GENETICS OF ENDOSPERM PROTEINS AND AGRONOMIC TRAITS IN MAIZE (Zea mays L.)
GENETICS OF ENDOSPERM PROTEINS AND AGRONOMIC TRAITS IN MAIZE (Zea mays L.)
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Date
2013-04
Authors
REKIYA, OTUCHU ABDULMALIK
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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).
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF
A
MASTER DEGREE IN PLANT BREEDING
DEPARTMENT OF PLANT SCIENCE,
FACULTY OF AGRICULTURE,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
APRIL, 2013
Keywords
GENETICS, ENDOSPERM PROTEINS, AGRONOMIC, TRAITS IN MAIZE, (Zea mays L.)