Effect of irrigation cut at different stages of growth on yield, yield components and grain quality of different cultivars of sorghum seeds

In order to investigate the effect of water deficit tension on different growth stages on yield, yield components and produced grain quality of sorghum seeds cultivars,  an experiments was performed as split plots based on randomized complete blocks design with four replications in Isfahan Ghiam Cultivation and Cattle Farm Company in 2017. The main factor including irrigation cut at four levels (irrigation cut from the pollination stage onwards, irrigation cut from the milking stage onwards, irrigation cut from the paste stage onwards and normal irrigation (control)) and sub-factor including three cultivars of seed sorghum (Sepideh, Kimia and Payam). The results showed that plant height traits, panicle length, one-thousand grain weight, panicle weight, grain weight in panicle, grain yield, protein percentage, sugar, starch and seed fat were affected by irrigation cut at different stages of growth. There was also a significant difference between different cultivars based on height traits, number of claws per plant and length of panicle. The results of the mean comparison showed that water deficit tension reduced grain yield and in terms of water cut-off tension before pollination compared to control caused 63.95 percent of yield loss and in terms of irrigation cut in milking stage compared to control, 34.4 percent of yield loss. While by cutting off the water in the paste stage, the yield increased by 2.2 percent compared to the control. In general, the highest grain yield, one thousand grain weight and panicle weight were obtained in Kimia cultivar, which could represent a more tolerant cultivar to water deficit tension.