Effect of Water Stress and Spraying of Potassium Iodide on Agronomic Traits and Grain Yield of Bread Wheat (Tiriticum aistivum L.) Genotypes

In order to study the effect of water stress and chemical desiccation (potassium iodide) on grain yield and agronomic traits of 8 wheat genotypes, a field experiment was conducted using a split split plot design based on a randomized complete block design with three replications in Torogh Agricultural and Natural Resources Research Station (Mashhad, Iran) in 2006-2007 and 2007-2008. Main plots were assigned to two levels of water stress treatments; D1: optimum irrigation, and D2: cessation of watering from anthesis to maturity stages. Sub plots were assigned to eight bread wheat genotypes: 9103, 9116, 9203, 9205, 9207, 9212, C-81-10 and Cross Shahi (drought sensitive); and photosynthetic conditions with two levels: P1: using of current photosynthesis and P2: inhibition of current photosynthesis were in sub-sub plots. The results showed that the effects of water stress and photosynthetic conditions on number of total florets per spike (NTF/S), seed set percentage (SSP), spike harvest index (SHI), duration of grain filling (DGF) and grain yield (GY) were significant. There was a significant difference between genotypes for spike dry weight at anthesis (SDWA), number of spikletes per spike (NSP/S), NTF/S, SSP, SHI, spike partitioning coefficient (SPC), plant height (PLH), spike length (SL), DGF and GY. 9103 genotype produced the most GY (7870 kg/ha) under D1P1 treatment. The least GY (1114 kg/ha) related to Cross Shahi cultivar under D2P2 treatment. Considering that C-81-10, 9103 and 9116 genotypes showed the highest grain yield, potential for reserves and remobilizations of assimilates under different irrigation conditions thus, these genotypes could be introduced as promising in breeding programs for arid and semi-arid regions.