Evaluation of drought tolerance in dry lands wheat genotypes under different moisture conditions

In order to study of drought tolerance in bread wheat genotypes, this study was conducted in Maragheh dryland agricultural research station. The study included two experiments and the statistical design of each experiment was a RCBD with four replications, and 20 bread wheat genotypes that were compared under drought stress (rainfed) and supplementary irrigation. Analysis of simple variance supplemental irrigation showed that there were significant differences among lines in grain yield, biological yield, harvest index, spike number in square meter, number of grain per spike and thousand kernel weight. Also, in drought stress experiment, there were significant differences among wheat genotypes in agronomic traits such as harvest index, spike number in square meter, grain number per spike and thousand kernel weight, but there were non-significant differences in grain yield and biological yield. Combined analysis of variance or two experiments showed that, drought stress significantly reduced harvest index, grain respect to number per spike and thousand kernel weights but it had non-significant effect on grain and biological yield. Under drought condition lines No. 3 (ARG/R16// BEZ* 2/3/AGRI/KSK/5/TRK13/6/M) and11(M-70-4/5/ Alborz/ 4/ K6290914/ Cno// K58/ Tob/3/Wa) had the highest grain yield by an average of 2.2 and 2.19 t.ha^-1 respectively, and under supplemental irrigation experiment, lines No.3 and 17 (DARI98-MA-39CIT98/99(F4)-1MA-0MA) produced the highest grain yield with an average of 3.84 and 4.19 t/ha grain yield. Results indicated that genotypes No. 3 and 17 had the highest amounts of GMP, MP and STI, therefore were selected as the most tolerant lines. Finally, under supplementary irrigation, genotypes No. 3 and 17 and in rainfed condition No. 3 and 11 could be recommended.