结实期动态温度对软米粳稻产量和品质的影响

Effects of dynamic temperature at grain filling stage on yield and quality of soft japonica rice

以软米粳稻南粳46和苏香粳100为供试材料,通过人工气候室设置梯度温度模拟水稻灌浆结实期温度动态递减变化,设置结实期动态高温、常温和低温3个处理,以室外温度作为对照(CK),研究结实期动态温度对软米粳稻产量及其构成、干物质生产和稻米品质的影响。结果表明,与常温处理相比,结实期低温处理显著降低水稻产量,而高温处理并未减产。结实期温度主要通过影响结实率和千粒重而影响产量,高温处理下千粒重呈减少趋势;低温处理显著降低了结实率,但千粒重显著增加。对物质生产而言,结实期低温处理显著提高茎鞘干物质重及其比例,降低穗部干物质重及其比例,减少总干物质积累量。对稻米品质而言,结实期高温和低温处理均降低精米率和整精米率,导致加工品质变劣;高温处理增加垩白粒率和垩白度,而低温处理减少垩白粒率和垩白度,但品种间变化不一;随着结实期温度升高,稻米蛋白质含量增加,直链淀粉含量降低;高温和低温处理下稻米胶稠度均变短和米饭食味值下降。因此,结实期温度过高或过低都不利于软米粳稻加工和食味品质改善。

Two soft japonica varieties(Nanjing 46 and Suxiangjing 100)were used as materials.Dynamic diminishing temperatures at grain filling stage were set through artificial climate chamber,that is,high temperature(HT),normal temperature(NT),low temperature(LT),and the outdoor temperature(CK).The effects of dynamic temperature at grain filling stage on yield and its composition,dry matter production and rice quality of soft japonica rice were studied.The results showed that compared with NT treatment,LT treatment significantly reduced rice yield,while HT treatment did not reduce rice yield.The grain filled percentage and 1000-grain weight were affected by temperature at grain filling stage,and 1000-grain weight decreased under HT treatment,LT treatment reduced significantly the grain filled percentage,but increased significantly in 1000-grain weight.For dry matter production,LT treatment increased significantly dry matter weight and its proportion in stem and sheath,decreased dry matter weight and its proportion in panicle,and decreased total dry matter accumulation.For rice quality,both HT and LT treatments reduced milled rice rate and head rice rate,resulting in inferior processing quality.HT treatment increased the chalkiness grain percentage and chalkiness degree,while LT treatment decreased the chalkiness grain percentage and chalkiness degree,but the change was different between two varieties.Protein content increased and amylose content decreased with increasing temperature at grain filling stage.Under both high and low temperature treatments,gel consistency became shorter and rice taste value decreased.Therefore,too high or too low temperature at grain filling stage was not conducive to the improvement of processing and eating quality in soft japonica rice.