Genetic study of some drought tolerance indicators in the first generation of durum wheat (Triticum durum Desf.)

Because of the lack of rainfall in arid and semi-arid areas in the Kurdistan Region, it’s required wheat genotypes suitable for these conditions. In; 2020-2021 ten wheat genotypes were crossed. In; 2021-2022 Grains of F1s and the parents were planted under rain-fed and supplementary irrigation in Koya Agriculture Research Station (Erbil) to study the genetic properties by Griffing and Jinks-Hayman method for some drought tolerance indices such as stress susceptibility index SSI; geometric mean productivity GMP; mean productivity MP; tolerance Index TOL; and yield stability index YSI; through the grain yield under stressed (Ys) and yield potential (Yp) conditions. Significant; differences were found among parents and F1s for all indices. Results; of genetic analysis imply to high general combining ability GCA; of some parents for different indices. Some crosses had specific combining ability SCA; for most of the indices. The dominant; component (H1) was higher than the additive (D̂) and average degree of dominance ( ) was greater than one for all indices. Dominant; and recessive alleles in gene locations (H2/4H1) were less than 0.25 for all traits, showing that dominance was not distributed regularly among parents. The number; of dominant to recessive genes ratio (KD/KR) was more than one for Ys, SSI; GMP; and YSI; with values of (1.25, 1.61, 1.09 and 1.62) respectively, indicating the increase of dominant genes in parents for these traits, while it was less than one for Yp, MP and TOL; with values (0.54, 0.90 and 0.78) respectively shows increase of recessive genes in parents for these traits. Heritability; Hns. has ranged from 0.268 for Ys to 0.339 for Yp. Parents 1 and 3 were the best for GCA; and most of the traits. Crosses 1×7 and 1×8 had the best performance for most of the traits, and 4×9 was the best for SCA.