多穗型杂交稻在不同肥力下生长与产量表现研究

Performance in Growth and Yield of Panicle-rich Hybrid Rice Under Different Fertilization Levels

通过对多穗型(明两优143)、大穗型(湘两优900)和中大穗型(丰两优4号)3个杂交稻品种在4种肥力水平(纯N用量0、150、225、300 kg/hm^(2))下的农艺性状、碳氮代谢关键酶活性和产量的表现进行研究,探索肥力水平对多穗型杂交稻的生长和产量的影响。结果表明,随着施肥水平的提高,3个品种的产量均同步提高,且肥力水平的提高对有效穗数、最高茎蘖数、株高、干物质量以及碳氮代谢关键酶活性均有促进作用,对结实率和成穗率有抑制作用,但对千粒重和每穗总粒数的影响不明显。多穗型品种明两优143在高肥水平(纯N用量300 kg/hm^(2))下达到3个品种中的最高产量,为9658.33 kg/hm^(2),其高产的主要原因是单位面积有效穗数的显著增加。多穗型品种明两优143齐穗期和乳熟期的地上部干物质量明显高于其他2个品种;其蔗糖磷酸合成酶(SPS)活性在花后第10天达最高值,比其他2个品种提早5或10 d,其硝酸还原酶(NR)活性在开花后第15天达到峰值,较其他2个品种延后5 d,这样使它能在灌浆期维持更长时间的较高酶活性水平,增强了光合能力,缩短了灌浆时间,从而保障其稳产高产。

Agronomic traits,key enzyme activities of carbon and nitrogen metabolism and yield of three hybrid rice varieties of panicle-rich type(Mingliangyou 143),large-panicle type(Xiangliangyou 900)and medium-panicle type(Fengliangyou 4)under four fertilization levels(pure N rates 0,150,225,300 kg/hm^(2))were studied to expound the effects of fertilization level on the growth and yield of panicle-rich hybrid rice.The results showed that with the increase of fertilization level,the yield of the three varieties increased simultaneously,and the increase of fertilization level promoted the number of effective panicles,the maximum number of tillers,plant height,dry matter weight and the key enzyme activities of carbon and nitrogen metabolism,and inhibited the seed setting rate and the panicle-bearing tiller rate,but had no obvious effect on the 1000-grain weight and the total number of spikelets per panicle.The panicle-rich variety Mingliangyou 143 reached the highest yield of 9658.33 kg/hm^(2) under the high fertilization level(300 kg/hm^(2) of pure N).The main reason for its high yield was the significant increase in the number of effective panicles per unit area.The above-ground dry matter weight of the panicle-rich variety Mingliangyou 143 was significantly higher than that of the other two varieties in full heading stage and milky ripening stage.Its sucrose phosphate synthetase(SPS)activity reached its highest value on the 10th day after flowering,five or ten days earlier than the other two varieties,and its nitrate reductase(NR)activity reached its peak on the 15th day after flowering,five days later than the other two varieties,which enabled it to maintain a higher enzyme activity level for a longer period of time during the grain-filling stage,enhanced its photosynthetic capacity,shortened the grain-filling duration and ensured the stable and high yield.