A half diallel cross among eight parents of wheat (Triticumaestivum L.) was evaluated under recommended irrigation and drought stress in RCBD with three replications. The mean performances showed that the parental line P4 had the highest number of spikes per plant and grain yield/plant at drought irrigation treatment. The cross P3 x P6 possessed the highest value at number of spikes per plant, also the cross P2 x P5 had the highest mean value for 1000-kernel weight and grain yield at stress irrigation treatment. As for number of kernels per spike and1000-kernel weight; the parental variety Yacora (P8) gave the greatest value at stress irrigation treatment. For number of kernels per spike, the four crosses P1 x P2, P2 x P5, P4 x (Gemm.9) P6 and (Sahel 1) P7 x (Yacora) P8 gave the most desirable heterotic effects relative to mid-parent and better parent in both irrigation treatments. For 1000- kernel weight, the four crosses P1 x P2, P1 x (Gemm.9) P6, P2 x (Sahel 1) P7 and P3 x (Sahel 1) P7 gave the most desirable heterotic effects for the mid-parent in both irrigation treatments. For grain yield/plant, the three crosses P2 x P5, P3 x (Gemm.9) P6 and (Gemm.9) P6 x (Sahel 1) P7 gave the most desirable heterotic effects relative to mid-parent and better parent in both irrigation treatments. A total of 31 amplicons (amplified fragments) ranging from 96 bp to 401 bp were obtained by ten SSR primers. SSR primers BARC004 and BARC010 exhibited the highest number of fragments (6 and 5 amplicons, respectively). While primers BARC012, BARC072, BARC078 andBARC003revealed the lowest number of fragments (2 amplicons for each). The total number of polymorphic bands was 18; which represents a level of polymorphism around 58%. The SSR primersBARC004 and BARC010 which gave the highest number of polymorphic bands generated unique profiles for most of the wheat genotypes studied. Whereby SSR primer BARC066 was able to identify five genotypes out of the eight, namely L4, L5, Yacora, Sahel1 and Gemmeiza 9.Whereas, SSR primer BARC004 generated 6 profiles for the eight genotypes with six unique profiles for L2, L3, L5, Sahel 1, Yacora and Gemmeiza 9. The lowest genetic similarity was observed (0.67) between Sahel1 and each of L1 and L2. While, the highest genetic similarity was observed (0.96) between L1 and L2. According to correlation analyze between the genetic distances (GD) and each of mean performance and heterosis under control and drought treatment it was noticed that there was a low correlation between most examined pairs of parameters, except the correlation between genetic distance and mid parent heterosis for number of spikes per plant. The results indicated that SSR can be used as a tool for determining fingerprint for each line and extent of genetic diversity among wheat genotypes into different groups but when used a large number of primers. |
