CELL MEMBRANE THERMO-STABILITY STUDIES THROUGH JOINT SEGREGATION ANALYSIS IN VARIOUS WHEAT POPULATIONS

Using joint segregation analysis (JSA) technique as statistical approach, mixed inheritance analysis for cell plasma membrane as membrane thermal stability (MTS) was assayed in two parental lines (P-1, P-2) and their four populations (F-1, BC1, BC2, F-2) of four wheat crosses, viz., Hashim-08 x LU-26, Farid-06 x Shafaq, Parula x Blue Silver and TD-1 x D-97603 at Faculty of Agriculture, Gomal University, Dera Ismail Khan, Pakistan during crop season 2011-12. Results revealed that MTS was under control of two mixed groups of genes i.e., additive-dominant-epistatic major genes plus additive dominant-epistasis of polygenes (model E) in Hashim-08 x LU-26 and Farid-06 x Shafaq crosses, respectively. In cross Panda x Blue Silver, it was governed by mixed genes i.e. one major-gene and additive-dominance-epistatic polygenes (model D). However, in cross TD-1 x D-97603, the MTS was under the influence of mixed epistasis of two major genes plus polygenes (model E-1). Polygene variation and polygene heritability were higher than major gene variation and heritability in crosses Hashim-08 x LU-26 and Farid-06 x Shafaq. In crosses Panda x Blue Silver and TD-1 x D-97603, the major gene variation and heritability were higher than polygene variation and heritability, indicating maximum contribution of the major genes. While in cross TD-1 x D-97603, epistatic components were also positive and due to which the polygene heritability was almost zero. Moderate to high environmental variation in the MTS for segregating generations revealed that the said trait was highly persuaded by the environment. However, the genetic behavior of the MTS suggested that early selection for MTS in the crosses Hashim-08 x LU-26 and Farid-06 x Shafaq would be efficient. Whereas, the delayed selection in crosses Parula x Blue Silver and TD-1 x D-97603 until the accumulation of maximum favorable genes will be effective.