华南籼稻新品种(组合)生育中后期耐冷性研究

Cold tolerance of the new-bred South China Indica rice cultivars in at different stages of growth and development

2009年早、晚季用PGV–36人工气候箱对华南籼稻新品种"合美占"、"黄丝占"、"粤广丝苗"和三系法杂交稻组合"天优312"、"天优390"于幼穗分化5～6期、始穗期、开花期和灌浆初期进行了低温胁迫研究。结果显示:①幼穗分化5～6期、始穗期和开花期,低温胁迫会导致华南籼稻新品种(组合)植株高度降低,单穗产量及结实率下降。②幼穗分化5～6期低温胁迫会导致水稻穗长缩短,每穗总粒数减少,而其他3个时期的每穗总粒数不会受低温胁迫影响;幼穗分化5～6期低温胁迫会导致穗下第三节间长度极显著缩短,始穗期和开花期低温胁迫则导致穗下第二、第一节间长度缩短;始穗期和开花期低温胁迫会导致稻穗包颈或包颈加剧,幼穗分化5～6期则无此现象发生。③处于不同生育时期的水稻遭遇低温胁迫,其耐冷能力不同,其差异达到极显著水平,耐冷能力大小依次为灌浆初期、开花期、始穗期、幼穗分化5～6期。同一品种(组合)在不同生育时期的耐冷能力不同:天优390在幼穗分化5～6期、灌浆初期耐冷能力最强,但在始穗、开花期较弱;粤广丝苗在始穗期、开花期耐冷能力最强,但在幼穗分化5～6期较弱。

Early and late crops of South-China lndica rice cultivars, Hemeizhan, Huangsizhan and Yueguangsimiao, and three-line hybrid rice combiniations Tianyou312 and Tianyou390 were chosen in Guangzhou in 2009 to study the coldtolerance at the 5-6 phases of panicle differentiation, at initial heading stage, at flowering stage and at initial milking stage in the batanatrons （PGV-36）. The results showed that chilling stress conducted at 5-6 phases of panicledifferentiation, at initial heading stage and flowering stage decreased the plant height, the stem intemodes length, the grain yield per panicle and the seed setting rate of South-China Indica rice cultivars and combinations. The rice cultivarsand combinations responded differently to the chilling stress at different stages of growth and development. At the 5-6 phases of panicle differentiation but not other stages, the panicle length became shorter, and the total spikelets per paniclebecame fewer under chilling stress. The third internode under the panicle was shortened very significantly under chilling stress at the 5-6 phases of panicle differentiation and the first and second internodes became shorter at the initial headingand flowering stage. Incomplete panicle exertion was aggravated at the initial heading and flowering stage but not at the 5-6 phases of panicle differentiation. The cold tolerance of the tested materials was distinctive significantly different atdifferent stages of growth and development, rice cultivars and combinations at initial milking stage showed the highest cold tolerance followed by flowering stage, initial heading stage and 5-6 phases of panicle differentiation. And for thesame cultivar or combination, the cold tolerance was different at different stages, Tianyou390 showed high level of coldtolerance at the 5-6 phases of panicle differentiation stage and initial milking stage, and weak tolerance at the heading and flowering stage; Yueguangsimiao showed low level of cold tolerance at the 5-6 phases of panicle differentiation, andhigh tolerance at the heading and flowering stage.