Characteristics of Super-high Yield Population in Yongyou Series of Hybrid Rice

Abstract

A field experiment was conducted using the representative indica-japonica hybrid rice Yongyou 11, Yongyou 12,Yongyou 13, Yongyou 15, and Yongyou 17 to compare between super-high and high yield populations formed by the regulation of cultivation measures. The results showed that the spikelets of the super-high yield population was higher than that of high yield population, with difference very significant, but the seed-setting rate and 1000-grain weight of the super-high yield population were lower than those of high yield population. The average spikelets per panicle was significantly higher than that of high yield population, meanwhile the number of the primary and secondary branches and total grains were higher than those of high yield population, showing a significant or very significant difference. The dry matter accumulation of the super-high yield population was a little lower than that of the high yield population at the jointing stage, but higher at heading and maturity stages. From the critical leaf-age for productive tillers to jointing stage, the super-high yield population had a steady growth with less ineffective tillers and lower peak number of tillers after jointing stage, the super-high yield population had a steady decline in number of tillers and had higher productive tillers rate, leaf area index, photosynthetic potential and dry matter accumulation, compared with the high yield population. The super-high yield population had higher culm diameter and culm wall thickness in the basal first, second and third internodes, as well as higher bender moment and anti-broken strength, and lower lodging index than the high yield population.