双季直播水稻的产量形成及群体光合基础研究

Yield Formation and Population Photosynthetic Basis of Double-Cropping Direct Seeding Rice

为了发掘直播风险较小的品种,推荐较好的早晚稻直播品种搭配模式,选用当前种植面积较大的早稻品种中早39、湘丰早119、湘早籼6号和湘早籼32号为试材,开展了早晚双季直播水稻产量形成及群体光合基础的研究。结果表明:在直播密度为5.0 kg/667m2的条件下,4个品种的产量均可达到移栽种植的平均水平,其中,早晚双季直播时湘早籼6号的两季生育期为172 d、双季产量为726.0~884.7 kg/667m2,湘早籼32号的两季生育期为177 d、双季产量为784.3~847.2 kg/667m2,湘丰早119的两季生育期为172 d、双季产量为794.1~990.5 kg/667m2,这3个品种作早晚双季直播时生育期搭配合适,可以在适合的地区推广;中早39和湘丰早119的光合速率较强且后期下降幅度相对较小,其齐穗后最大输出量和乳熟期至成熟期的群体生长率均显著大于其他2个品种,且中早39分蘖期至抽穗期的群体生长率最大、湘丰早119抽穗期到乳熟期的群体生长率显著大于其他品种,这2个品种表现出较好的产量潜力;中早39的每穗粒数多、产量较高,但生育期相对较长,而湘丰早119的生育期短,属于多穗、稳产品种,推荐采用中早39+湘丰早119的早晚双季直播模式。

In order to find low-risk direct seeding rice cultivars and offer a suitable combination pattern between early and late rice cultivars,an experiment of exploring the yield formation and population photosynthetic basis of double-cropping direct seeding rice was conducted with early rice cultivars Zhongzao 39,Xiangfengzao 119,Xiangzaoxian 6 and Xiangzaoxian 32 planted on a large scale currently.The results showed that at a direct seeding density of 75.0 kg/hm2,the yield of the four varieties could reach the average level of transplanting.Among them,Xiangzaoxian 6 was of a 172 d double-cropping growth period,and 10,890.0-13,270.5 kg/hm2 of double-cropping yield,Xiangzaoxian 32 was 177 d and 11,764.5-12,708 kg/hm2,and Xiangfengzao 119 was 172 d and 11,911.5-14,857.5 kg/hm2;these three varieties are well matched in the growth period for early and late double cropping and can be promoted in suitable regions.The photosynthetic rates of Zhongzao 39 and Xiangfengzao 119 were stronger and decreased less in the later period;meanwhile,their maximum output after full heading and population growth rates from milk ripening to maturity stages were significantly higher than those of the other two varieties;the population growth rate of Zhongzao 39 was the largest from tillering to heading stages,while Xiangfengzao 119 was significantly higher than the other two varieties from heading to milk ripening stages,both of which showed better yield potential;and Zhongzao 39 had more grains per panicle and higher yield,but its growth period was relatively longer,while Xiangfengzao 119 had a short growth period with multiple panicles and stable yield,so it is recommended to adopt the double-season direct cultivation mode of Zhongzao 39+Xiangfengzao 119.