Abstract

The objectives of the present study are to determine the performance of six promising durum wheat genotypes for yield stability under heat stress conditions and to compare the application and utility of SRAP (Sequence-Related Amplified Polymorphism) and TRAP (Target Region Amplified Polymorphism ) marker techniques, for analysis of genetic diversity among durum wheat genotypes under heat stress. Field experiments were conducted for four sowing dates, over two seasons, to expose genotypes to different levels of heat stress during the grain-filling period. Grain yield and yield attributes during the grain filling period were investigated. Results indicated that significant variations were observed among different durum wheat genotypes in respect of all yield attributes. The effect of sowing date on the relative grain yield of durum genotypes was of greater magnitude than the effect of year. On the other hand, under the fourth sowing date (20^th January), where heat stress was imposed, line KSUDW104 was the best performing line (3.26 ton/ha) out yielding Benysowef (2.21 ton/ha) by 47.5% and Kronos (2.41 ton/ha) by 35.3%. This line should be recognized as heat tolerant germplasm. The regression coefficients were significant for the six durum genotypes which indicated that they were highly responsive to the change in the average productivity of the growing season. SRAP and TRAP markers, were assayed to determine the genetic diversity of 6 durum wheat genotypes. In SRAP analysis, 45 out of 128 bands (35.16%) were polymorphic while in TRAP analysis, 22 out of 55 bands (40.0%) were polymorphic. The dendrogram based on SRAP markers differed from that based on TRAP markers.

Key words: Durum wheat, genetic diversity, heat tolerance, SRAP markers,TRAP markers, yield stability.