Graphic analysis of salinity tolerance traits of rice (Oryza sativa L.) using biplot method

Salinity stress is one of the important abiotic stresses affecting rice germination and reduces establishment of seedlings in the field. Six varieties of rice were included in a full diallel mating design and together with their progenies were evaluated for salinity tolerance. General combining ability (GCA) effect was significant for germination percentage reduction (GP) and radicle length reduction (RL); whereas specific combining ability (SCA) were significant for all of traits contain GP, RL, germination rate reduction (GR) and coleoptile length reduction (CL). The negative value of heterosis, due to inverse relation of reduction of traits and salinity tolerance, indicated ideal heterosis. The highest value of negative heterosis for GP, GR, RL and CL were displayed in Shahpasand × Sepidrod, Hassani × Sepidrod, Shahpasand × IRFAON-215 and Sepidrod × IRFAON-215, respectively. The parents with negative GCA are superior for salinity tolerance traits. The Genotype, Genotype-by-Environment (GGE) biplot analysis showed that Sepidrod contributed resistance to GP, GR and IRFAON-215 was the best parent for RL and CL. Respondent this view, Sepidrod and IRFAON-215 can be used either as best parents for selection programs due to their GCA effects, or as a superior parent hybrid programs on their SCA effects