GENETICS OF ENDOSPERM PROTEINS AND AGRONOMIC TRAITS IN MAIZE (Zea mays L.)

GENETICS OF ENDOSPERM PROTEINS AND AGRONOMIC TRAITS IN MAIZE (Zea mays L.)

Abstract:

The study examined genetics of endosperm proteins and agronomic traits in maize genotypes. Maize genotypes of varying levels of endosperm protein fractions were grouped into four female and two male parents and mated using North Carolina mating design II in 2011. The resultant 8 F1 hybrids and six parents were evaluated in 2011/2012, using Randomized Complete Block Design, replicated three times during two seasons: wet and dry seasons at Samaru. Protein quality assessment was carried out using Bradford protein assay method. Ten agronomic traits and protein quality of parents and F1’s were studied to determine their heterotic response and genetic analysis (general combining ability (GCA), specific combining abilities (SCA) and heritability) of the maize genotypes. From the analysis of variance, significant differences were observed among the genotypes for the following agronomic traits: days to 50% seedling emergence, days to 50% flowering, days to 50% silking, plant height, ear height, number of cobs per plant, number of kernel rows, ear length, ear weight, grain yield and for protein quality traits (albumins/globulins, zeins, glutelins). Sammaz 20 was the best parent, having better GCA values in terms of grain yield and other agronomic traits during the wet and dry seasons, Sammaz 17 was the best parent, having better GCA values for grain yield and most traits for the two seasons and Sammaz 37 was the best parent with better GCA values for protein quality. The crosses with better SCA values in terms of grain yield and most agronomic traits for the wet season was Sammaz 20 x Sammaz 14 and Sammaz 17 x Oba 98 for the dry season. Sammaz 20 x Sammaz 14 was the best cross with better SCA values in terms of grain yield and most agronomic traits for the two seasons, while Sammaz 18 x Sammaz 14 was the best combiner for protein quality. Narrow sense heritability (h2ns) estimates ranged from 0.21 for days to 50% seedling emergence to 0.80 for ear length in the wet season, 0.55 for days to 50% flowering and days to 50% silking to 0.96 for ear weight in the dry season and 0.11 for number of kernel rows to 0.99 for ear weight. Protein quality traits had negative heritability estimates, for albumins/globulins but positive for glutelins 0.51. The σ2 GCA/σ2 SCA variance ratios for most of the agronomic traits in the wet season and dry season were predominantly governed by non – additive gene action, while across season was governed by additive gene action. The σ2GCA/σ2 SCA variance ratios for protein quality traits were all governed by non-additive gene action. High percentage heterotic response was observed for both agronomic and quality traits. Sammaz 20 x Sammaz 14, Sammaz 37 x Sammaz 14 and Sammaz 17 x Sammaz 14 had the highest heterotic response for agronomic traits (days to 50% seedling emergence, days to 50% flowering, days to 50% silking, plant height, ear height and grain yield) while Sammaz 37 x Oba 98, Sammaz 18 x Oba98 and Sammaz 20 x Oba 98 had the highest heterotic response for quality traits (albumins/globulins and glutelins).

GENETICS OF ENDOSPERM PROTEINS AND AGRONOMIC TRAITS IN MAIZE (Zea mays L.)

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