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 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN 
 
 OCT J 
 
 41994 
 
 L161 O-1096 
 
Yields of 
 
 CORN HYBRIDS 
 
 SILAGE 
 
 Second 
 Report 
 
 By W. B. Nevens 
 and G. H. Dungan 
 
 Bulletin 533 UNIVERSITY OF ILLINOIS 
 AGRICULTURAL EXPERIMENT STATION 
 
CONTENTS 
 
 PAGE 
 
 PLAN OF INVESTIGATION 367 
 
 "Block" Plan of Planting Used 368 
 
 Measuring Forage Yields 369 
 
 Other Measurements 370 
 
 RESULTS 371 
 
 Yields of Forage and Ears 371 
 
 Resistance of Plants to Lodging 377 
 
 Proportion of Ears in Forage 378 
 
 Ability to Mature Grain 378 
 
 Hybrids Were Similar in Protein Content 379 
 
 DRY MATTER IN FORAGE BEST INDEX 
 
 TO HARVEST STAGE 381 
 
 RATINGS OF TWENTY-SIX HYBRIDS 382 
 
 SUMMARY AND CONCLUSIONS . .383 
 
 Urbana, Illinois April, 1949 
 
 Publications in the Bulletin series report the results of investigations made 
 or sponsored by the Experiment Station 
 
YIELDS OF CORN HYBRIDS 
 HARVESTED FOR SILAGE 
 
 Second Report 
 
 By W. B. NEVENS and G. H. DUNCAN' 
 
 NEARLY ALL the Illinois corn acreage in recent years has been 
 planted to hybrids. While most of the crop is harvested for 
 grain, a substantial acreage is cut for silage. In 1945, 202,000 
 acres were harvested for silage, this acreage producing 1,737,000 tons 
 of forage. 2 Only six states cut a greater acreage than Illinois. Four of 
 those states had more milk cows than Illinois and the other two had 
 almost as many. 
 
 The production of each new hybrid raises questions about its merits 
 for silage as well as for grain. The value of a hybrid for silage depends 
 not only on its yield of forage but also on the proportion of the forage 
 the ears form, the ability of the plants to stand erect, and the general 
 adaptability of the hybrid to the region or locality. 
 
 A study of the value of corn hybrids for silage was begun at this 
 Station in 1935; a summary of the work for seven seasons was pub- 
 lished in 1942 as Bulletin 494, "Yields of Corn Hybrids Harvested for 
 Silage." The development of numerous new hybrids and the demand 
 for further information prompted a continuation of the investigation. 
 This bulletin summarizes the experimental findings for the five seasons 
 1942 thru 1946. 
 
 PLAN OF INVESTIGATION 
 
 The corn tested in the experiments here reported was grown the 
 first season (1942) on a farm near Urbana rented and operated by the 
 Department of Dairy Husbandry and during the next four seasons 
 
 1 By W. B. NEVENS, Professor of Dairy Cattle Feeding Research, and G. H. DUNCAN, Pro- 
 fessor of Crop Production Research. The authors gratefully acknowledge the advice of C. M. 
 WOODWORTH, Professor of Plant Genetics Research, concerning certain details of this study, the 
 services of R. S. SMITH, Professor of Soil Physics Research, and H. L. WASCHER, Assistant 
 Professor of Soil Survey Research, in classifying the soils of the fields on which the corn was 
 grown, and the help rendered by K. E. HARSHBARGER, Assistant Professor of Dairy Production 
 Research, in the collection of data. 
 
 2 Crops and Markets, U.S.D.A., January and May, 1946. 
 
 367 
 
368 
 
 BULLETIN No. 533 
 
 [April, 
 
 Table 1. Pedigrees of Illinois and U. S. Hybrids Tested for Yields of 
 
 Forage for Silage 
 
 Hybrid 
 
 Pedigree 
 
 Hybrid 
 
 Pedigree 
 
 111. 21 (WF9 X 38-11) (187-2 X Hy) 
 
 111. 126 (WF9 X 38-11) (Tr X L317) 
 
 111. 200 (WF9 X 38-11) (K4 X L317) 
 
 111. 201 (WF9 X 38-11) (187-2 X L317) 
 
 111. 206 (WF9 X 38-11) (5120 X L317) 
 
 111. 246 (WF9 X Hy) (187-2 X L317) 
 
 111. 246A-1 (WF9 X 187-2) (Hy X R57) 
 
 111. 247 (187-2 X 38-11) (Hy X L317) 
 
 111. 247-1 (187-2 X 38-11) (Hy X R57) 
 
 111. 273 (WF9 X 38-11) (l7-2 X 701) 
 
 111. 448 (38-11 X Kys) (K4 X L317) 
 
 111. 713 (WF9 X 38-11) (G X L317) 
 
 111. 784 (Hy X 5120) (K4 X L317) 
 
 111. 801 (5120 X Kys) (K4 X L317) 
 
 111. 804 (5120 X 38-11) (K4 X L317) 
 
 111. 838 (38-11 X Pr) (K4 X L317) 
 
 111. 855 (R4 X Hy) (G X L317) 
 
 111. 863 (R4 X Hy) (K4 X L317) 
 
 111. 877 (R4 X Pr) (K4 X L317) 
 
 111. 972 (WF9 X Hy) (701 X L317) 
 
 111. 972A-1 (WF9 X O7) (Hy X L317) 
 
 111. 972-2 (WF9 X Hy) (O7 X R57) 
 
 111. 2059(W) . . . (Ky27 X CI.61) (33-16 X K6) 
 111. 2077 (W). . . (33-16 X CI.61) (Ky27 X CI.43) 
 111. 2119(W). . .(Ky27 X CI.61) (33-16 X K64) 
 U.S. 13 (Hy X L317) (WF9 X 38-11) 
 
 (1943-1946) on Station land at Urbana. 1 Hybrids which have excellent 
 grain production records were chosen for these tests. 
 
 It was shown in the first of these studies (1935-1941, reported in 
 Bulletin 494) that hybrid corn was superior to open-pollinated in pro- 
 duction of forage. Therefore the use of an open-pollinated variety as a 
 standard, or check, was discontinued and a well-known and widely 
 grown hybrid, U. S. 13, was used in its place. Studies were made of 25 
 Illinois hybrids. The pedigrees of these hybrids are given in Table 1. 
 
 "Block" Plan of Planting Used 
 
 The land on which the corn was grown was prepared for planting 
 by either fall or spring plowing, followed by disking, harrowing, and 
 if necessary rolling to give a good seedbed. The seed was drilled in 
 rows 3.5 feet apart. The corn was cultivated first with a rotary hoe 
 and later with a shovel cultivator. 
 
 A ''block" plan of planting was followed in order to make it easier 
 
 1 The field used in the 1942 tests contains a combination of Flanagan and 
 Thorp Silt Loams and Drummer Clay Loam. The field is level. Drainage on the 
 Thorp Silt Loam is slow because of the character of the subsoil. 
 
 One of the two fields used in 1943, 1944, arid 1945 is underlain by outwash 
 sands. Two soils occur in this outwash area, Brenton Silt Loam and Drummer 
 Clay Loam. Catlin Silt Loam occurs on the highest parts of the field and 
 Flanagan Silt Loam on the lower parts of the slopes bordering the outwash. 
 
 The other field used in 1943, 1944, and 1945 consists mainly of Flanagan Silt 
 Loam, while the field used in the 1946 tests is composed of Drummer Clay Loam. 
 
 The agricultural ratings of these soils are: Thorp 4-5; Flanagan 2; Brenton 
 2; and Drummer 1. The number indicates the ability of the soil type to produce 
 the major crops grown in the region without soil treatment but with the soil 
 cleared and drained. The scale is 1 to 10, the most productive soil in the state 
 being rated 1 and the least productive 10. 
 
1949} YIELDS OF CORN HYBRIDS HARVESTED FOR SILAGE 369 
 
 to use a machine which harvests and chops the forage in one opera- 
 tion. The blocks ranged from about 77 to 97 rods long; a single block 
 comprised about 10 acres. Each block was surrounded by a 20-foot 
 border of late-planted soybeans harvested prior to corn harvest or 
 by a 20-foot border kept fallow. 
 
