Simple correlations among 13 characteristics of 53 maize single cross hybrids, grown in a performance trial planted April 20 and harvested October 10, 1979, are estimated (Table 1).
The kernel moisture content at harvest correlates highly significant negatively to the amount of active temperature for maize (over 10o C and below 30o C) between the date of "black layer" formation and the date of harvest (r = -0.72***), to the kernel percentage in the ear (shelling percent) (r = -0.60***), and highly significant positively to the ear length (r = 0.61***). Lower but significant positive correlations are observed between kernel moisture at harvest and ear height (r = 0.48**), pericarp thickness (r = 0.43**), grain yield per hectare (r = 0.43**), kernel size (r = 0.38**), and ear diameter (r = 0.37**). The length of ear shank, the ear husk number, and the kernel row number do not correlate significantly to the kernel moisture content in this experiment.
Large difference in kernel moisture content among hybrids of the same maturity (black layer formation stage) is observed (Fig. 1), due to the differences in kernel size, shelling percent, pericarp thickness and other characteristics. Hybrids of the same yield per hectare differ in kernel moisture content at harvest (Fig. 2) because of the differences in characteristics related to the kernel drying rate.
The low moisture content at harvest of some hybrids is due to the early physiological maturity (black layer formation) date, short ear, small ear diameter, while the low moisture content in other hybrids, more productive and later in "black layer" formation date, is due to the thinner pericarp, larger kernel row number, smaller kernel size, and smaller husk number.
The relationships among the characteristics studied show the possibility for improvement of drying rate in maize by breeding work without reduction of yield.
Figures 1 and 2.
Trifon M. Georgiev and Illia Iv. Mouhtanov
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