四川盆地东南部气象因子对杂交中稻产量的影响

为了探明四川盆地东南部气象因子对杂交中稻产量的影响, 并提出相应的丰产技术对策。2015年和2016年, 以2个杂交中稻品种II优602和旌优127为材料, 在5个播种期和高氮低密与低氮高密2种栽培方式下, 研究了四川盆地东南部气象因子对杂交中稻产量的影响。结果表明, 随着播种期推迟, 平均全生育期从148.13 d逐渐缩短到123.25 d, 缩短了14.77%; 气象因子对水稻全生育期的影响主要在营养生长期, 生殖生长期受其影响较小。年度间、栽培方式间、品种间稻谷产量差异均不显著; 随着播种期推迟, 稻谷产量呈下降趋势, 从3月5日的8507.76 kg hm^-2下降到5月24日的6251.01 kg hm^-2, 降低了26.53%。播种-移栽、移栽-拔节、营养生长的日数和全生育期日数分别与穗粒数和产量呈极显著正相关。气象因子对产量的影响在不同年份和不同品种间的表现不一致: 优质稻旌优127 2015年的结实率、千粒重和产量分别与齐穗-成熟的日平均气温呈极显著正相关, 分别与拔节-齐穗的日照时数呈显著负相关; 2016年的穗粒数、产量分别与播种—移栽日最高气温、移栽—拔节的日平均气温呈极显著负相关。高产品种II优602, 2015年的有效穗、千粒重和产量分别与移栽—拔节的降雨量呈显著或极显著负相关, 2016年的穗粒数和产量分别与移栽-拔节的日最高气温呈显著或极显著负相关, 结实率、千粒重和产量分别与拔节-齐穗的日平均相对湿度呈显著正相关。生产上一季中稻模式的最佳播种期在3月5日至3月25日, 而中稻-再生稻模式则在3月5日至3月25日期间尽可能早播, 以利于提高再生稻安全齐穗保证率。

Effects of Climatic Factors in the Southeast of Sichuan Basin on Grain Yield of Mid-season Hybrid Rice

The aim of this study was to clarify the key climatic factors influencing rice yield, and propose the technical measures for rice yield increase in southeast Sichuan Basin. A field experiment with two hybrid rice cultivars, II you 602 and Jingyou 127, was conducted to study the effect of climatic factors on yield increasing in water-logged paddy field of this area in 2015 and 2016. In each year, the two cultivars were grown in two combinations (high nitrogen rate with low plant density, HNLD; low nitrogen rate with high plant density, LNHD), respectively, on five sowing dates. As the sowing date delayed, the mean whole growth duration of hybrid rice was shortened by 14.77%, from 148.13 d to 123.25 d. Vegetative period of hybrid rice, rather than the reproductive period, was mainly affected by climatic factors. Grain yield of hybrid rice was not significantly affected (differentiated) by year, cultural method and cultivar. Grain yield of hybrid rice dropped from 8507.76 kg ha^-1 on March 5 to 6251.01 kg ha^-1 on May 24. The average grain yield of hybrid rice across five sowing dates was reduced by 26.53%. Growth duration from sowing (SO) to transplanting (TR), TR to jointing stage (JS), number of days in vegetative period and whole growth duration, respectively, had a significantly positive correlation with spikelets per panicle and grain yield. The effects of climatic factors on grain yield of hybrid rice varied with years and cultivars. For good quality rice Jingyou 127, percentage of filled grain, thousand-grain weight and grain yield, respectively, were significantly and positively correlated with average diurnal temperature from full heading (HD) to maturity (MA), while significantly and negatively correlated with sunshine hours from JS to HD in 2015; spikelets per panicle and grain yield, respectively, had a significantly negative correlation with average maximum temperature from SO to TR and average diurnal temperature from TR to JS in 2016. For high-yielding cultivar II you 602, panicles per m², thousand-grain weight and grain yield, respectively, were significantly or extremely significantly and negatively correlated with precipitation from TR to JS in 2015; spikelets per panicle and grain yield, respectively, were significantly or extremely significantly and negatively correlated with daily maximum temperature from TR to JS, while percentage of filled grain, thousand-grain weight and grain yield, respectively, were significantly and positively correlated with average relative humidity from JS to HD in 2016. In conclusion, the optimum sowing dates in southeast Sichuan Basin are from March 5 to March 25 for single mid-season hybrid rice. Meanwhile, sowing as early as possible during the optimum sowing period will be more beneficial to the improvement of guarantee rate for safe full heading of ratoon rice in main crop-ratooning rice system.