 Twelve hybrids were grown each season. They were given entry 
 numbers of 1 to 12 to facilitate plot numbering and record keeping. 
 In Block 1 four rows (one round with a two-row planter) of Entry 1 
 were planted at one side of the field. Four rows of Entry 2 were 
 planted next to Entry 1. Entry 2 was then followed by four rows of 
 each of the other entries until each of the twelve entries had been 
 planted. Then four rows of Entry 11 were planted followed by four 
 rows each of Entries 10, 9, 8, etc. This planting system provided four 
 rows of Entry 1 at each side of the field, making it practicable to 
 harvest the forage with a machine which was best operated by circling 
 the entire block. A further advantage of the planting system was that 
 each hybrid except the one in the middle of the block grew in two 
 separate parts of the field. 
 
 Five complete blocks, or replications, were grown each season 
 except in 1942, when there were six replications. When the planting of 
 Block 1 was completed, a randomized system of planting the remaining 
 blocks was followed. This system provided for a rearrangement of the 
 order of planting the entries, a different order being used in each block. 
 In this manner the effects of being on the border and the possible 
 influences of one entry on an adjoining one were minimized. The 
 planting plan provided a suitable basis for a statistical analysis of the 
 yield data. 
 
 Measuring Forage Yields 
 
 Field sampling. One method of measuring forage yields for silage 
 was field sampling: the yields were calculated from the weight and 
 dry-matter content of representative samples of the standing corn. 
 
 Field samples were usually taken just before the corn was harvested 
 for silo filling. Samples of each entry were taken from rows planted 
 by each of the boxes of the planter. The samples consisted of every 
 hundredth plant from two rows, each row about 77 or 97 rods long. 
 
 The samples were obtained by teams of two men each. The first 
 man counted the plants and cut the plant to be used for sampling close 
 to the ground. The second checked the count with a mechanical hand 
 tally and carried the harvested plants. 
 
 The number of plants per row was carefully recorded. In some 
 
368 
 
 BULLETIN No. 533 
 
 [April, 
 
 Table 1. Pedigrees of Illinois and U. S. Hybrids Tested for Yields of 
 
 Forage for Silage 
 
 Hybrid 
 
 Pedigree 
 
 Hybrid 
 
 Pedigree 
 
 111. 21 (WF9 X 38-11) (187-2 X Hy) 
 
 111. 126 (WF9 X 38-11) (Tr X L317) 
 
 111. 200 (WF9 X 38-11) (K4 X L317) 
 
 111. 201 (WF9 X 38-11) (187-2 X L317) 
 
 111. 206 (WF9 X 38-11) (5120 X L317) 
 
 111. 246 (WF9 X Hy) (187-2 X L317) 
 
 111. 246A-1 (WF9 X 187-2) (Hy X R57) 
 
 111. 247 (187-2 X 38-11) (Hy X L317) 
 
 111. 247-1 (187-2 X 38-11) (Hy X R57) 
 
 111. 273 (WF9 X 38-11) (l'87-2 X 701) 
 
 111. 448 (38-11 X Kys) (K4 X L317) 
 
 111. 713 (WF9 X 38-11) (G X L317) 
 
 111. 784 (Hy X 5120) (K4 X L317) 
 
 111. 801 (5120 X Kys) (K4 X L317) 
 
 111. 804 (5120 X 38-11) (K4 X L317) 
 
 111. 838 (38-11 X Pr) (K4 X L317) 
 
 111. 855 (R4 X Hy) (G X L317) 
 
 111. 863 (R4 X Hy) (K4 X L317) 
 
 111. 877 (R4 X Pr) (K4 X L317) 
 
 111. 972 (WF9 X Hy) (701 X L317) 
 
 111. 972A-1 (WF9 X O7) (Hy X 1,317) 
 
 111. 972-2 (WF9 X Hy) (07 X R57) 
 
 111. 2059(W). . . (Ky27 X CI.61) (33-16 X K6) 
 111. 2077(W) . . . (33-16 X CI.61) (Ky27 X CI.43) 
 111. 2119(W) . . . (Ky27 X CI.61) (33-16 X K64) 
 U.S. 13 (Hy X L317) (WF9 X 38-11) 
 
 (1943-1946) on Station land at Urbana. 1 Hybrids which have excellent 
 grain production records were chosen for these tests. 
 
 It was shown in the first of these studies (1935-1941, reported in 
 Bulletin 494) that hybrid corn was superior to open-pollinated in pro- 
 duction of forage. Therefore the use of an open-pollinated variety as a 
 standard, or check, was discontinued and a well-known and widely 
 grown hybrid, U. S. 13, was used in its place. Studies were made of 25 
 Illinois hybrids. The pedigrees of these hybrids are given in Table 1. 
 
 "Block" Plan of Planting Used 
 
 The land on which the corn was grown was prepared for planting 
 by either fall or spring plowing, followed by disking, harrowing, and 
 if necessary rolling to give a good seedbed. The seed was drilled in 
 rows 3.5 feet apart. The corn was cultivated first with a rotary hoe 
 and later with a shovel cultivator. 
 
 A "block" plan of planting was followed in order to make it easier 
 
 1 The field used in the 1942 tests contains a combination of Flanagan and 
 Thorp Silt Loams and Drummer Clay Loam. The field is level. Drainage on the 
 Thorp Silt Loam is slow because of the character of the subsoil. 
 
 One of the two fields used in 1943, 1944, and 1945 is underlain by outwash 
 sands. Two soils occur in this outwash area, Brenton Silt Loam and Drummer 
 Clay Loam. Catlin Silt Loam occurs on the highest parts of the field and 
 Flanagan Silt Loam on the lower parts of the slopes bordering the outwash. 
 
 The other field used in 1943, 1944, and 1945 consists mainly of Flanagan Silt 
 Loam, while the field used in the 1946 tests is composed of Drummer Clay Loam. 
 
 The agricultural ratings of these soils are: Thorp 4-5; Flanagan 2; Brenton 
 2; and Drummer 1. The number indicates the ability of the soil type to produce 
 the major crops grown in the region without soil treatment but with the soil 
 cleared and drained. The scale is 1 to 10, the most productive soil in the state 
 being rated 1 and the least productive 10. 
 
1949] YIELDS OF CORN HYBRIDS HARVESTED FOR SILAGE 369 
 
 to use a machine which harvests and chops the forage in one opera- 
 tion. The blocks ranged from about 77 to 97 rods long; a single block 
 comprised about 10 acres. Each block was surrounded by a 20-foot 
 border of late-planted soybeans harvested prior to corn harvest or 
 by a 20-foot border kept fallow. 
 
 Twelve hybrids were grown each season. They were given entry 
 numbers of 1 to 12 to facilitate plot numbering and record keeping. 
 In Block 1 four rows (one round with a two-row planter) of Entry 1 
 were planted at one side of the field. Four rows of Entry 2 were 
 planted next to Entry 1. Entry 2 was then followed by four rows of 
 each of the other entries until each of the twelve entries had been 
 planted. Then four rows of Entry 11 were planted followed by four 
 rows each of Entries 10, 9, 8, etc. This planting system provided four 
 rows of Entry 1 at each side of the field, making it practicable to 
 harvest the forage with a machine which was best operated by circling 
 the entire block. A further advantage of the planting system was that 
 each hybrid except the one in the middle of the block grew in two 
 separate parts of the field. 
 
 Five complete blocks, or replications, were grown each season 
 except in 1942, when there were six replications. When the planting of 
 Block 1 was completed, a randomized system of planting the remaining 
 blocks was followed. This system provided for a rearrangement of the 
 order of planting the entries, a different order being used in each block. 
 In this manner the effects of being on the border and the possible 
 influences of one entry on an adjoining one were minimized. The 
 planting plan provided a suitable basis for a statistical analysis of the 
 yield data. 
 
