低温寡日照条件下不同类型杂交稻品种的生态适应性

Ecological adaptability of rice cultivars with different types under the low temperature and weak sunshine condition

探讨杂交水稻品种的生态适应性,为超高产杂交水稻品种合理选用提供依据。在低温寡日照生态区,以生态适应型品种(筑优606和黔优108)及生态敏感型品种(Y两优2号和Y两优302)为试验材料,比较研究了2种类型水稻品种的产量形成、氮素吸收与利用、根系特性的差异。结果表明:与生态适应型品种相比,生态敏感型品种的产量平均降低了13.8%,其中结实率和千粒质量分别降低了9.9%和15.5%;较生态适应型品种,生态敏感型品种在分蘖中期、抽穗期和成熟期的氮素积累量分别降低18.8%、10.8%和14.5%,氮肥吸收利用率降低了17.9%,生态敏感型品种在抽穗期的茎叶含氮量呈降低趋势,成熟期的茎叶含氮量及比例均呈增加趋势,氮素转运量和氮素转运率分别降低了24.6%和19.4%;生态敏感型水稻品种在抽穗抽穗期和成熟期根系伤流强度分别降低了8.8%和21.6%。籽粒库容充实差是低温寡日照地区杂交水稻品种适应性的主要产量特征,而生育中后期氮素营养积累少、转运率不高是影响产量的重要生理原因。

Besides the genetic cultivar characteristic and cultivation strategy, the environmental condition is considered as another important factor affecting the grain yield in rice. Previous studies were carried out on yield formation of rice under the low temperature and weak sunshine condition, however, the ecological adaptability such as yield formation, nitrogen accumulation and utilization of different thermos-photoperiod sensitive rice cultivars to the low temperature and weak sunshine is still obscure, as well as the response mechanism. The main objective of this study was to determine the ecological adaptability of different rice cultivars under the low temperature and weak sunshine condition in the middle and late growth duration. Field experiments were conducted in 2013 and 2014 in Guiyang, where was regarded as a representative eco-site with low temperature and weak sunshine, 35 rice genotypes including released cultivars and potential rice combinations were used as a tested materials, and two ecology-adaptive cultivars （Zhuyou606 and Qianyoul08） and two ecology-sensitive cultivars （Y Liangyou2 and Y I.iangyou302） were selected out as a tested materials to study the differences in grain yield and yield formation, nitrogen accumulation and distribution, root characteristics. The results showed that： when values were averaged across cultivars and years, compared with the ecology- adaptive cuhivars, the ecology-sensitive cultivars obtained a lower grain yield by 13.8%, which was mainly caused by a 9.9% lower filled grain ratio and 15.5% lower 1 000-grain mass. In comparison with the ecology adaptive cuhivars, the ecology-sensitive cultivars achieved 18.8%, 10.8%,14.5%lower nitrogen accumulation amount at the mid-tillering （critical stage of productive tillering）, heading, maturity stage, respectively, resulting in 17.9% lower nitrogen recovery efficiency （RE）. Furthermore, a higher nitrogen accumulation amount in stem-leaves at the heading stage and a lower nitrogen accumulation amount in stem-leaves at the maturity stage were found in the ecology-sensitive cuhivars, relative to the ecology-adaptive cultivars, and the nitrogen translocation amount from stems and leaves to panicle achieved 3.41 kg/667m^2 , which was 24.6% lower than that in the ecology adaptive eultivars,the nitrogen translocation ratio from stems and leaves to panicle achieved 38.55%, which was 19.4% lower than that in the ecology adaptive cuhivars. The root bleeding intensity of ecology-adaptive cuhivars achieved 20.2 kg/（h·667m^2） at the heading stage and 4.55 kg/（h· 667 m^2） at the maturity stage, which were 8.8% and 21.6 % lower than that in the ecology-adaptive cultivars, respectively. According to the results, a strategy to increase the grain yield of the ecology-adaptive cultivars is suggested： keeping a higher filled grain ratio and a higher 1 000-grain mass, which are able to be accomplished by increasing nitrogen accumulation during the growth period from heading to maturity. Moreover, these methods such as cultivating strong roots and improving root activity are helpful to increase the amount of nitrogen absorption.