Abstract:

In order to analyze the high-yield characteristics of ‘Yongyou’ series of late indica-japonica hybrid rice, we used ‘Yongyou 1540’ and ‘Yongyou 538’ to construct two populations with different yield levels, namely super-high yield and high yield, for continuous late rice cultivation. Their yield composition and population quality formation characteristics were investigated. The results showed that the average yield of super-high yield population reached 10.9 t/hm², which was 10.32% higher than that of high-yielding population. Among the yield components, the number of effective panicles of super-high yield reached 2.4528 million/hm², which was 6.25% higher than that of high yield, which was the main factor for increasing yield. The results also showed that, compared to high-yielding population, super-high yield population exhibited faster tillering initiation, lower peak seedling numbers, earlier timely seedling establishment, a gradual decline in stem-tiller numbers during late growth stages, higher effective panicle counts, and an elevated panicle-forming rate of 62.84%. The leaf area index of super-high yield population surpassed that of high-yielding population at the critical leaf-age stage for effective tillering, heading, and maturity stages, with a significant difference at the heading stage. Super-high yield population demonstrated superior dry matter accumulation primarily from transplanting to the critical leaf-age stage for effective tillering and from heading to maturity, outperforming high-yielding population by 20.51% and 20.99%, respectively. In summary, the super-high yield population of ‘Yongyou’ double-cropping late rice achieved high yield by optimizing population structure and strengthening material accumulation at key growth stages. The research results provided a scientific basis for high-yielding cultivation of double-cropping late rice in Ningbo and similar ecological areas.

Key words: late rice in double-cropping rice area, ‘Yongyou’ series, super-high yield population, leaf area index, panicle-forming rate, high-yield demonstration field