 Measuring Forage Yields 
 
 Field sampling. One method of measuring forage yields for silage 
 was field sampling: the yields were calculated from the weight and 
 dry-matter content of representative samples of the standing corn. 
 
 Field samples were usually taken just before the corn was harvested 
 for silo filling. Samples of each entry were taken from rows planted 
 by each of the boxes of the planter. The samples consisted of every 
 hundredth plant from two rows, each row about 77 or 97 rods long. 
 
 The samples were obtained by teams of two men, each. The first 
 man counted the plants and cut the plant to be used for sampling close 
 to the ground. The second checked the count with a mechanical hand 
 tally and carried the harvested plants. 
 
 The number of plants per row was carefully recorded. In some 
 
372 
 
 BULLETIN No. 533 
 
 [April, 
 
 Table 2. Dry-Matter Yields of Corn Harvested for Silage, Test 
 
 Weights of Dry Grain, Proportion of Erect Plants, 1942-1944, 
 
 1946; and Number of Ears per Plant, 1945 
 
 (Figures showing dry matter are in tons per acre) 
 
 Dry Test 
 Dry matter in field samples* matter weight 
 
 Weight 
 of Erect 
 500 plants* 
 ker- 
 nels* 
 
 Ears* 
 
 Stalks Leaves Total vested per 
 forage b bushel* 
 
 1942: A difference between any two entries of less than .397 ton 
 of dry matter in harvested forage is not significant. 
 
 
 tons 
 
 tons 
 
 tons 
 
 tons 
 
 tons 
 
 Ib. 
 
 grams 
 
 perct. 
 
 Illinois 200 
 
 .93 
 
 .78 
 
 .63 
 
 2.34 
 
 3.24 
 
 53.9 
 
 93 
 
 97.6 
 
 Illinois 801 
 
 57 
 
 .99 
 
 .76 
 
 2.32 
 
 3.21 
 
 51.3 
 
 77 
 
 96.9 
 
 Illinois 206 
 
 1.11 
 
 .82 
 
 .65 
 
 2.58 
 
 3.20 
 
 54.0 
 
 97 
 
 97.7 
 
 Illinois 448 
 
 67 
 
 1.06 
 
 .79 
 
 2.52 
 
 3.12 
 
 53.7 
 
 85 
 
 97.1 
 
 Illinois 784 
 
 87 
 
 1.04 
 
 .76 
 
 2.67 
 
 2.96 
 
 53.0 
 
 85 
 
 96.1 
 
 Illinois 201 
 
 91 
 
 .64 
 
 .58 
 
 2.13 
 
 2.95 
 
 53.3 
 
 93 
 
 96.7 
 
 Illinois 838 
 
 .93 
 
 1.00 
 
 .73 
 
 2.66 
 
 2.92 
 
 54.8 
 
 89 
 
 94.9 
 
 Illinois 21 
 
 1.07 
 
 .87 
 
 .62 
 
 2.55 
 
 2.92 
 
 54.6 
 
 98 
 
 97.4 
 
 U.S. 13 
 
 1.04 
 
 .72 
 
 .57 
 
 2.33 
 
 2.83 
 
 55.8 
 
 105 
 
 95.6 
 
 Illinois 804 
 
 97 
 
 .87 
 
 .71 
 
 2.55 
 
 2.81 
 
 55.2 
 
 94 
 
 94.5 
 
 Illinois 247 
 
 ... 1.09 
 
 .90 
 
 .64 
 
 2.63 
 
 2.80 
 
 55.0 
 
 99 
 
 97.8 
 
 Illinois 126 
 
 98 
 
 .83 
 
 .57 
 
 2.38' 
 
 2.59 
 
 52.9 
 
 91 
 
 95.9 
 
 All entries, average 
 
 .93 
 
 .88 
 
 .67 
 
 2.47 
 
 2.96 
 
 54.0 
 
 92 
 
 96.5 
 
 1943: A difference between any two entries of less than .447 ton 
 of dry matter in harvested forage is not significant. 
 
 Illinois 713 
 
 . 2 
 
 .53 
 
 1.18 
 
 1.11 
 
 4 
 
 82 
 
 4 
 
 .48 
 
 53.3 
 
 108 
 
 99.0 
 
 Illinois 863 
 
 2 
 
 61 
 
 1.26 
 
 1.13 
 
 5 
 
 00 
 
 4 
 
 .34 
 
 55.0 
 
 95 
 
 93.9 
 
 Illinois 206 
 
 2 
 
 .79 
 
 1.32 
 
 1.04 
 
 5 
 
 15 
 
 4 
 
 33 
 
 57.1 
 
 126 
 
 98.3 
 
 Illinois 200 
 
 2 
 
 64 
 
 1.26 
 
 1.13 
 
 5, 
 
 03 
 
 4 
 
 30 
 
 56.1 
 
 110 
 
 98.5 
 
 Illinois 784 
 
 2 
 
 27 
 
 1.22 
 
 1.04 
 
 4. 
 
 53 
 
 4 
 
 28 
 
 55.5 
 
 102 
 
 98.0 
 
 U. S. 13 
 
 2. 
 
 64 
 
 1.24 
 
 1.01 
 
 4. 
 
 89 
 
 4 
 
 22 
 
 55.6 
 
 117 
 
 99.1 
 
 Illinois 838 
 
 2 
 
 36 
 
 1.33 
 
 1.17 
 
 4 
 
 86 
 
 4 
 
 .21 
 
 54.9 
 
 101 
 
 98.1 
 
 Illinois 246 
 
 2 
 
 55 
 
 1.18 
 
 .90 
 
 4 
 
 63 
 
 4 
 
 .14 
 
 56.2 
 
 120 
 
 98.9 
 
 Illinois 247 
 
 2 
 
 51 
 
 1.13 
 
 .98 
 
 4. 
 
 62 
 
 4 
 
 06 
 
 55.3 
 
 105 
 
 98.5 
 
 Illinois 201 
 
 2. 
 
 63 
 
 1.22 
 
 1.04 
 
 4. 
 
 89 
 
 4 
 
 01 
 
 55.3 
 
 111 
 
 98.9 
 
 Illinois 448 
 
 2. 
 
 29 
 
 1.36 
 
 1.22 
 
 4. 
 
 87 
 
 3 
 
 97 
 
 53.9 
 
 82 
 
 97.4 
 
 Illinois 21 
 
 2 
 
 54 
 
 1.27 
 
 1.11 
 
 4. 
 
 92 
 
 3 
 
 92 
 
 54.7 
 
 110 
 
 99.3 
 
 All entries, average 2 . 53 1 . 25 
 
 1.07 
 
 4.85 
 
 4.19 
 
 55.2 
 
 107 
 
 98.2 
 
 1944: A difference between any two entries of less than .273 ton 
 of dry matter in harvested forage is not significant. 
 
 Illinois 784 
 
 1.59 
 
 1.41 
 
 1.12 
 
 4 
 
 1? 
 
 4 
 
 66 
 
 
 
 
 80 4 
 
 Illinois 804 
 
 1.67 
 
 1.42 
 
 1.10 
 
 4 
 
 19 
 
 4 
 
 59 
 
 
 
 
 85 5 
 
 Illinois 863 
 
 1.71 
 
 1.46 
 
 .98 
 
 4 
 
 15 
 
 4 
 
 56 
 
 
 
 
 77 8 
 
 Illinois 206 
 
 1.82 
 
 1.34 
 
 1.01 
 
 4 
 
 17 
 
 4 
 
 48 
 
 
 
 
 86 7 
 
 Illinois 448 
 
 1.26 
 
 1.56 
 
 1.11 
 
 3 
 
 93 
 
 4 
 
 46 
 
 
 
 
 87 
 
 U. S. 13 
 
 1.76 
 
 1.20 
 
 1.00 
 
 3 
 
 96 
 
 4 
 
 43 
 
 
 
 
 89.8 
 
 Illinois 713 
 
 1.61 
 
 1 26 
 
 1.21 
 
 4 
 
 08 
 
 4 
 
 29 
 
 
 
 
 91 5 
 
 Illinois 201 
 
 1.88 
 
 1.27 
 
 1.01 
 
 4 
 
 16 
 
 4 
 
 28 
 
 
 
 
 89 4 
 
 Illinois 972 
 
 2.00 
 
 1.36 
 
 1.22 
 
 4 
 
 58 
 
 4 
 
 24 
 
 
 
 
 75 3 
 
 Illinois 273 
 
 ... 1.77 
 
 1.19 
 
 .98 
 
 3 
 
 Q4 
 
 4 
 
 20 
 
 
 
 
 93 3 
 
 Illinois 2077 (W) 
 
 ... 1.37 
 
 1.48 
 
 1.07 
 
 3 
 
 9? 
 
