Wheat Triticum aestivum L. Seed Priming For Drought Tolerance

Abstract

Two experiments were conducted the first one at the laboratories of seed testing and certificating directorate /Ministry of Agriculture during 2013. The second one at the Field Crops department / College of Agriculture - University of Baghdad during 2013 to 2014 growing season . The objective was to investigate the effect of seed priming wheat before sowing on the wheat plants tolerance to the drought compared with the non- priming seeds and its relationship with the growth and grain yield. Complete randomized design (CRD) was used for the lab. experiment with four replicate. The aim of lab.experiment was to determine the best concentration of seed priming agents and the most responsive varirty to be applied in the field experiment . In the field experiment , R.B.C.D design used in the arrangement of split- plot with three replicates. The drought treatment (50,70,and 90%) depletion of available water of field capacity occupied the main plots. While seed priming treatments (gibberellins ,Kinetin, cycocel, salicylic acid , kcl, Ascorbic acid ,distilled water and dry seeds). The result of the Lab.experiment revealed that the first concentration of Ascorbic acid and Salicylic acid, the second concentration of Gibberellin, Cycocel and Kinetin and the third concentration of KCL were the best. For the varieties, Bohooth22 was the most responsive one in giving the highest average of germination speed(80.77%),plumule length (12.128 cm) and seedling vigour (19.20) compared with IPA 99 which gave the lowest average of these characters. The results of field experiment , revealed that there were not significant differences between depletion levels (50 and 70%) in the chlorophyll content (46.8 and 48.10 mg.g-1), no. of grain.spike-1 (46.8 and 44.94), 1000 grain weight (39.95 and 40.25 g),grain yield (4.77 and 5.31 t. ha-1)and the biological yield (13.05 and 13.17 t. ha-1) which indicates the possibility of saving 40% of water . Also, in the 70% depletion level gave the highest value of water use efficiency for grain yield (1.124 kg.m-3). The seed priming treatments significantly affected most studied characters . Seed priming with KCL, Cycocel and Gibberellin increased tiller no.(488, 498 and 469), spike no.(453.3 ,460 and 444.1spike . m-2), no.of grain.spiPkel-1(46.12, 45.98 and 49.52)and grain yield(50.098, 5.424 and 5.433 t. ha-1), respectively. Seed priming with cycocel and gibberellins gave the highest value of water use efficiency. The interaction between depletion leves and seed