Study On Yield Formation Characteristics Of Different Super Hybrid Rice Varieties

Using Liangyoupeijiu, Y Liangyou No. 1, Y Liangyou No. 2, Y Liangyou 900, and Chaoyouqianhao as materials, the present study determined differences in yield components, tillering dynamics, dry matter accumulation and translocation, grain-filling rate, plant type, and panicle type of these five super hybrid rice cultivars, with aims to clarify characteristics of yield formation of super hybrid rice and to guide breeding and cultivation of super hybrid rice. Main results are as follows:Super hybrid rice non only had a great ability of spikelet differentiation, but also had a advantage in grain weights. High spikelet number increased the sink capacity and thus increased yields. In this study, Chaoyouqianhao had the highest sink capacity of 14.604t·hm-2, with actual yield reaching 13.623 t·hm-2 in combination with a high grain weight.Results showed that the key to obtaining high yield for super rice is to have both optimal panicle number and high spikelet number per panicle. Big panicle and small panicle number could reduce population competition, coordinate the relationship between individuals and population, thus improving population light transmission and maximizing light energy utilization of population and dry matter transport efficiency.Short basal internodes of stem, long internodes under the panicle, and great plant height contributed to great biomass production and optimized the configuration of the leaves. In this study, no significant differences in plant height and leaf length were observed among cultivars, whereas cultivars with high-yielding potential had greater leaf width than those with low-yielding potential. In addition, high-yielding cultivars had bigger angles of the upper three leaves, thus forming a more reasonable leaf configuration.No significant differences in biomass were observed among the cultivars, but high-yielding cultivars had higher efficiencies of nutrient transport and translocation, and thus had a greater contribution of stem biomass to yield with 49.30% for Chaoyouqianhao vs. 37.43% for Liangyoupeijiu. High-yielding cultivars showed greater chlorophyll content during the whole growth period than those with low-yielding potential. Effective leaf area index(LAI) did not significantly among these cultivars, but high-efficient LAI was greater for high-yielding cultivars than low-yielding counterparts. However, high-yielding cultivars showed markedly asynchronous grain filling, thus leading to a lower percentage of filled grains than those with low-yielding potential.