Abstract
A total of fourty two maize hybrids produced through a full diallel mating design and seven parental inbred lines were evaluated in three sites located at different agro-ecological zones in Kenya to determine the genetic parameters governing the inheritance of grain yield and related agronomical traits. The genetic parameters studied among the traits included the mean performance, genotypic variances, phenotypic variances, genotype by environment variances, broad sense heritability and phenotypic and genotypic correlation coefficients. Significant differences were recorded for all traits studied thereby revealing the diversity of the maize genotypes. The grain yield and days to maturity which showed high heritability had low genotypic variances suggesting the involvement of non-additive gene action which could be utilized through heterosis breeding. Ear height and plant height showed the highest heritability and high genotypic variances suggesting the preponderance of additive gene action. Grain yield was positively and strongly correlated with ear height and plant height. The tall plants with high ear placement gave better yields and this could be attributed to the high dry matter accumulation function carried out by the high number of leaves possessed. The positive relationships observed in this study imply that the desirable traits in these hybrids could be exploited in further breeding activities for the development of composites and synthetics for the resource constrained maize farmers who cannot access hybrid seeds every year.
Highlights
Maize is the third most important food crop of the world, after wheat and rice, providing 15% of the protein, and 19% of the calories for the developing countries (Shakoor et al, 2007)
A total of fourty two maize hybrids produced through a full diallel mating design and seven parental inbred lines were evaluated in three sites located at different agro-ecological zones in Kenya to determine the genetic parameters governing the inheritance of grain yield and related agronomical traits
The SCA by environment was significantly different for grain yield, plant and ear height, diseased ears and root lodging
Summary
Maize is the third most important food crop of the world, after wheat and rice, providing 15% of the protein, and 19% of the calories for the developing countries (Shakoor et al, 2007). The yield has a multiplicative effect on the end product of many factors otherwise referred to as yield components (Zeeshan et al, 2013) These yield components are inherited with minimal environmental deviations, and selection based on them is more appropriate as opposed to the yield per se (Nagabhushan et al, 2011). The assessment of performance of parental lines based on the yield components could aid in the selection of superior parents for the production of better yielding hybrids (Bocanski et al, 2009). This can successfully be achieved if the genetic parameters which govern inheritance of important agronomic traits are established (Mahiboobsa et al, 2012). The proper characterization of the physiological traits and their relationships with maize yield and yield components coupled with utilization of the revealed genetic variability could lead to improvement and broadening of the diversity of the maize gene pool (Alake et al, 2008; Al-Tabbal et al, 2012)
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