关键词: 双季晚稻, 甬优系列, 籼粳杂交稻, 超高产, 群体形成特征

Abstract: 【Objective】Under the conditions of late rice of double cropping systems, Yongyou series of indica-japonica hybrid rice were used to investigate the structure and formation characteristics of super-high yield population. And it will provide a theoretical basis for cultivation of late Yongyou series of indica-japonica hybrid rice in double cropping systems. 【Method】A field experiment was conducted using the representative indica-japonica hybrid rice varieties Yongyou 538, Yongyou 2640, Yongyou 1540, and Yongyou 1538 to compare systematically yield and its components, development of stem and tiller number, development of leaf area and its composition, photosynthetic potential, dry matter accumulation and population growth rate between super-high yield and high yield populations formed by the regulation of cultivation measures. 【Result】Super-high yield population had more panicle and spikelets per panicle compared with high yield population. There was no significant difference in filled-grain percentage and 1000-grain weight between populations of super-high yield and high yield. Super-high yield population exhibited fewer tillers at the early growth stage and achieved expected number of stems and tillers at critical leaf-age for productive tillers, whose max number of stems and tillers was at jointing stage. Then, the number of population stems and tillers began to decrease stably, which achieved the expected number again. At last, the ratio of productive tillers to total tillers of super-high yield population was more than 75%, which was higher than that of high yield population. The leaf area index of super-high yield population was lower than that of high yield population, and the max leaf area index was about 8.1 at booting. Then the leaf area index of super-high yield population decreased stably, whose leaf area index, the ratio of effective leaf area, the ratio of effective leaf area and the ratio of grain to leaf were significantly higher than those of high yield population at heading and was above 3.5 at maturity. The photosynthetic potential of super-high yield population was small at early stage and larger at middle and late stages, as compared with high yield population. The total photosynthetic potential was above 580×10⁴ m²·d·hm^-2, of which more than 50.0% was from heading to maturity. The dry matter accumulation was smaller compared with high yield population before jointing, increased faster after jointing, and reached about 10.0 t·hm^-2 at heading and 19.0 t·hm^-2 at maturity, which was significantly higher than that of high yield population. Before the critical leaf-age for productive tillers, the population growth rate of super-high yield population was larger than that of high yield population, which was lower than that of high yield population from the critical leaf-age for productive tillers to jointing. After jointing, the population growth rate of super-high yield population was significantly larger than that of high yield population.【Conclusion】 With higher population started quality and earlier tiller, the population of super-high yield had obvious advantages, especially, higher photosynthetic matter production and greater dry matter accumulation in the middle and late growth stages. That building of enough total spikelets through adequate panicles and the large spikelets per panicle, and keeping a high seed-setting rate and 1000-grain weight are the suitable yield formation characteristics of rice under super-high yield cultivation.

Key words: late rice in double-cropping rice area, Yongyou series, indica-japonica hybrid rice, super-high yield, population formation characteristics