 4 
 
 20 
 
 
 
 
 82 4 
 
 Illinois 855 . . . 
 
 1.34 
 
 1.41 
 
 1.13 
 
 3 
 
 88 
 
 4 
 
 08 
 
 
 
 
 89.6 
 
 All entries, average 
 
 1.64 
 
 1.36 1.08 
 
 4.09 
 
 4.37 
 
 85.7 
 
 (Table is concluded on next page.) 
 
1949} YIELDS OF CORN HYBRIDS HARVESTED FOR SILAGE 373 
 
 Table 2. Dry-Matter Yields of Corn Harvested for Silage concluded 
 
 (Figures showing dry matter are in tons per acre) 
 
 Dry matter in field samples* 
 
 Dry 
 
 matter 
 
 Test 
 weight 
 of grain 
 per 
 bushel" 
 
 Weight 
 of 
 500 
 ker- 
 nels" 
 
 Ears 
 per 
 plant" 
 
 Ears" 
 
 Stalks 
 
 Leaves 
 
 Total 
 
 vested 
 forage b 
 
 1945: A difference between any two entries of less than .386 ton 
 of dry matter in harvested forage is not significant. 
 
 Illinois 2119(W). . 
 
 tons 
 1 31 
 
 tons 
 1.65 
 
 tons 
 1.08 
 
 tons 
 4.04 
 
 tons 
 4.65 
 
 Ib. 
 38 7 
 
 grams 
 63 
 
 1 27 
 
 Illinois 448. 
 
 1.29 
 
 1.71 
 
 1.22 
 
 4.22 
 
 4.57 
 
 40.1 
 
 57 
 
 1 21 
 
 Illinois 206 
 
 1.61 
 
 1.31 
 
 .93 
 
 3.85 
 
 4.57 
 
 44.9 
 
 71 
 
 1 34 
 
 Illinois 200 
 
 1.59 
 
 1.47 
 
 1.06 
 
 4.12 
 
 4.56 
 
 43 5 
 
 76 
 
 1 26 
 
 Illinois 877. 
 
 . . 1 . 60 
 
 1.51 
 
 1.35 
 
 4.46 
 
 4.48 
 
 44.5 
 
 65 
 
 1 45 
 
 Illinois 784 
 
 1.34 
 
 1.55 
 
 1.08 
 
 3.97 
 
 4.48 
 
 41.4 
 
 59 
 
 1 14 
 
 U. S. 13 
 
 1.62 
 
 1.49 
 
 1.03 
 
 4.14 
 
 4.42 
 
 45.3 
 
 82 
 
 1 08 
 
 Illinois 2059 (W) 
 
 1 37 
 
 1 50 
 
 98 
 
 3 85 
 
 4.42 
 
 37 8 
 
 69 
 
 1 25 
 
 Illinois 2077 (W) 
 
 1.48 
 
 1.79 
 
 1.16 
 
 4.43 
 
 4.28 
 
 37 2 
 
 64 
 
 1 09 
 
 Illinois 126. 
 
 1 . 64 
 
 1.24 
 
 .96 
 
 3.84 
 
 4.28 
 
 47.2 
 
 78 
 
 1 13 
 
 Illinois 804 
 
 1.61 
 
 1.64 
 
 1.00 
 
 4.25 
 
 4.23 
 
 46.8 
 
 71 
 
 1 33 
 
 Illinois 972-2. . 
 
 1.52 
 
 1.32 
 
 .97 
 
 3.81 
 
 4.07 
 
 45.5 
 
 78 
 
 1.15 
 
 All entries, average 1.50 1.52 1.07 4.08 4.58 42.7 69 1.23 
 
 1946: A difference between any two entries of less than .412 ton 
 of dry matter in harvested forage is not significant. 
 
 Illinois 877.. . 
 
 . 2 
 
 1? 
 
 1.44 
 
 1.11 
 
 4 
 
 67 
 
 4.72" 
 
 54 
 
 
 
 109 
 
 (Erect 
 plants") 
 perct. 
 70 7 
 
 U. S. 13 
 
 2 
 
 3? 
 
 1.45 
 
 1.18 
 
 4 
 
 94 
 
 4.55<i 
 
 53 
 
 5 
 
 114 
 
 78.8 
 
 Illinois 972A-1 
 
 2 
 
 ,20 
 
 1.40 
 
 1.10 
 
 4 
 
 .60 
 
 4.48d 
 
 54 
 
 7 
 
 112 
 
 72 3 
 
 Illinois 247-1 
 
 1 
 
 8? 
 
 1.53 
 
 1.02 
 
 4 
 
 41 
 
 4.38 C 
 
 5? 
 
 3 
 
 109 
 
 74 1 
 
 Illinois 126 
 
 2 
 
 06 
 
 1.59 
 
 1.29 
 
 4 
 
 94 
 
 4.37 d 
 
 50 
 
 ? 
 
 88 
 
 70.6 
 
 Illinois 246A-1 
 
 1 
 
 80 
 
 1.64 
 
 1.01 
 
 4 
 
 45 
 
 4.35 C 
 
 45 
 
 3 
 
 95 
 
 49 1 
 
 Illinois 21 
 
 1 
 
 70 
 
 1 72 
 
 1 19 
 
 4 
 
 61 
 
 4 28 d 
 
 50 
 
 
 
 115 
 
 52 7 
 
 Illinois 2077(W). . . 
 
 2 
 
 .16 
 
 1.43 
 
 1.01 
 
 4 
 
 60 
 
 4.28 d 
 
 54 
 
 3 
 
 103 
 
 72 4 
 
 Illinois 448 
 
 2 
 
 07 
 
 1.34 
 
 .92 
 
 4 
 
 33 
 
 4.26" 
 
 5? 
 
 8 
 
 112 
 
 69.5 
 
 Illinois 2119(W). . . 
 
 1 
 
 66 
 
 2.01 
 
 1 46 
 
 5 
 
 13 
 
 4.21'' 
 
 48 
 
 8 
 
 78 
 
 50 4 
 
 Illinois 784 
 
 ... 1 
 
 .71 
 
 1.60 
 
 1.26 
 
 4 
 
 57 
 
 4.14 
 
 47 
 
 
 
 101 
 
 44 8 
 
 Illinois 2059 (W).. 
 
 . 2 
 
 09 
 
 1.68 
 
 1.20 
 
 4 
 
 97 
 
 4.07d 
 
 52 
 
 7 
 
 99 
 
 68.0 
 
 All entries, average 1.98 1.57 1.15 4.69 4.34 51.3 103 64.5 
 
 a Means of three replications. (In 1942 only the grain was included in the analysis of the 
 dry matter in the field samples.) b Forage yields in 1942 are the means of six replications; those 
 in 1943, 1944, and 1945 are the means of five replications. c Means of five replications in 1946. 
 d Means of four replications in 1946. 
 
