the survey of ending season drought stress impact and different planting dates on grain yield and gaining weigh t rate and wheat filling period characteristics in new bread wheat genotypes

in order to study planting date impacts and ending season drought stress  on grain yield and  gaining weight  rate  and wheat filling period characteristics in new advanced bread wheat genotypes ,this research  is done by using plan statistical  of spilt plot  in form of complete random blocks basic  plot with 3 replications in both common separated irrigation  and ending season drought  stress tests (stop irrigating in50% pollination phase )  in research institute field  for breeding and  providing seeds and seedling  in karaj  in 387-1388. planting date factor  is studied  in 2levels mehr 20th and aban10th  in main plots  and 4 genotypes resisting to bread wheat drought stress including c-85-d7;c-85-d8; c-85-d9; c-85d13 with  alvand  check value in minor plots in both  tests. the results of variance analysis for measured characteristics in both common irrigation and drought stress tests show that impacts of planting dates ,genotypes  and planting date interaction  multiplied by genotype on grain yield characteristics ,rate gaining weight and wheat filling period (in both tests) were meaningful at 1% level. according to results of  test average comparisons in both  common irrigation condition and drought stress , showed  that c-85-d9 in both conditions  having most wheat filling speed  and c-85-db having most wheat filling period and meanwhile both genotypes  had rather good grain yield in both conditions . recent results have showed that different wheat genotypes  have interaction with environmental conditions so that each genotype using  its own special strategies for resisting to stress.