Genetic variability for agronomic and nutritional traits in two white quality protein maize populations

This study was conducted basically to: 1.) estimate the genetic variability for agronomic and grain quality traits among S1 families in two heterotic white maize quality protein maize (QPM) populations and; 2.) investigate the relationship between agronomic and grain quality traits. One hundred Si families were generated from Population 62, a flint white QPM and Population 63, a dent white QPM. They were planted in IPB Experimental Station, UPLB [University of the Philippines Los Baños, College, Laguna, Philippines] site was affected by typhoon. Analysis of quality traits was done, however, in UPLB. Genetic variance component among S1's revealed significant difference for most of the traits studied. Genetic coefficient of variabilityand broad sense heritability were found to be high in almost all the agronomic and quality traits. However, estimates of error variance were greater than their respective genetic variance counterparts for stand count, shelling percentage, ear length, and yield than their genetic variance counterparts in Population 62 and stand count, plant, height, ear length, and ear diameter in Population 63. The bias due to GxE might have been confounded in the error term. Significant genetic variability for amylose, amylopectin and starch content of two QPM Populations was found. This finding is important since they account for the nutritional and taste quality of corn as food. Traits correlation analysis showed higher values for genotypic than phenotypic coefficients. Significant positive phenotypic and genotypic correlations were found between grain yield to plant height, ear height, shelling percentage, ear length, and ear diameter for the two populations. Generally, there was low correlation between agronomic and quality traits. Hence, both traits could be improved simultaneously in these populations: one could be enhance without necessarily impairing the other. There is apparent sufficient genetic variability present in these two maize populations for flowering, agronomic, a yield-related and quality traits. Therefore they are amenable to improvement through recurrent selection-either through intra or inter population improvement. Outstanding S1's were identified for inclusion in the next cycle of improvement of these two populations.