 Yields of forage and ears not directly related. At the silage- 
 harvesting stage there is no direct relation between the yield of dry 
 matter in harvested forage and the proportion of dry matter formed by 
 the ears. For example, Illinois 246A-1 was slightly above the average, 
 while Illinois 21, 784, and 2119(W) were nearly equal to it in yield 
 of forage (Table 2, 1946) , but the proportion of ears in their forage 
 was lower than that of the other entries (Table 3, 1946). It is thus 
 evident that some late-maturing hybrids produce satisfactory yields 
 of forage. Their feeding value per ton, however, is likely to be less than 
 that of forage containing a high proportion of ears. Moreover, in 
 
374 
 
 BULLETIN No. 533 
 
 [April, 
 
 Table 3. Dry-Matter Content of Ear, Stalk, and Leaf at Time Crop 
 
 Was Harvested for Silage, and Proportion Each Part of the Plant 
 
 Contributed to Total Crop 
 
 (Expressed in percentage) 
 
 Entry 
 
 Dry matter in sample 
 
 Proportion of dry matter 
 of crop in 
 
 Ear 
 
 Stalk 
 
 Leaf 
 
 Crop 
 
 Ears 
 
 Stalks 
 
 Leaves 
 
 1942 
 
 U S 13 
 
 33 
 
 
 .9 
 .1 
 6 
 5 
 
 
 ,1 
 9 
 1 
 9 
 ,7 
 4 
 
 ,8 
 
 20.7 
 20.5 
 21.5 
 22.7 
 21.3 
 22.4 
 
 21.5 
 20.5 
 23.2 
 22.6 
 22.8 
 22.2 
 
 21.8 
 
 25.9 
 24.5 
 27.4 
 24.9 
 26.2 
 26.8 
 
 25.8 
 26.1 
 27.1 
 28.7 
 25.2 
 25.3 
 
 26.2 
 
 26 
 25 
 27 
 26 
 26 
 26 
 
 25 
 25 
 27 
 26 
 23 
 23. 
 
 26 
 
 3 
 
 .8 
 ,2 
 
 .7 
 5 
 8 
 
 .8 
 7 
 
 6 
 9 
 2 
 
 
 
 44.6 
 43.0 
 42.7 
 41.8 
 41.5 
 41.2 
 
 39.8 
 38.0 
 35.0 
 32.6 
 26.6 
 24.6 
 
 37.6 
 
 30 
 31 
 30 
 34 
 34 
 34 
 
 33 
 34 
 37 
 39 
 42 
 42 
 
 35 
 
 ,9 
 .8 
 .0 
 
 2 
 9 
 
 3 
 
 .1 
 6 
 
 1 
 
 .7 
 
 ,4 
 
 24.5 
 25.2 
 27.2 
 24.2 
 24.3 
 23.9 
 
 26.9 
 27.9 
 27.4 
 28.4 
 31.3 
 32.7 
 
 27.0 
 
 Illinois 206 
 
 32 
 
 Illinois 201 . 
 
 . . 33 
 
 Illinois 21 
 
 32 
 
 Illinois 247 
 
 33 
 
 Illinois 126 . 
 
 31 
 
 Illinois 200 
 
 . 31 
 
 Illinois 804 
 
 32 
 
 Illinois 838 
 
 ... .32 
 
 Illinois 784 
 
 30 
 
 Illinois 448 
 
 23 
 
 Illinois 801 
 
 . 22, 
 
 
 30 
 
 
 
 1943 
 
 Illinois 246 
 
 47 
 
 .4 
 .3 
 .4 
 6 
 4 
 2 
 
 2 
 
 .2 
 
 8 
 4 
 
 
 ,8 
 
 20.5 
 19.8 
 19.8 
 20.0 
 20.3 
 19.7 
 
 19.2 
 19.1 
 20.2 
 19.7 
 19.7 
 20.0 
 
 19.8 
 
 28.2 
 27.3 
 28.7 
 29.9 
 27.7 
 28.2 
 
 26.0 
 27.6 
 28.1 
 27.7 
 26.1 
 27.4 
 
 27.7 
 
 31 
 30 
 31 
 31 
 31 
 30 
 
 29 
 30 
 30 
 30 
 28 
 28 
 
 30 
 
 .7 
 .4 
 3 
 .1 
 
 2 
 
 2 
 1 
 5 
 7 
 5 
 3 
 
 3 
 
 55 
 54 
 54 
 54 
 53 
 52 
 
 52 
 52 
 51 
 50 
 
 48 
 47 
 
 52 
 
 .1 
 .3 
 .2 
 .0 
 ,8 
 .5 
 
 .5 
 .2 
 .6 
 .1 
 .6 
 .0 
 
 .2 
 
 25 
 24 
 25 
 25 
 25 
 25 
 
 24 
 25 
 25 
 26 
 27 
 27 
 
 25 
 
 5 
 .5 
 
 .6 
 ,4 
 
 1 
 
 5 
 2 
 8 
 9 
 4 
 9 
 
 ,7 
 
 19.4 
 21.2 
 20.2 
 20.7 
 21.3 
 22.5 
 
 23.0 
 22.6 
 22.6 
 23.0 
 24.1 
 25.0 
 
 22.1 
 
 Illinois 247 
 
 44 
 
 Illinois 206 
 
 47 
 
 U S 13 
 
 44 
 
 Illinois 201 
 
 45 
 
 Illinois 200 
 
 44 
 
 Illinois 713 
 
 43 
 
 Illinois 863 
 
 46 
 
 Illinois 21 
 
 45 
 
 Illinois 784 
 
 47 
 
 Illinois 838 
 
 42 
 
 Illinois 448 
 
 40, 
 
 
 44 
 
 
 
 1944 
 
 Illinois 201 
 
 35 
 
 .9 
 .1 
 ,8 
 6 
 ,6 
 ,5 
 
 4 
 .1 
 9 
 8 
 4 
 ,7 
 
 
 
 18.9 
 17.5 
 18.1 
 19.6 
 19.2 
 17.1 
 
 18.0 
 18.0 
 18.9 
 19.2 
 20.7 
 18.4 
 
 18.6 
 
 25.7 
 24.5 
 27.8 
 23.1 
 26.5 
 22.3 
 
 23.7 
 24.1 
 27.4 
 22.5 
 22.2 
 23.4 
 
 24.4 
 
 26 
 25 
 26 
 26 
 26 
 22 
 
 24 
 24 
 26 
 23. 
 24, 
 22 
 
 24 
 
 .2 
 3 
 
 .7 
 3 
 7 
 9 
 
 1 
 2 
 
 5 
 
 5 
 
 9 
 
 45.2 
 
 44.9 
 44.4 
 43.7 
 43.7 
 41.2 
 
 39.9 
 39.4 
 38.6 
 34.9 
 34.5 
 32.1 
 
 40.2 
 
 30 
 30 
 30 
 29 
 32 
 35 
 
 33 
 30 
 34. 
 37. 
 36 
 39. 
 
 33 
 
 ,5 
 ,2 
 3 
 .7 
 1 
 2 
 
 9 
 9 
 2 
 8 
 4 
 7 
 
 4 
 
 24.3 
 
 24.9 
 25.3 
 26.6 
 24.2 
 23.6 
 
 26.2 
 29.7 
 27.2 
 27.3 
 29.1 
 28.2 
 
 26.4 
 
 Illinois 273 
 
 37 
 
 U. S. 13 
 
 37 
 
 Illinois 972 
 
 38 
 
 Illinois 206 
 
 37 
 
 Illinois 863 
 
 33 
 
 Illinois 804 
 
 34 
 
 Illinois 713 
 
 33 
 
 Illinois 784 
 
 36 
 
 Illinois 2077 (W) . . 
 
 32 
 
 
 32, 
 
 Illinois 448 
 
 29 
 
 
 ... 35 
 
 
 
 a In 1942 only the grain was included. 
 
 (Table is concluded on next page.) 
 
