关键词: 马铃薯晚疫病, 马铃薯晚疫病, CARAH预警模型, 四川, 春马铃薯

Abstract: To discuss the effects of sowing date on the growth, development and yield and quality of rice and to establish the optimum sowing date range are of certain significance for guiding rice production practice in cold regions. The experiment is carried out in filed, and‘Kongyu131’was used as the experimental material. Seven kinds of sowing dates were set up. The effects of sowing date on tillering dynamics, dry matter accumulation and yield formation of rice were analyzed. The results showed that there were significant differences in tiller number, panicle rate, dry matter accumulation, yield and its composition with different sowing dates. B2, B3 and B4 treatments significantly increased yield, effective panicles per square meter, seed setting rate, grain number per panicle and grain weight; the actual yield increased by 18.12%, 17.70% and 14.92% compared with B1, increased by 41.38%, 40.89% and 37.56% compared with B7, respectively. The effect of B2 treatment was the best, followed by that of B3. Compared with other treatments, B2, B3 and B4 treatments had higher leaf area index, more dry matter accumulation, and could form high quality population. They had higher spike rate, seed setting rate and grain number per spike, and had strong complementary effect among yield components, and ultimately improved grain yield and milling quality. In contrast, sowing too early or too late could lead to significant or extremely significant decrease in dry matter accumulation, panicle formation rate, seed setting rate and yield, and it was not conducive to the improvement of milling quality. Late sowing could significantly or extremely and significantly reduce chalky grain rate and chalkiness. The comprehensive analysis shows that the sowing date between April 10 and 20 is more suitable for high yield and high efficiency rice cultivation in cold region.