FULL-SIB vs S-1 SELECTION SCHEME FOR THE IMPROVEMENT OF A MAIZE POPULATION FOR TOLERANCE TO LOW SOIL NITROGEN

摘要

Estimating and comparing quantitative genetic information for different selection procedures would aid the identification of the best method for the improvement of desirable traits in maize populations. In this study, a maize population was subjected to both full-sib and S-1 recurrent selection schemes to determine the better of the two procedures for improving the population for tolerance to low soil nitrogen. For both schemes, estimated genetic variances were generally large enough for effective selection to take place. Except for ears per plant and stay green under low-N, genetic variances due to S-1 were larger than those due to full-sib selection. Also, genotype x environment component of variance due to S-1 selection was larger than those due to full-sib selection except for AS1. Genetic variances under high-N for most traits were also larger for SI than for full-sib, but variances due to genotype x environment interaction under high-N were larger for full-sib selection for ear aspect, AS1 and grain yield. Heritability estimates for all the traits except for root lodging under low-N were moderate to high, but the estimates were higher for S-1 than for full-sib family selection under both selection types. However, considering time, cost and operational efficiency, modified full-sib family selection is considered more efficient to S-1 selection for the improvement of maize for tolerance to low soil nitrogen.