^J r^* ~- CM to O Tt to r^ r^ ^ ^ ^ TT CM o^^^co^^inintotor^c^oO} ooo omoo inmm o r~ co co r- int^toco^O i ncocoCT>intO't'in co co co CM CM co co * co CM coco co m to co co CM CM CM -^ in * m co eo eo -^ * - CM CM CM CM CM CM CM CM CM CM ' CM CM CM CM CM CM CM CM CM CM CM CM CM CM co in co ""* co in in CM * r^ co o CM o mo _ ^ -^ < CM CM i O OOOO O OO +i : : +1+1 +1+1 +1 : : +1+1 CM CO<>OCO CM * CT) r}< CO CM i < CM >n oooo co CMCM ~^ CO O O^ C?i O o co in in o CO \f) <> O O) CO m to o o o in * <* CM CO CO CO * CO <* tO COCO : : : : : : : : : : : :$ ^ :::::::::::::: ^H ^ J . ,S} CM U .... ' w " ^* % ~ 2 :::-:::: : : : : : 2 ^ a : : : : 2I'' >o>>ii x-x t '-j3 >t- Ssa .... (J...WM S^ Tf W Sjul .... e- 1 : : "8 : s2 ^. : " II : : S 1 -,' o B _w LJ 6 > *~ x ' T3 u o ' n C"e^ w *- ^u fi C'S"S"S ic S 1 -'-- >* ** S '5, .5*'3 a aco Rl "3ic |l52||tti^ll|l|||l||lfc||] ffi w w H S > . . "u O"> . . . ** . t> ^H -CO C/J 'c' O ] ^ ! C7> C to 6C *^1 . CO ^^ CM *"^ "^ ^* O K^ ^^ pj i-J 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 29 Table 21. Frequency Distribution of Number of 1-, VA-, and 2-foot Drops Necessary to Induce Breakage in Field-Ripe Kc 146 Tomato Fruits Height of drop 1 foot W2 feet 2 feet Number of times dropped to induce breakage Num- ber of fruits cracked Accu- mulated per- centage of fruits cracked Num- ber of fruits cracked Accu- mulated per- centage of fruits cracked Num- ber of fruits cracked Accu- mulated per- centage of fruits cracked I.. 3 10 20 40 67 70 80 93 100 12 10 3 4 1 40 73 83 97 100 21 8 1 70 97 97 97 97 100 2 3 3 6 4 8 5 1 6 3 7-11 4 12-16... 2 Number of fruits tested. . . 30 30 30 Mean and standard error of number of drops to in- duce breakage 5.1+0.68 2.1+0.21 1.4 + 0.14 water in the fruits at the two periods of time. The fruits in the morning would be expected to be more turgid, and therefore more susceptible to breakage by dropping. The results of the experiment in which the moisture content of fruits was increased by infiltration with cool and warm water are inconclusive. Infiltration with cool water had no ap- parent effect, but a slight reduction in breakage was observed in those fruits treated with warm water. If the effect of temperature is a true one, part of the reduction in breakage in the afternoon sample may be due to higher temperatures of the fruits. It is conceivable that elasticity of cells and epidermis may be increased at higher temperatures, thus affording a certain amount of protection to the fruits. Additional research is needed on these factors since the height of the drops for the infiltration study was only VA feet. More conclusive results undoubtedly would have been obtained if the drops had been at a greater height. Obvious differences in extent of breakage were measured in the com- parison of the 1 1 varieties. NY 59-400 performed outstandingly well in comparison with all the other lines. Undoubtedly the high levels of crack resistance and firmness in this strain are major factors in its resistance to breakage. The performance of NY 59-400 is striking when compared directly to Gardener, which has only average resistance to cracking, relatively soft flesh, and essentially the same fruit size. 30 BULLETIN No. 685 [April, Apparently resistance to cracking is not sufficient in itself to confer resistance to breakage since Kc 109 and Kc 146 performed similarly to Garden State. The higher level of crack resistance in Kc 109 may account for its slightly better performance compared to that of Kc 146. The lines Ark. 60-19-1, HRS 193, and ES 24, which have some degree of firmness and resistance to cracking, and Y 13, which has a good level of firmness but high susceptibility to cracking, gave intermediate performances in the test. Part of the difference may be attributed to size since Ark. 60-19-1, HRS 193, and Y 13 tend to have smaller fruits than the average variety. ES 24, similar to Kc 146, however, has larger than average fruit. The sticky peel line which has extremely soft flesh also gave an inter- mediate performance. Further research with this material is needed to determine if the sticky peel character has any commercial value. Roma, having a small fruit averaging approximately 0.15 pound, gave a slightly better performance than the intermediate varieties. Size and shape and internal structure of the fruits undoubtedly are important fac- tors in the apparent resistance of this variety. Considerably more break- age was obtained when fruits were dropped on the stylar end than on the side. Only the very ripest fruits cracked when dropped on the side at the 2-foot drop. External cracking of the fruits, of course, is not the only possible source of damage to a fruit after having been dropped. Bruising and subsequent enzymatic breakdown and development of off flavors in the fruits may be a serious problem and require further investigation. It may be concluded that progress should be possible in breeding varieties that will withstand handling injury. The strain NY 59-400 should serve as a valuable source of resistance in future breeding research. Summary of varieties or strains recommended for additional research The varieties or strains that gave superior performance for the va- rious fruit characteristics evaluated in the experiment are summarized in Table 22. No single variety ranked at the top for all categories, but NY 59-400 was included in nine out of the total fourteen. Roma, Ark. 60-19-1, and HRS 193 also ranked high on the list. It would appear that considerable improvement could be made by incorporating the desirable characteristics of these lines into commercially adapted varieties. How- ever, the efficient incorporation of these sources of variation depends to a large degree on the utilization of adequate sampling and testing pro- cedures. Considerable additional research is needed to improve sampling and testing techniques adapted to segregating populations. 