灌溉方式与施氮量对杂交粳稻颖花形成及籽粒充实的影响

为探讨不同灌溉方式与施氮量处理大穗型杂交粳稻穗粒数形成和籽粒充实的差异,以大穗型杂交粳稻甬优1538为材料,设置灌溉方式(W0:浅水层灌溉;W1:轻干湿交替灌溉)和施氮量(N1:施纯氮225 kg·hm~(-2);N2:施纯氮300 kg·hm~(-2);N3:施纯氮375 kg·hm~(-2))二因素试验,研究其对大穗型杂交粳稻稻穗颖花形成及籽粒结实性状的影响。结果表明,灌溉方式与施氮量对大穗型杂交粳稻稻穗总枝梗与颖花形成均有显著影响。与W0相比,W1显著增加了总枝梗与颖花分化数、退化数和现存数;3种氮肥水平下,N2的总枝梗数、颖花分化数和现存数最高,而退化数率最低。灌溉方式与施氮量对大穗型杂交粳稻枝梗与颖花形成的影响因着生部位不同而异。灌溉方式与施氮量对一次枝梗和颖花以及上部二次枝梗与颖花的影响均不显著,但在W1和N2条件下显著增加了中、下部二次颖花的分化数并减少退化数,促进了中、下部枝梗与颖花形成。灌溉方式和施氮量对强势粒千粒重和充实度的影响不显著,而对中势粒和弱势粒的千粒重和充实度的影响达显著水平,其中W1显著高于W0,N2显著高于N1和N3。在轻干湿交替灌溉条件下,N2有利于二次枝梗和颖花的形成,提高穗粒数的同时增加了籽粒粒重和充实度,从而提高了产量。本研究结果为大穗型杂交粳超高产栽培的养分水分管理提供了理论依据和实践指导。

Effects of Irrigation Pattern and Nitrogen Applications on Spikelets Formation and Grain Filling in Hybrid Japonica Rice

In order to investigate the difference of grain number and grain filling of hybrid japonica rice with large panicle under different treatments with water and nitrogen.Using Yongyou 1538 as test material,the effects of irrigation patterns (W0:water-saving irrigation,W1:alternate wetting and moderate soil drying) and nitrogen (N) rates (N1:225 kg·hm-2,N2:300 kg·hm-2,N3:375 kg·hm-2) on the spikelets formation and grain filling of hybrid japonica rice with large panicle were studied.The results showed that the formation of the total branches and spikelets was significantly influenced by the irrigation patterns and N rates.Compared with W0,the number of differentiated,retrograded and survived total branches and spikelets under W1 were significantly increased.The number of differentiated and survived total branches and spikelets at the N rate of 300 kg· hm-2 were the highest among the three different treatments of nitrogen,while the retrograded number and percentage were the lowest.The branch and spikelet formation of large panicle hybrid rice varied with their position at the rice panicle.The irrigation patterns and N rates had no significant effects on the formation of the primary and secondary branches and spikelets at the upper part of a panicle.But the W1 and N2 treatments significantly increased the differentiated number and decreased the retrograded number of secondary spikelets at the basal and middle part.It was worth noting that the differentiation and degradation of secondary spikelets at the basal part greatly affected the formation of the total spikelets.The irrigation patterns and N rates showed no significant effects on the 1000-grain weight and grain plumpness of superior grains,while significantly influenced those of medium and inferior grains.Combination of alternate wetting and moderate soil drying N2 could promote the formation of secondary branches and spikelets,increase the grain number per panicle,grain weight and plumpness.This study provides a theoretical basis and practical guidance for the high yield cultivation and water and nutrient management of hybrid rice variety with large panicle.