播期对川西平原直播稻光合特性和产量的影响

为合理搭配川西平原稻田两熟区直播稻品种和播期,通过中早熟、中熟、中迟熟3个杂交稻分期播种试验,研究各品种水稻光合特性、产量及其构成因素的差异。结果表明,3种籼稻的净光合速率(Pn)随着播期推迟总体均呈下降趋势;播期推迟显著降低了中熟和中迟熟品种的有效穗数和结实率,导致产量显著下降(P<0.05);播期过早或过迟均不利于中早熟品种产量性状的协调发展。中熟和中迟熟品种产量受播期影响较大,而中早熟品种大部分播期内差异不显著;3个品种产量降幅分别为11.8%、33.0%、45.4%。综上,为保障川西平原直播稻产量,3种类型籼稻适宜播期应在4月5日-26日间。中早熟品种内5优玉香1号可适当推迟播期,适合作为当地麦-稻或油-稻两熟制直播稻品种推广应用。本研究为川西平原稻田两熟区直播稻适宜播期和品种选用提供了参考依据。

Effects of Sowing Date on Photosynthetic Characteristics and Yield of Direct Seeding Rice in Western Sichuan Plain

Aimed to arrange direct seeding rice varieties and sowing date properly, a phased field experiment was conducted in paddy fields of Western Sichuan Plain, to evaluate the differences of photosynthetic characteristics, yield and its constituent factors of 3 representative hybrid rice varieties. The results showed that along with delayed sowing date, the net photosynthetic rate (Pn) of 3 rice varieties decreased generally. Meanwhile, the effective panicle number and seed setting rate of medium and late maturing varieties significantly decreased, leading to significant decline of their yield (P<0.05). Early or late sown conditions were not conducive to the coordinated development of the yield of early maturing variety. The yield of medium and late maturing varieties dramatically affected by the delayed sowing date. However, there were not significant differences in most selected sowing date of early maturing variety. The yield of 3 cultivars decreased by 11.8%, 33.0% and 45.4% from highest to lowest, respectively. Overall, to ensure stable and high yield of direct seeding rice in Western Sichuan Plain, the suitable sowing date of 3 varieties could be April 5^thto 26^th. Furthermore, the results suggested that the early maturing variety Nei5youyuxiangⅠ could be appropriate to postpone the sowing date, which was suitable for the application of local wheat-rice or rape-rice rotation systems. This study provided reference for the suitable sowing date and variety selection of direct seeding rice in paddy field of Western Sichuan Plain.