Difference in Yield and Population Characteristics of Different Types of Late Rice Cultivars in Double-cropping Rice Area

Abstract

In order to provide the scientific basis and technical support for the selection of suitable cultivars and high-yielding cultivation in double cropping systems, we selected indica-japonica hybrid rice, japonica hybrid rice, japonica conventional rice and indica hybrid rice in double-cropping rice areas(Shanggao of Jiangxi) in the middle reaches of the Yangtze River to analyze the differences of yield and its components, development of stem and tiller number, development of leaf area and its composition, photosynthetic potential, dry matter accumulation, crop growth rate and net assimilation rate of rice cultivars with different types systematically using wet nursery and big seedlings transplanting under high-yielding cultivation condition. Results showed that the yields of different types of late rice cultivars in double cropping systems all demonstrated indica-japonica hybrid rice ja-ponica hybrid rice japonica conventional rice indica hybrid rice very significantly. Establishing enough total spikelets through adequate panicles and large spikelets per panicle, and keeping a sustainable seed-setting rate and 1000-grain weight on the basic way to obtain the highest yield for indica-japonica hybrid rice. Compared with japonica hybrid rice, japonica conventional rice and indica hybrid rice, indica-japonica hybrid rice showed fewer tillers at the early growth stage, achieved expected number of stems and tillers at the critical leaf age for productive tiller, and had lower number of peak tiller at the jointing stage. Then, the indica-japonica hybrid population had a steady decline in number of tillers with a higher productive tillers rate(about 73.19%). The leaf area index of indica-japonica hybrid rice population was lower at the early growth stage, with the maximum leaf area index of about 7.93 at booting, and kept more than 3.85 at maturity, whose leaf area index, the ratio of effective leaf area, ratio of effective leaf area in top three leaves and ratio of grain to leaf were significantly higher than those of japonica hybrid rice, japonica conventional rice and indica hybrid rice population at heading. The dry matter accumulation of indica-japonica hybrid rice was comparable to that of japonica hybrid rice, japonica conventional rice and indica hybrid rice population at the critical leaf age for productive tiller and at the jointing stage, increased greater after jointing, and was higher at booting, heading, milky stage and maturity. The proportion of total biomass accumulation was higher at the middle and late growth stage. The photosynthetic potential, crop growth rate and net assimilation rate were smaller at the early stage and higher at the middle and late stages.