机插密度对不同类型水稻抗倒伏能力及产量的影响

以籼粳杂交稻品种甬优2640、甬优1640,杂交籼稻品种丰两优香1号、新两优6380为材料,设置6个密度(A:31.7 cm×30.0 cm、B:22.2 cm×30.0 cm、C:17.1 cm×30.0 cm、D:13.9 cm×30.0 cm、E:11.7 cm×30.0 cm、F:10.6 cm×30.0 cm),比较研究不同机插密度对不同类型水稻抗倒伏能力的影响。两年试验结果表明,产量随密度的增加呈先升后降的趋势,籼粳杂交稻和杂交籼稻均以13.9 cm×30.0 cm处理产量最高。密度对两种类型水稻影响也不完全一致,籼粳杂交稻在C~E密度下产量均高于10.5 t hm–2,且未发生倒伏或倒伏较少,能获得高产稳产;杂交籼稻只有在D密度下产量高于10.0 t hm–2,表观倒伏率较高,较难稳产。随着密度的增加,2个类型品种茎秆的倒伏指数逐渐增大,茎粗、单位节间干重、茎壁厚度都呈下降趋势。随着灌浆时间的增加,籼粳杂交稻倒伏指数先升高后降低,高峰值出现在抽穗后30 d,茎壁厚度、节间充实度、单茎茎鞘重先降低后升高,抽穗后30 d达最低值。杂交籼稻倒伏指数一直升高,茎壁厚度一直下降,节间充实度先下降,抽穗后30 d后略有下降或回升但不明显,单茎茎鞘重先降低后升高,抽穗后30 d最低,抽穗后30 d前后是发生倒伏的敏感时期。

Effect of Mechanical-Transplanting Density on Lodging Resistance and Yield in Different Types of Rice

In order to study impacts of planting density of mechanical-transplanting rice on lodging resistance and yield, a field experiment was conducted using Indica-Japonica hybrid rice Yongyou 2640, Yongyou 1640 and Indica hybrid rice Fengliangyouxiang 1, Xinliangyou 6380 with six planting densities (A: 31.7 cm × 30 cm, B: 22.2 cm × 30.0 cm, C: 17.1 cm × 30.0 cm, D: 13.9 cm × 30.0 cm, E: 11.7 cm × 30.0 cm, F: 10.6 cm × 30.0 cm). The experimental results were as follows. With the increasing of transplanting density, the yield increased firstly and decreased then, with the highest yield at 13.9 cm × 30.0 cm, both for Indica-Japonica hybrid rice and Indica hybrid rice. The effects of densities on the two types of varieties were not entirely consistent. Under the densities of C–E, the yield of indica-japonica hybrid rice was higher than 10.5 t ha^-1, and little or no lodging occurred. Therefore, we could obtain high and stable yield. Under the density of D, the yield of indica hybrid rice was higher than 10.0 t ha^-1, and the apparent lodging rate was also higher, so it was difficult to obtain stable yield. With the increasing of transplanting densities, lodging index of two types of rice increased, and stem diameter, wall thickness of culm and dry weight of a unit internode in two types of rice decreased. With increasing filling time, lodging index of indica-japonica hybrid rice increased firstly and decreased then, with the peak value at 30 days after heading, wall thickness of stem, plumpness of internode and single stem weight decreased firstly and increased then, with a minimum value at 30 days after heading. Lodging index of indica hybrid rice was increasing, stem wall thickness was decreasing, plumpness of internode decreased firstly then decreased or increased slightly at 30 days after heading, but not obvious, single stem weight decreased firstly and increased then, with a minimum value at 30 days after heading. The sensitive period of lodging was around 30 days after heading.