直播条件下行距对不同穗型粳稻产量及倒伏性状的影响

为探索直播条件下行距对不同类型粳稻产量的影响,以3种穗型粳稻品种通禾833、铁粳7号、沈稻506为试材,研究了直播粳稻在5个不同行距水平下的产量以及乳熟期(齐穗期后25 d)、蜡熟期(齐穗期后40 d)2个倒伏敏感时期水稻茎秆及穗部的物理性状和形态特征。结果表明:行距通过影响直播稻生长发育过程中行内、行间竞争关系,从而影响植株的物理性状和形态特征,改变群体结构,最终决定直播稻的产量和倒伏性状。通禾833在22.5 cm行距下产量最高,但随着行距减小,有效穗数、结实率降低,产量降低,且在低行距下弯穗型品种行间竞争激烈,造成群体郁闭、长势差、节间抗折力降低,从而易发生倒伏;铁粳7号17.5 cm行距下产量最高,且抗倒伏能力较强;沈稻506在行距20.0 cm时,协调了行内、行间的竞争,个体长势优良,群体结构合理,使其高产、抗倒。总之,过宽、过窄的行距分别加大了行间、行内竞争,从而影响植株个体长势及物理性状、群体结构,进而影响直播稻的产量及抗倒伏能力。因此,弯穗型品种应选用稍大行距(22.5 cm)、直立穗型品种选用稍小行距(17.5 cm)、半直立穗型品种选用中等行距(20.0 cm),通过协调行内和行间竞争,保证足够的单位面积有效穗数和较高的结实率,提高植株抗折力和基部节间弯曲力矩,构建合理植株个体形态和群体结构,以达到高产、抗倒的目标。

Effect of Row Distances on Yields and Lodging Resistance of Japonica Rice Cultivars with Different Panicle Types under Drill Seeding

To explore the effects of row distances on yield of different japonica rice cultivars with different types under drill seeding,with three different panicle types of japonica rice cultivars Tonghe 833,Tiejing 7,Shendao 506 as entries,the effect of five row distances on yield as well as physical properties and morphological characteristics of rice clum and panicle at milk (after heading stage 25 d)and dough stages(after heading stage 40 d),the two lodging sensitive stages,were studied under drill seeding condition.The results showed that with row distances changing the competition between the rows and in row was affected in the rice growth and development,which affecting the physical properties and morphological characteristics of plant,changing population structure,and eventually determining yield and lodging.As to Tonghe 833,the curved panicle cultivar,the highest yield appeared at 22.5 cm row distance,but with row distance decreasing,the productive panicle,seed setting rate and yield decreased meanwhile,in low row distance the between-row competition occurred fiercely,resulting in shading population,poor growing,decreasing breaking resistance between nodes and easy lodging;Tiejing 7 obtained the highest yield and stronger lodging resistance when the row distance was 17.5 cm;when at 20.0 cm row distance,Shendao 506 coordinated the competition in the row and between row,the individual plant grew well and the reasonable population structure was formed and the high yield and lodging resistance were realized.Briefly,too wide or too narrow row distance increased the competition between row and in the row,thereby affecting the physical properties of individual of plants,growth population structure,grain yield and lodging resistance.Above knowable,the seeds of curved panicle cultivars should be sown at larger row distance (22.5 cm),erect panicle cultivars at smaller row distance (17.5 cm),and semi-erect panicle cultivars at medium row distance (20.0 cm),and the high yield and lodging resistance could be easily reached through coordinating the competition between rows and in the row to ensure more productive panicles per unit area and higher seed setting rate,to improve breaking resistance and bending moment,and to build a reasonable individual plant morphology and population structure.