Improvement for Tolerance to Low Soil Nitrogen in A Quality Protein Maize (QPM) Variety: Variability and Selection Gains

Abstract

A set of 250 S1 lines of a quality protein maize (QPM), ART/98/ILE 1-OB, were evaluated along with six checks under low soil N in Mokwa and Zaria in 2016 to determine the level of genetic variability in the QPM population with the aim of improving it for tolerance to low soil N. Data were collected on days to flowering, Anthesis-Silking Interval (ASI), plant height, stay green ability, plant aspect, number of ears per plant and grain yield under low and high N. Analysis of variance was conducted from which genetic variances were estimated. Heritability and selection gains were also estimated. Mean square of entry was significant for all the traits studied under low N except for days to silking and ASI. Genetic variance estimates ranged from low to moderate but significantly different from zero for most of the traits studied. Estimates of environmental variance were higher than genetic variance for most of the traits except plant height and grain yield. Heritability estimate was moderate for most of the traits studied. It was however highest for grain yield under low N (49.7%). Gain/cycle was also moderate to high for most of the traits. Stay green ability would improve with selection by 6.07% of the mean. ASI would reduce by -3%, while grain yield would increase by 71% of the mean yield. Appreciable genetic variability exists in the QPM population for tolerance to low soil N and hence, selection will be effective.