7962] CHARACTERIZATION OF TOMATO VARIETIES AND STRAINS 31 Table 22. Summary of Varieties or Strains That May Serve as Future Sources of Variability in Plant Breeding Programs for the Improvement of Tomato Fruit Quality Fruit characteristics Varieties or strains Color High total pigments , 1252 Y 13 Ark. 60-19-1 HRS 193 High carotene . Y 13 1252 ES24 Low carotene . NY 59-400 Roma High T/C ratio . NY 59-400 Roma Ark. 60-19-1 HRS 193 High Hunter a/b ratio . 1252 Roma HRS 193 NY 59-400 Crack resistance Radial Roma HRS 193 NY 59-400 Imp. T-2 Kcl09 Concentric . Ark. 60-19-1 NY 59-400 Garden State Roma Kcl09 Total Roma NY 59-400 Ark. 60-19-1 Kc 109 Firmness . Y 13 1252 NY 59-400 ES24 1483 Resistance to breakage when dropped . NY 59-400 Roma pH . 1483 Total titratable acidity . 1483 Ark. 60-19-1 NY 59-400 Soluble solids . Ark. 60-19-1 HRS 193 Brehm's Solid Red Total solids . Ark. 60-19-1 HRS 193 Brehm's Solid Red SUMMARY Twenty-one varieties or strains of tomatoes were evaluated and char- acterized for color, crack resistance, firmness of flesh, pH, total titratable acidity, soluble solids, total solids, and fruit weight in a replicated experi- ment. All samples were selected at incipient coloring, and except for samples tested for resistance to cracking, were ripened at 65 1.5 F. for 7 and 14 days before analysis. In addition, tests of an exploratory nature were conducted on a portion of the varieties to determine the holding capacity of fruits in the field, and resistance to breakage of fruits when dropped. Highly significant varietal differences were measured in all of the constituents of quality evaluated. No differences were measured between the two 7-day samplings, but highly significant differences were found between the 7- and 14-day testing dates for all measurements except fruit weight. In most instances varieties did not respond differentially at the different sampling and testing dates. Therefore, one sampling date may be sufficient for an adequate determination of relative performance for most of the characteristics if adequate sampling techniques are employed. The strain NY 59-400 gave the best overall performance, ranking high in color, crack resistance, firmness, resistance to breakage when dropped, and total titratable acidity. The Illinois high-pigment line 1252 ranked high in total carotenoid pigments, carotene, Hunter a/b ratio, and firm- ness. The other high-pigment line Y 13 also ranked high in total pig- ments, carotene, and firmness. Roma ranked high in color, crack resist- ance, and resistance to breakage when dropped. The line Ark. 60-19-1 32 BULLETIN No. 685 had good color, crack resistance, high total titratable acidity, and high soluble and total solids. The Illinois high-acid line 1483 had the lowest pH and highest total titratable acidity, and a good level of flesh firmness. Kc 109 also ranked near the top in resistance to cracking. These varieties and strains should serve as good sources of variation for future tomato breeding research. Although considerable additional research is needed on the improvement of sampling and testing procedures, those used in this study would be feasible for use in a practical breeding program. LITERATURE CITED 1. Anderson, R. E. Factors affecting the acidic constituents of the tomato. Ph.D. thesis, Univ. of 111. 63 p. 1957. 2. Duncan, D. B. Multiple range and multiple F tests. Biometrics 11:1-42. 1955. 3. Foda, Y. H. Pectic changes during ripening as related to flesh firmness in the tomato. Ph.D. thesis, Univ. of 111. 66 p. 1957. 4. Garrett, A. W., Desrosier, N. W., Kuhn, G. D., and Fields, M. L. Evaluation of instruments to measure firmness of tomatoes. Food Tech. 14:562-564. 1960. . 5. Harter, H. L. Critical values for Duncan's new multiple range test. Bio- metrics 16:671-685. 1960. 6. Hepler, R. W. The measurement and inheritance of resistance to fruit cracking in the tomato. Ph.D. thesis, Univ. of 111. 83 p. 1961. 7. McCollum, J. P. Effect of sunlight exposure on the quality constituents of tomato fruits. Proc. Amer. Soc. Hort. Sci. 48:413-416. 1946. 8. - A rapid method for determining total carotenoids and caro- tene in tomatoes. Proc. Amer. Soc. Hort. Sci. 61:431-433. 1953. 9. - - Effects of light on the formation of carotenoids in tomato fruits. Food Res. 19:182-189. 1954. 10. Distribution of carotenoids in the tomato. Food Res. 20: 55-59. 1955. 11.- Sampling tomato fruits for composition studies. Proc. Amer. Soc. Hort. Sci. 68:587-595. 1956. 12. Thompson, A. E. A comparison of fruit quality constituents of normal and high pigment tomatoes. Proc. Amer. Soc. Hort. Sci. 78:464-473. 1961. 13. Wann, E. V., and McFerran, J. Studies of the inheritance of red color in fruits of Lycopersicon pimpinellifolium Mill. Proc. Amer. Soc. Hort. Sci. 76:524-529. 1960. 4M 4-62 76287 ffi&BANA 6851982