Uncovering Genetic Variation and Co-Located QTL for Seed Germination under Salt and High Temperature Conditions in Recombinant Inbred Lines of Tomato

Abiotic stresses such as salt stress, high temperature and others can affect seed germination, germination speed, seedling growth in the field and final yield. But genetic variation exists among tomato germplasm response to adverse maternal environments. One hundred one Recombinant Inbred Lines (RILs) tomato along two parents were replicated twice to teste seed germination and detect QTLs under salt stress, high temperature and control conditions. Strong significant (P<0.001) difference observed among RILs for all germination parameters under three growth conditions, indicating that high genetic variation observed for seed germination. Germination was more delayed at -0.5 MPa of NaCl, salt stress than high temperature and control. Recombinant Inbred Line of 291 showed the highest germination rate and better performed for all germination traits under salt stress, high temperature and control conditions. QTL analyzed showed at least 1 to 4 significant QTLs per trait identified. Furthermore, four significant co-located QTLs were found on chromosomes 9 and 11, each of two controlling for early set and speed of germination traits, each ranging from 9.9 % to 13.2 % per traits under salt and high temperature stress conditions. This might be suggesting that the common base of genes control for multiple traits. The study demonstrated that some derived RILs showed resilience to germinate under abiotic stresses conditions. Further study is required on co-located QTL through fine mapping, validation and will provide valuable insights into the genetics base of seed tomato for germination under salt stress and high temperature conditions.