1949} YIELDS OF CORN HYBRIDS HARVESTED FOR SILAGE 375 
 
 Table 3. Dry-Matter Content of Ear, Leaf, and Stalk concluded 
 
 (Expressed in percentage) 
 
 Dry matter in sample ^^ofTro^ f n r L matter 
 Ear Stalk Leaf Crop Eafs ^te Leaves 
 
 1945 
 
 Illinois 126 
 
 . 42.1 
 
 19.4 
 
 25.0 
 
 27.1 
 
 42.7 
 
 32.3 
 
 25.0 
 
 Illinois 206 
 
 38.2 
 
 19.1 
 
 25.1 
 
 26.0 
 
 41.8 
 
 34.0 
 
 24.2 
 
 Illinois 972-2 
 
 40.7 
 
 20.7 
 
 26.7 
 
 27.7 
 
 39.9 
 
 34.6 
 
 25.5 
 
 U.S. 13 
 
 39.8 
 
 20.2 
 
 26.7 
 
 27.0 
 
 39.1 
 
 36.0 
 
 24.9 
 
 Illinois 200 
 
 36.1 
 
 19.5 
 
 24.0 
 
 25.2 
 
 38.6 
 
 35.7 
 
 25.7 
 
 Illinois 804 
 
 38.1 
 
 20.9 
 
 24.9 
 
 26.4 
 
 37.9 
 
 38.6 
 
 23.5 
 
 Illinois 877 
 
 . 34.2 
 
 18.7 
 
 26.2 
 
 24.9 
 
 35.9 
 
 33.9 
 
 30.2 
 
 Illinois 2059 (W) 
 
 30.3 
 
 19.7 
 
 24.9 
 
 23.9 
 
 35.6 
 
 39.0 
 
 25.4 
 
 Illinois 784 
 
 34.2 
 
 18.9 
 
 25.2 
 
 24.1 
 
 33.8 
 
 39.0 
 
 27.2 
 
 Illinois 2077 (W) 
 
 35.8 
 
 20.5 
 
 23.5 
 
 24.9 
 
 33.4 
 
 40.4 
 
 26.2 
 
 Illinois 211 9 (W) 
 
 35.0 
 
 21.3 
 
 25.5 
 
 25.7 
 
 32.4 
 
 40.9 
 
 26.7 
 
 Illinois 448 
 
 30.2 
 
 19.9 
 
 23.8 
 
 23.4 
 
 30.6 
 
 40.5 
 
 28.9 
 
 All entries, average 
 
 36.2 
 
 19.9 
 
 25.1 
 
 25.5 
 
 36.8 
 
 37.1 
 
 26.1 
 
 1946 
 
 Illinois 448 
 
 . 40 
 
 .7 
 
 20.1 
 
 23.8 
 
 27 
 
 7 
 
 47 
 
 8 
 
 30 
 
 7 
 
 21.5 
 
 U. S. 13 
 
 40 
 
 .fi 
 
 19.4 
 
 25.8 
 
 27 
 
 ,8 
 
 47 
 
 
 
 29 
 
 3 
 
 23.7 
 
 Illinois 2077 (W) 
 
 41 
 
 .8 
 
 19.7 
 
 25.6 
 
 28 
 
 .1 
 
 46 
 
 ,8 
 
 31 
 
 .0 
 
 22.2 
 
 Illinois 972A-1 
 
 39 
 
 fi 
 
 18.5 
 
 24.3 
 
 26 
 
 
 
 46 
 
 7 
 
 30 
 
 
 
 23.3 
 
 Illinois 247-1 
 
 35 
 
 ,1 
 
 20.3 
 
 25.3 
 
 26 
 
 1 
 
 46. 
 
 5 
 
 31 
 
 8 
 
 21.7 
 
 Illinois 877 
 
 40 
 
 1 
 
 21.6 
 
 25.1 
 
 28, 
 
 4 
 
 42. 
 
 1 
 
 36 
 
 1 
 
 21.8 
 
 Illinois 2059 (W) 
 
 . 41 
 
 .6 
 
 20.5 
 
 26.2 
 
 27 
 
 9 
 
 41. 
 
 6 
 
 34 
 
 4 
 
 24.0 
 
 Illinois 126 
 
 38 
 
 .5 
 
 19.5 
 
 25.4 
 
 26 
 
 6 
 
 41 
 
 4 
 
 32 
 
 3 
 
 26.3 
 
 Illinois 246A-1 
 
 39. 
 
 3 
 
 21.7 
 
 23.4 
 
 27 
 
 1 
 
 38. 
 
 1 
 
 38 
 
 ?, 
 
 23.7 
 
 Illinois 21 
 
 38 
 
 .2 
 
 20.9 
 
 22.7 
 
 25 
 
 7 
 
 37 
 
 
 
 37 
 
 2 
 
 25.8 
 
 Illinois 784 
 
 37 
 
 ,2 
 
 20.6 
 
 23.9 
 
 25 
 
 9 
 
 33. 
 
 fi 
 
 36 
 
 7 
 
 29.7 
 
 Illinois 2119(W) 
 
 32 
 
 4 
 
 21.1 
 
 25.7 
 
 25. 
 
 2 
 
 31. 
 
 9 
 
 39, 
 
 5 
 
 28.6 
 
 All entries, average 38.8 20.2 24.8 26.9 41.7 33.9 24.3 
 
 seasons of early frost the crop left after silos have been filled may not 
 produce mature grain. (For further discussion of the desirability of 
 hybrids that yield large amounts of grain, see pages 378-379.) 
 
 Yield of ears. The yields of ears of the various entries indicate 
 that all of the hybrids entered in the 1946 test are potentially high 
 producers of grain (Table 2). Lateness of maturity and inability to 
 develop a full crop of ears at the silage stage is undoubtedly the reason 
 for the relatively lower yield of ears of some of the entries, particularly 
 of Illinois 784 and 2119 (W), which were below average in dry matter 
 at time of harvest. Both these hybrids have performed well in tests of 
 hybrids for grain production. 1 
 
 Field sampling a dependable method of determining forage 
 yields. When corn is grown in drilled rows, field sampling (selecting 
 individual corn plants at random from rows) is a dependable method 
 
 1 See Illinois Station Bulletin 521, "Illinois Hybrid Corn Tests in 1946," issued 
 in 1947. 
 
376 
 
 BULLETIN No. 533 
 
 [April, 
 
 Corn used in these tests was grown on gently rolling land in blocks of 
 about 10 acres. Each block was replicated five to six times. This picture of 
 one such block was taken July 2. 
 
 Corn usually reached the silage stage early in September and yielded 12 to 
 15 tons of forage to the acre. This picture was taken September 8. The 
 block is the same as the one shown in the July 2 picture. 
 
1949] YIELDS OF CORN HYBRIDS HARVESTED FOR SILAGE 377 
 
 of determining yields of forage. This method was compared statistically 
 with yields calculated from the sampling of the completely harvested 
 forage. A comparison of the methods for determining yields of 234 
 plots gave a correlation figure of .865, a figure considered highly 
 significant for the number of comparisons made. 1 
 
 Field sampling has a number of advantages over the usual method 
 of weighing harvested corn forage from an entire plot or a measured 
 portion of a plot. The method is simple, convenient, and quick. It 
 requires only a little equipment; permits a considerable number of 
 plots to be sampled in one day; and the results are ready in a short 
 time. 
 
 Another advantage is that other determinations can be made that 
 are not usually made during harvest. Resistance to lodging can be 
 estimated, and the plants taken for the sample can be measured for 
 height of ear and stalk and proportion of the crop formed by ears, 
 stalks, and blades. Then, too, any one of a number of characteristics 
 of the crop, including percentage of dry matter, yield of forage, and 
 yield of grain, can be followed at regular intervals thruout the season. 
 
 Significance of yield differences. Too much confidence must not 
 be placed in the particular ranking of a hybrid in the following tables, 
 for chance has played a part in determining its position. Unaccount- 
 able variability in the soil and conditions on the field will cause differ- 
 ences in yield that are not inherent in the hybrids themselves. 
 
 The part played by chance in these tests has been calculated for 
 total yield by the mathematical procedure known as "analysis of 
 variance." Above the data for each year in Table 2 is stated the ap- 
 proximate difference which there must be between any two entries in 
 order for them to show a true inherent difference. Unless two hybrids 
 differ by at least this amount, there is no assurance that one hybrid is 
 inherently higher yielding than the other. 
 
