Genetic characterization and molecular mapping of ear height on the basis of generation mean analysis and bulked segregant analysis in maize (Zea mays)

Abstract

The genetic studies of ear height and its related traits were carried out by making crosses between two contrasting parents for ear height i.e, AKON40A (high ear placement) and LM23 (low ear placement) to generate F1 hybrids, which were selfed to produce F2 population and backcrossed with both parents to generate BC1.1 and BC1.2 generations. Generation mean analysis was performed on all six generations for a total of 12 morphological and phenological traits. The genetic components revealed the presence of additive gene action, additive × additive and additive × dominance gene interaction for ear height and plant height. Out of 284 SSR primer pairs, 146 primer pairs confirmed parental polymorphism, while nine primers were exhibited polymorphic in bulked segregant analysis (BSA). These nine primers were used for constructing linkage map in F2 population. Three linkage groups were formed in which LG1 spanned 26.9 cM on chromosome 3 while, LG2 and LG3 spanned 42.1 and 6.7 cM on chromosome 6 and 7, respectively. Gene governing the trait ear height was mapped on chromosome 6 between the SSR primers umc1979 and umc2317 having LOD value of ~ 3 and the phenotypic variance (R2) of 8.5. The prevalence of additive gene action for ear height suggested that recurrent selection can be utilized to improve source population for reducing ear placement by accumulating favourable alleles. Improved source population then can be utilized for inbred line development leading to maize hybrids having medium to low ear placement.