Genetic analysis for grain flling duration in wheat using joint segregation analysis

Abstract

Mixed inheritance analysis using joint segregation analysis was investigated in 6 basic populations (P1 , F 1, P2, BC1, BC2, andF 2) of 4 wheat crosses, i.e. Hashim-08 × LU-26, Farid-06 × Shafaq, Parula × Blue Silver, and TD-1 × D-97603, for grain flling durationduring the crop season of 2011/2012. In cross Hashim-08 × LU-26, the duration of grain flling was controlled by 1 major gene and theadditive-dominance-epistasis of polygenes (model D). In cross Farid-06 × Shafaq, the duration was controlled by additive-dominance-epistasis of 2 major genes (model B-1). However, in crosses Parula × Blue Silver and TD-1 × D-97603, the period of grain flling wasunder the control of 2 mixed groups of genes including additive-dominant-epistatic major genes plus the additive-dominant-epistasisof polygenes (model E and model E-1, respectively). In cross Hashim-08 × LU-26, the variation and heritability of the polygenes weregreater than those of the major gene, whereas these components were low in cross Parula × Blue Silver. In crosses Farid-06 × Shafaq andTD-1 × D-97603, no polygenes were involved and the duration of grain flling was mainly under the infuence of major genes. For theduration of grain flling, the maximum environmental variation revealed the infuence of environment. Results suggested that due to itsmaximum heritability, early selection would be feasible in cross Hashim-08 × LU-26, while due to low heritability and variation in crossParula × Blue Silver, delayed selection will be efective. Yield improvement based on duration of grain flling could be done throughselection in later generations until the accumulation of the maximum favorable additive genes is achieved.