Vigor effects of visible recessive alleles in hybrids

Since a number of the visible recessive alleles (point mutants) appear to affect vigor characteristics as heterozygotes in the inbred line a study is in progress to study the vigor characteristics associated with these alleles as heterozygotes in hybrid combination. At this time the data have been analyzed for one such allele in hybrid combination. The allele involved is case 14, ora3 (orange endosperm). The control hybrid is Oh43 x Oh551 which is compared with Oh43-ora3 x Oh551. The results are presented below:
 
+/+ +/-
Days to silk 78.69 77.71**
Plant height (cm) 235.94 244.84**
Grain wt. per 100K (gm) 36.06 38.61**
Grain wt. per plant (gm) 229.68 221.83*
Ear length (cm) 18.25 17.80**
Ear diameter (cm) 4.83 4.76**
Kernel row no. 15.23 14.81*
Ears per plant 1.30 1.28

*, ** significant at P = 0.05 and 0.01 levels, respectively.

Thus, this allele as a heterozygote in hybrid combination decreases the time to silking, increases plant height, increases kernel weight and decreases yield expressed as grain weight per plant due to smaller ears. The number of kernels of the heterozygote must be less. The data have not been analyzed on the vigor effects of this allele in the inbred line, however observation indicates that the heterozygous plants are taller than those of the normal inbred line plants.

E. J. Dollinger


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