MAIZE 



MAIZE 



423 



plot is aii planted. The planting may tlien be con- 

 tinued for the commercial field, using the same 

 variety of corn, which should be of similar breed- 

 ing, finishing, perhaps, with the multiplying plot 

 on the side of the field opposite from the breeding 

 plot. 



Each one of the breeding plot rows should be 

 numbered to correspond with the " register num- 

 ber " of the ear from which it is planted, as will 

 be explained under the heading of "Register num- 

 ber." The breeding plot should be well protected 

 from foreign pollen, by being planted as far away 

 as possible from other varieties of corn. 



Detasseling. 



Every alternate row of corn in the breeding plot 

 should be completely detasseled before the pollen 

 matures, and all of the seed corn to be taken from 

 the plot should be selected from these forty-eight 

 detasseled rows. This method absolutely prohibits 

 self-pollination or close-pollination of the future 

 seed. By self-pollination is meant the transfer of 

 pollen from the male flower (tassel) of a given 

 plant to the female flower (silk) of the same plant ; 

 by close-pollination, as here used, is meant the 

 transfer of pollen from the male flower of one plant 

 to the female flower of another plant in the same 

 row, both of which grew from kernels from the 

 same seed ear. It is recommended that no plants 



in any of the 

 rows which 

 appear im- 

 perfect, 

 dwarfed, im- 

 mature, bar- 

 ren or other- 

 w i s e unde- 

 sirable, b e 

 allowed to 

 mature pol- 

 len. c c a- 

 sionally, an 

 entire row 

 should be de- 

 tasseled be- 

 cause of the 

 general infe- 

 riority of the 

 row as a 

 whole. These 

 are only pre- 

 cautionary 

 measures 

 needing fur- 

 ther study, 

 while the 

 value of de- 

 tasseling to 

 insure cross-poilination is an established fact. De- 

 tasseling is accomplished Dv going over the rows 

 as many times as mav be necessary and carefully 

 pulling out the tassels as tney appear. Indeed, great 

 care should be exercised in this part of the work 

 in order not to injure the plants and thereby to 

 lower the yields. The tassels should not be cut off, as 



Fig. 646. Showing Initial power of resist- 

 ance to alkali (magnesium carbonate) 

 exUbited in a single wheat plant ; all 

 other plants failed in the same pot. 

 (Illinois Experiment Ststien.J 



this produces an external injury and at the same 

 time the stalk is often deprived of several unde- 

 veloped leaves. But the tassel should be allowed to 

 develop far enough so that it can be separated 

 alone at the top joint by a careful pull. It is now 

 determined that the detassel- 

 ing of the breeding rows 

 is necessary. This insures 

 cross-pollination and mark- 

 edly increases the yield of 

 succeeding crops. 



Sdection of field rows and 

 seed ears. 



As the crop matures, the 

 corn from each of the de- 

 tasseled breeding rows is 

 harvested. First, all of the 

 ears on the row which appear 

 to be good and which are 

 borne on good plants, in a 

 good position, and with good 

 ear shanks and husks, are 

 harvested, placed in a bag, 

 with the number of the row, 

 and finally weighed, together 

 with the remainder of the 

 crop from the same row. No 

 seed ears should be taken 

 within two or three rods of 

 the inside ends of the rows. 

 The total weight of ear corn 

 which every detasseled row 

 yields should be determined 

 and recorded, for the yield is 

 the primary factor in deter- 

 mining the rows from which 

 all of the ears for the next 

 year's seed selection must be 

 taken. Each lot of ears from 

 each of the detasseled rows, 

 and each single ear of the 

 ninety -six ears ultimately 

 selected for seed, is kept labeled with the num- 

 ber of the row in which it grew, and finally with 

 its own ear number also, and permanent records 

 are made of the number and the description of 

 the ear, the performance record of the row, and 

 the like, so that, as the breeding is continued, an 

 absolute pedigree is established, on the female side, 

 for every ear of corn which may be produced from 

 this seed so long as the records are made and pre- 

 served. It should be the plan to record every fact 

 that bears on the question of efficiency of the 

 plants. We also know absolutely that we have good 

 breeding on the male side, although the exact indi- 

 vidual pedigree of the males cannot be known and 

 recorded. 



Planting for eross-pollination. 



In order to insure cross-breeding to the greatest 

 possible extent, the plan given in Table I should be 

 adopted, varied, perhaps, to meet the necessities of 

 individual cases. The greatest care should be given 

 to the lay-out. 



Fig. 647 

 Showing hereditary 

 power to resist 

 alkali (magnesium 

 carbonate) ; third 

 generation of re- 

 sistant plants com- 

 pared with ordinary- 

 plants growing in 

 the same soil. (Illi- 

 nois Experiment 

 Station.) 



