ASSESSMENT OF SESAME GENOTYPES AND THEIR 28 (F1) FOR AGRONOMIC CHARACTERS AND STRESS TOLERANCE INDICES UNDER TWO IRRIGATION REGIMES

Drought is one of the biggest obstacles facing the cultivation and production of the sesame crop, especially in areas where there is shortage of water or unequal rain. An investigation was done to assess the effect of deficit irrigation on agro-morphological, yield traits and stress tolerance indices of eight sesame genotypes and their twenty-eight (F1) crosses. The parents selected for a half-diallel crosses were unique and diverse. The experiment was conducted during the summer season, 2017 and 2018 at Field Crops Research Institute, ARC, Giza, Egypt. Deficit irrigation was induced by preventing two irrigations, at initial of flowering and before maturity; while normal irrigation applied as recommended. Nine stress tolerance indices were deeply estimated as selection criteria for identification of drought tolerant genotypes under moderate level of drought stress (Stress Intensity SI=0.25). Data revealed that irrigation regimes affected all studied traits significantly. Genotypes and interaction between irrigation regimes x genotypes were highly significant for all morphological, yield and seed chemical composition traits. Among the parents, P5(N.A.604), P6(Shandweel 3) and P4(Um Shagera) and the crosses, G16(P2XP3), G35(P6XP8), G27(P4XP5), G36(P7XP8), G10(P1XP3) and G26(P3XP8) were obtained the highest seed yield. According to drought tolerance indices rank average, the parents, P4(Um Shagera), P7(B21-3) and P5(N.A.604); and the F1, G22(P3XP4), G16(P2XP3), G34(P6XP7), G23(P3XP5), G35(P6XP8) and G36(P7XP8) were the most drought tolerant genotypes performed will under both stress and non-stress conditions, with minimum reduction in seed yield under stress condition. In addition, the parents P4(Um Shagera), P7(B21-3), and P1(N.A.373); and the F1 G28(P4XP6), G34(P6XP7), G22(P3XP4), G23(P3XP5), G14(P1XP7) and G25(P3XP7) scored the highest yield stability index and relative stress index. So, the drought tolerant parents were recommended for further breeding program; also, selection should be focused on F1 progenies that performed well under both stress and non-stress conditions in the coming segregating generations to select drought tolerant lines.