Variability and interrelationships between traits of two maize populations

Abstract

Synthetic maize populations are used in breeding as a source of superior inbred lines to be used as parental components of hybrids. Estimates of genetic variability, broad-sense heritability, and genetic and phenotypic correlations for grain yield, delayed silking, percentage of barren plants, grain moisture content and number of ears per plant were studied in two broad-base synthetic maize (Zea mays L.) populations, NS796a/92 and NS2040b/92. The nested design (random model) method was applied to assess the performances of half-sib families under conditions of severe drought during the 1994 and 1995 growing seasons in two locations. No significant differences were found between the populations for grain yield, delayed silking and number of ears per plant, but population NS796a/92 had a significantly lower percentage of barren plants and grain moisture content than population NS2040b/92. Broad-sense heritability estimates were relatively high for grain yield (51.4% and 58.9%), percentage of barren plants (52.4% and 54.1%), delayed silking (47.1% and 37.3%), grain moisture (60.4% and 60.8%) and number of ears per plant (58.9% and 66.7%). a highly significant positive genetic correlation was found between grain yield and grain moisture in population ns796a/92 (rg=0.77**) and between grain yield and number of ears per plant in population NS2040b/92 (rg=0.99**). Grain yield was negatively correlated with the percentage of barren plants and delayed silking in both populations.