Effects of water stress on the texture of cooked rice and the grain quality of transgenic rice plants carrying antisense Wx gene during grain filling

It is well known that environments have significant effects on the yield and rice quality.In previous study,the indices of quality,such as chalkiness,gel consistency and RVA profile were altered by soil water moisture.Amylose content is always used to evaluate the rice eating and cooking quality.And now the characteristics of RVA profile are preferred for the prediction of the texture of cooked rice.Our earlier work showed that RVA profile of rice flour was affected by water stress,but there was no obvious difference in amylose content between well water and water stress.The objective of the study was to research the effects of water stress on the texture of cooked rice and grain quality for rice with the same genetic background.Three transgenic rice lines CA1,CA2,CA3 carrying antisense Wx gene and wild type(cultivar Wuyunjing 7) were grown in pots and were subjected to water stress from flowering stage to filling stage.The results showed that the grain qualities of transgenic rice plants and Wuyunjing 7 were affected by water stress at the grain-filling stage,head milled rice and the percentage of chalky grains increased obviously(Table 3).Changes of RVA profile of rice flour were noticed,breakdown was lower under water stress than under well water,and final viscosity and setback under water stress were higher than those under well water(Table 4).Effect of water stress on the texture of cooked rice presented on the hardness and adhesiveness,the former was increased and the latter was reduced(Table 5),and there was a tendency of low eating and cooking quality.