干旱胁迫对不同穗型超级稻品种产量及穗部性状的影响

The effect of drought stress on yield and panicle traits of different type super rice varieties during panicle initiation to grain filling stage

通过水分仪结合称重法的盆栽试验,在水稻幼穗分化至灌浆结实的不同时段,人为控制土壤水分以模拟干旱胁迫的发生,研究了中度干旱胁迫对不同穗型超级稻品种产量因素及穗部性状的影响。结果表明：不同时段的中度干旱胁迫对水稻产量及穗部性状都有影响,最终籽粒产量均比正常供水时显著下降,穗分化15-30 d控水处理影响最大,其次是开花至花后15 d和花后15-30 d的控水处理,减产原因主要是结实率下降和千粒重降低。不同品种受影响的程度有所不同,超级稻品种较普通杂交稻品种来说相对要小,但也有受影响较大的超级稻品种,大穗型品种（国稻6号、两优培九、Ⅱ优7号）受干旱胁迫的影响程度要低于中穗型品种（天优998、Ⅱ优602、汕优63）。

With experiment cultivated in pots and contrived simulation of drought stress, method to determine soil moisture by electronic balance （made in Shanghai） and W.E.T Sensor（ML2x type, made in USA）, the effect of drought stress on panicle traits and yield components of different panicle type rice varieties （more or middle grains per panicle） was studied. The results showed that middle level drought stress of different stage from panicle initiation to grain filling had various degree of influence on rice panicle characteristics, yield and its components, and caused the reduction of grain yields （more than 20% of each variety）. Water treatment from 15 to 30 days after panicle initiation had the greatest influence, followed by 0 - 15 d and 15 - 30 d after flowering, however, 0 - 15 d after panicle initiation had the least influence. Compared with normal water supply, drought stress during panicle growth and development stage led to panicle length decrease obviously and numbers of the secondary branches and total spikelets per panicle reduce significantly, and drought stress during grain filling led to great reduction of filled grain numbers, fertility rate and 1000-grain weight, which caused the reduction of grain yields. The affecting degree of drought stress on panicle traits and yield components varied from these varieties because of different sensitivity to water stress, and the influence on super rice varieties was less compared with common hybrid rice variety （Shanyou 63） in general The rice varieties with more grains per panicle （eg. Guodao 6, Liangyoupeijiu and Ⅱ you 7） showed lower degree influence of drought stress on yield components and panicle traits than those with middle grains per panicle （eg. Tianyou 998, Ⅱ you 602 and Shanyou 63）.