Effect of fractionisation on the seed vigor and yield elements of some Mv maize hybrids

The seed of seven maize hybrids was graded according to seed size and the fractions thus obtained were analysed with respect to the biological value of the seed and for yield components. Measurements were made on the germination ability, cold tolerance and early vigour of the seeds, after which the yield, yield components and reduction in grain moisture content were studied under field conditions. The various fractions were found to have different values of cold tolerance and adaptability to suboptimum environmental conditions. Flat fractions were significantly superior in the hybrids Norma, M nu 1444, M nu 1454, M nu 1486 (KL) and M nu 1488. In the case of M nu 1355 and M nu 1484 there was no convincing difference in biological value between the fractions. As to the question of whether there is any difference in yield potential between the fractions, the findings were as follows: in four of the hybrids examined (Norma, M nu 1355, M nu 1444, M nu 1454) the yields of the large flat (NL) fraction fulfilled expectations. In two hybrids (M nu 1486, M nu 1488) the small flat (KL) fraction gave the best results, while in the case of M nu 1484 fractionisation did not lead to any yield diffence. Although significant differences in yield were only found for Norma and M nu 1486, the smaller differences found in the other cases should not be ignored. The worst results, as regards both yield and the biological value of the seed, were obtained not for the large, bur for the small round (KG) fraction. In the case of the large flat fraction, not only the inheritance of the genetic material, but also the physiological and morphological perfection of the seed are more probable. Fractionisation thus has an effect on the kernel yield, but this differs from one genotype to the other. It is suggested that the study should be extended in the future to include a larger number of hybrids (those in the course of registration).