 Resistance of Plants to Lodging 
 
 Erect plants best for clean harvest. Because resistance to lodging 
 is a highly desirable characteristic, it was one of the bases used for 
 evaluating entries. Badly lodged plants may result in much loss of the 
 crop. Lodged plants may not develop as fully as erect plants and so 
 cut yields. Moreover, the harvesting machine may fail to gather the 
 down plants. 
 
 1 When 234 pairs of samples are studied, the minimum correlations required 
 for significance are .130 at the 5-percent level and .170 at the 1-percent level. 
 G. W. Snedecor, Statistical Methods, 1938. 
 
378 BULLETIN No. 533 [April, 
 
 In most seasons little lodging occurred in any of the entries, tho 
 in nearly every crop a little corn borer damage caused some broken 
 stalks. In 1944 a severe windstorm caused considerable lodging in one 
 part of the field. Illinois 863 and 972 proved somewhat less resistant 
 to lodging than the other entries in the 1943 and 1944 tests (Table 2) . 
 The strength of all other hybrids tested in these years was satisfactory, 
 as was that of all entries in the other seasons. 
 
 Proportion of Ears in Forage 
 
 The grain of corn forage has a higher feeding value per pound than 
 the stalks or leaves. A high proportion of ears in the forage when it is 
 harvested for silage is therefore a desirable characteristic of any 
 hybrid, and was given careful consideration in the evaluation of the 
 various entries. 
 
 All the hybrids entered in these tests were good producers of grain. 
 There was no conclusive evidence that one was superior to another in 
 the proportion of grain in the forage. Tho differences in this char- 
 acteristic were rather wide, they were caused chiefly by differences 
 in the stage of development reached by the hybrids when they were 
 harvested. The weight of the ears increases rapidly during the later 
 stages of the development of the crop. Hence when early-maturing and 
 late-maturing hybrids were harvested on the same dates, the ears 
 made up a higher proportion of the weight of the dry matter in the 
 early-maturing hybrids than in the late-maturing hybrids. A high 
 proportion of ears in corn forage at the silage stage is obtained by 
 growing hybrids that are well advanced in development when they 
 are harvested. 
 
 In 1943 the average percentage of dry matter in the crop, and the 
 average percentage which the ears contributed to the dry matter, was 
 higher than in the other seasons. There was little difference between 
 entries in these respects (Table 3) . In the other seasons the dry-matter 
 content of the crop was lower. Moreover, the proportion of the crop 
 formed by ears was considerably lower than in 1943 and the entries 
 differed much more widely. 
 
 Ability to Mature Grain 
 
 Silage of good quality depends partly on forage that is mature 
 enough to have a suitable dry-matter content. Hybrids that are in- 
 capable of maturing the grain, or that mature it very late, are likely 
 to produce a sour, soggy silage. Such silage is unpalatable and lower in 
 
1949] YIELDS OF CORN HYBRIDS HARVESTED FOR SILAGE 379 
 
 feeding value than silage made from corn at the right stage of 
 development. 
 
 All the hybrids tested in these trials reached a stage at which the 
 dry-matter content of the crop was high enough for silage. Block plant- 
 ings which remained after the silos had been filled were harvested for 
 grain; the ability of each of the entries to mature the grain proved 
 satisfactory. 
 
 Because late-maturing hybrids yield high in tonnage, farmers 
 sometimes consider them best for silage. Such reasoning is unsound, 
 as earlier trials at this Station showed. 1 The late-maturing hybrids 
 give lower yields of dry matter and make poorer silage than hybrids 
 that are fully matured when harvested. Another disadvantage lies in 
 the inability of late corn to mature grain satisfactorily for grain 
 harvest, so that any of the crop remaining after the silo is filled must 
 either be harvested and fed as fodder or used as soft corn. 
 
 A study of Table 3 will show how the entries used in the later trials 
 compare in earliness of development and percentage of ears. Two 
 hybrids, Illinois 448 and 784, were used in the tests for seven con- 
 secutive years. 1 No. 448 was below average in dry-matter content 
 for five years and below average in proportion of ears in the forage 
 for six years. Illinois 784 was below average in dry-matter content for 
 four years and had less than the average proportion of ears for six 
 years. Both these hybrids are therefore classed as slightly late-matur- 
 ing for central Illinois. U. S. 13, also entered in the trials for seven 
 years, was for six years a little above average in both dry-matter 
 content and proportion of ears. It may therefore be classed as some- 
 what early-maturing for central Illinois. 
 
 Four other hybrids Illinois 21, 200, 201, and 206 were included 
 in the experiment for five years or more. 2 All these were about average 
 in dry-matter content. Illinois 21 was about average in percentage of 
 ears; Illinois 200, 201, and 206 were above average. 
 
 Hybrids Were Similar in Protein Content 
 
 At the silage stage no one hybrid proved superior to another in 
 protein content of forage. The samples selected for analysis were those 
 obtained from the block having forage nearest to 30-percent dry-matter 
 content at the time of harvest. A dry-matter level of 30 percent is 
 considered ideal for corn silage (Illinois Bulletins 391 and 494) . 
 
 1 See Illinois Station Bulletin 391, "Types and Varieties of Corn for Silage," 
 issued in 1933 ; also Bulletin 494, previously cited. 
 
 2 The 1940 and 1941 data were published in Bulletin 494. 
 
380 
 
 BULLETIN No. 533 
 
 [April, 
 
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1949} YIELDS OF CORN HYBRIDS HARVESTED FOR SILAGE 381 
 
 Small differences in protein occurred in individual entries, but there 
 appeared to be no consistent differences between the entries (Table 4) . 
 
 Protein values in 1942 were lower than in the following seasons. 
 These lower values may have been due partly to seasonal differences, 
 tho it is probable that the lower fertility level of the 1942 field was 
 an important factor. Two other factors that affect the protein content 
 of corn forage are the stage of development reached by the ears when 
 the forage is harvested and the proportion of ears in the forage. 
 
 DRY MATTER IN FORAGE BEST INDEX 
 TO HARVEST STAGE 
 
 In general, the higher the dry-matter content of the corn crop the 
 more advanced the crop and the higher the test weight of the grain 
 per bushel and, consequently, the higher the weight of 500 kernels. For 
 example, the 1943 crop had the highest dry-matter content (average 
 of 30.3 percent, Table 3) ; the average test weight of the grain was 
 high, and the weight of 500 kernels was high (Table 2). In 1945 the 
 crop was harvested when the average dry-matter content was only 
 25.5 per cent; and the test weight per bushel and the weight of 500 
 kernels (Table 2) were much lower than in 1943. 
 
 It is not always true, however, that the dry-matter content of the 
 crop indicates the relative development of the grain. In three seasons, 
 1942, 1945, and 1946, the average dry-matter content of the crop at 
 harvest was very similar, being 26.0, 25.5, and 26.9 percent respectively 
 (Table 3) ; but the test weight of the grain and the weight of an equal 
 number of kernels was much smaller in 1945 than in the other two 
 years (Table 2). This observation gives additional support to the 
 recommendation made in previous publications of this Station (Bul- 
 letins 391 and 494) that a determination of the dry-matter content 
 of the forage is a better index of the proper harvest stage than is an 
 estimate of the condition of the ears. 
 
 Leaves are best guide to harvest stage. A study of the dry- 
 matter content of the ear, stalk, and leaf portions of the corn crop 
 showed that when corn is grown under soil and climatic conditions 
 such as those at Urbana, the dry-matter content of the leaves is a good 
 guide to the best time to harvest the crop. These findings confirm 
 those previously reported in Bulletin 494. The most reliable guide, of 
 course, is a determination of the dry-matter content of the entire 
 crop. Such a determination indicates with a high degree of certainty 
 
382 BULLETIN No. 533 [April, 
 
 whether a crop harvested at a given stage will make silage that will 
 keep well. 
 
 In most seasons the leaves and crop had nearly the same average 
 dry-matter content (Table 3). The stalks had a considerably lower 
 percentage of dry matter than the leaves, while the ears had a con- 
 siderably higher percentage. These relationships held good for most 
 of the 180 individual determinations and for the averages of the 60 
 entries. They may not hold good, however, when the dry matter of the 
 crop rises to 35 percent or more, for under such conditions the leaves 
 dry rapidly and may not form a good index to the condition of the crop 
 as a whole. This fact was pointed out in Bulletin 494. 
 
