Effects of Drought Stress on Growth and Yield of Rice (Oryza sativa L.) Cultivars and Accumulation of Proline and Soluble Sugars in Sheath and Blades of Their Different Ages Leaves

Abstract

One of the main problems of rice cultivation and production is the lack of water resources, especially during periods of low rainfall which affect the vegetative growth rate and the amount of yield. In this study the effect of low water supply on the number of heading per hill, number of grain per hill, dry weight of vegetative tissues and panicle and 1000 grain weight in three new cultivars of rice including 216, 829 and Zayandeh-Rood were measured under submerged and non-submerged conditions in a randomize complete block design with three replicates. Simultaneously, the variation in proline and total sugars in sheaths and blades of leaves at different ages was determined. The data indicated that Zayandeh-Rood cultivar showed the lowest reduction in shoot dry weigh and the number of tillers per hill under non-submerged conditions. Furthermore, the panicle weight and the number of filled grains per spike were higher in Zayandeh-Rood cultivar than the other cultivars. In addition, the result of this study show that Zayandeh-Rood cultivar in which originated from local cultivars, have higher ability in solute accumulation such as proline and total carbohydrates than the other new lines. Due to correlation between drought tolerance of Zayandeh-Rood and solute accumulation, it may be suggested that the solute accumulation is one of the mechanisms for drought tolerance in rice.