 RATINGS OF TWENTY-SIX HYBRIDS 
 
 The final evaluation of a hybrid requires several years' tests and 
 is dependent on many characteristics. Also, .because of possible year- 
 
 Table 5. Ratings of Corn Hybrids Tested for Their Ability to 
 Produce Forage for Silage 
 
 Rank in 
 
 Ratings for 
 
 Number 
 
 eneral Entry 
 perform- 
 ance 8 
 
 Yield of 
 forage 
 
 Erect 
 plants 
 
 Proportion 
 of grain 
 in forage 
 
 of 
 years 
 grown 
 
 1 
 
 Illinois 206 
 
 4 
 
 10 
 
 7 
 
 6 
 
 2 
 
 Illinois 972A-1 
 
 5 
 
 
 8 
 
 1 
 
 3 
 
 Illinois 863 
 
 1 
 
 14 
 
 14 
 
 4 
 
 4 
 
 U. S. 13 
 
 15 
 
 7 
 
 3 
 
 7 
 
 5 
 
 Illinois 200 
 
 7 
 
 7 
 
 11 
 
 5 
 
 5 
 
 Illinois 713 
 
 10 
 
 4 
 
 10 
 
 4 
 
 7 
 
 Illinois 877 
 
 3 
 
 
 15 
 
 2 
 
 7 
 
 Illinois 247-1 
 
 6 
 
 
 12 
 
 1 
 
 7 
 
 Illinois 246 
 
 19 
 
 5 
 
 1 
 
 1 
 
 10 
 
 Illinois 273 
 
 25 
 
 1 
 
 2 
 
 1 
 
 11 
 
 Illinois 972-2 
 
 19 
 
 
 5 
 
 1 
 
 12 
 
 Illinois 201 
 
 22 
 
 9 
 
 4 
 
 5 
 
 12 
 
 Illinois 247 
 
 24 
 
 3 
 
 o 
 
 2 
 
 14 
 
 Illinois 801 
 
 2 
 
 11 
 
 26 
 
 1 
 
 15 
 
 Illinois 784 
 
 8 
 
 15 
 
 21 
 
 7 
 
 15 
 
 Illinois 838 
 
 10 
 
 13 
 
 20 
 
 4 
 
 17 
 
 Illinois 126 
 
 16 
 
 16 
 
 13 
 
 3 
 
 18 
 
 Illinois 21 
 
 21 
 
 2 
 
 16 
 
 
 
 19 
 
 Illinois 804 
 
 13 
 
 18 
 
 17 
 
 3 
 
 20 
 
 Illinois 448 
 
 12 
 
 12 
 
 22 
 
 7 
 
 21 
 
 Illinois 972. .. 
 
 . 23 
 
 19 
 
 8 
 
 1 
 
 22 
 
 Illinois 21 19(W) 
 
 9 
 
 
 25 
 
 2 
 
 23 
 
 Illinois 2077 (W) 
 
 17 
 
 16 
 
 18 
 
 3 
 
 24 
 
 Illinois 246A-1 
 
 14 
 
 
 22 
 
 1 
 
 25 
 
 Illinois 2059 (W) 
 
 18 
 
 
 19 
 
 2 
 
 26 
 
 Illinois 855 
 
 26 
 
 5 
 
 24 
 
 1 
 
 a The ranking of each hybrid is calculated by allowing 40 percent for its yield-of-forage 
 rating, 20 percent for its erect-plant rating, and 40 percent for proportion-of-grain rating. In 
 the absence of a rating for erect plants, a value of 50 percent was assigned to each of the other 
 ratings. 
 
1949} YIELDS OF CORN HYBRIDS HARVESTED FOR SILAGE 383 
 
 to-year differences in the condition of the seedbed, planting rate, and 
 cultivation, as well as in weather, insect pests, and diseases, a valid 
 comparison of different hybrids is possible only when they are grown 
 in the same seasons. And such a comparison must be based on a 
 statistical analysis of the significance of the yields. 
 
 Final judgment must take into account all the various qualities 
 and values discussed in the preceding sections. Main considerations, 
 however, are: (1) yield of forage; (2) proportion of erect plants; 
 (3) proportion of ears; (4) ability to mature grain; and (5) protein 
 content of the forage. 
 
 The summarized ratings given in Table 5 are based on only three 
 of the above measurements: forage yields, percentage of erect plants, 
 and proportion of ears in the forage. Ability to mature the grain is not 
 included in the table as a rating because it is closely associated with 
 the proportion of ears in the forage, and proportion of ears is a more 
 exact measurement. A rating for protein content is also omitted because 
 the differences in the protein contents of the hybrids tested were so 
 small that a rating based on such differences would be unfair. 
 
 The entries are arranged in Table 5 in the order of their rating 
 for general performance, the one having the best all-round perform- 
 ance, Illinois 206, being given first place. In several instances two or 
 more hybrids have equal numerical ratings, as for example, Illinois 
 200 and Illinois 713. But since Illinois 200 was entered in the tests for 
 five years, it is given precedence over Illinois 713, which was grown 
 only four years. (Note that ratings of ten of the entries are based on 
 the tests reported in Bulletin 494 as well as on the trials reported in 
 this bulletin.) 
 
 SUMMARY AND CONCLUSIONS 
 
 For five seasons, 1942 thru 1946, corn hybrids were tested for their 
 ability to produce forage for silage. The hybrids were grown at Urbana, 
 only those that had shown good performance in grain tests being 
 chosen for the forage tests. 
 
 The yields were determined by two methods. The first consisted 
 of field sampling: the plants in measured rows were counted and a 
 given proportion of them harvested. The weight and dry-matter con- 
 tent of the ear, stalk, and leaf portions of these samples were de- 
 termined. The second method consisted of weighing and sampling the 
 completely harvested crop from measured areas of each entry. The 
 yields were calculated from the weight of the forage and the dry-matter 
 content of the samples. The average results of the two methods were 
 
384 BULLETIN No. 533 
 
 in close agreement, a statistical study of the yields determined by the 
 two methods showing that the field sampling of standing drilled corn 
 is as dependable a means of arriving at yields as the weighing and 
 sampling of a completely harvested crop. 
 
 All of the hybrids entered in the tests proved to be high producers 
 of forage and were satisfactory for silage purposes. Some matured 
 slightly later than others. The ability to mature grain is a desirable 
 characteristic if the crop that is left after silos have been filled is to 
 be harvested for grain. Good lodging resistance (ability of the plants 
 to stand erect) is also ..an essential characteristic of good silage corn. 
 Resistance to lodging was satisfactory in all entries except Illinois 
 863 and 972. 
 
 In proportion of ears, the various entries differed somewhat from 
 season to season. A high proportion of ears is an advantage because 
 the grain has greater feeding value than the leaves and stalks. The 
 stage of development at harvest, as shown by the percentage of dry 
 matter in the forage, was found to be one of the most important 
 determinants of the ear content of the forage. The relationship be- 
 tween stage of development at harvest and ear content of forage was 
 fairly close. Early-maturing hybrids contained a higher percentage 
 of ears at harvest than later-maturing hybrids. 
 
 This study furnishes additional evidence that the leaf portion of 
 corn forage at the silage stage has a dry-matter content nearly the 
 same as that of the entire crop. Hence a dry-matter test of the leaves 
 may be used as an index of the suitability of the crop for silage harvest. 
 
 The protein content of the forage varied from season to season, 
 but none of the hybrids in the trials appeared superior to others in 
 this component. 
 
 Small differences in yield are usually not significant, and the 
 reader is urged to keep this in mind when studying the tables showing 
 yields. 
 
 60504-4940690 
 
UNIVERSITY OF ILLINOIS-URBANA 
 
 Q.6307IL6B C002 
 
 BULLETIN. URBANA 
 529-5401948-50 
 
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