Preliminary Study On A Short Phyllochron Genotype In Vegetative Growth Stage In Rice

In this study, fourteen rice cultivars with middling length in growth duration from different sources were used, which of them,Yanhui559 Teqing . Minghui63 Jasmine85 Minghui86 R084 R6547. Yangfuxian2 R527 Zhenxianl22 R814 II-32 are of domestic indica type and Lemont and Cpslo17 belong to American long-grain cultivar. In 2003 and 2004, a sowing-stage experiment at different times was implemented continuously on the farm of Agriculture College of Yangzhou University. Growth duration from sowing to heading leaf number on caulis leaf emergence rate in average each day and number of elongating internode among different cultivars were investigated. According to the meteorological data of Yangzhou City and the growth duration, different cultivars' biological zero point temperatures were calculated. Regression and cluster analysis of growth durations and effective accumulated temperatures in the growth stage among cultivars were done. An F2 population was developed from the cross of Yanhui559 to Minghui63. The seedlings of the F2 population were separately transplanted according to the difference of caulis leaf emergence rates and the experiment was with two repeats. The tiller dynamic and characters related to yield in plots were investigated. The results are as follows:(1) A special indica genotype with a short phyllochron (Yanhui559) was found, which leaves exerted fast in vegetative growth stage. The growth duration of the genotype was nearly the same as the one of cultivars with a long phyllochron, such as Lemont, in a two-year experiment of sowing time. But the difference of caulis leaf number between the two types of cultivars was 4-5 leaves. The caulis leaf number of Minghui63 was between Yanhui559 and Lemont, and the difference between Minghui63 and Yanhui559 was highly significant, too.(2) The difference of leaf emerging rate among the three cultivars was highly significant in the criterion of either leaf number or leaf length grew each day, and the difference was mainly expressed in the vegetative growth stage.(3) Yanhui559 Lemont and Minghui63 all belong to the rice type of basic vegetative growth with middling length in growth duration. Based on the result of clusteringanalysis, three cultivars were similar in the effective thermal temperature accumulated in the whole growth stage, but the biological zero point temperatures of them were different significantly. Among them, the average available thermal temperatures required by each leaf emerged in different periods of growth was different, too.(4) An F2 population was developed from the cross of yanhui559 to minghui63. It was found that, in part of the population with character of short phyllochron, the stage of tillering peak came earlier relatively, the rate of panicles from tillers developed earlier was higher relatively, the average number of grains per panicle was more and the yield was higher than the long phyllochron part.(5) The number of elongated internodes among the three cultivars was significantly different and the correlation coefficient between the number of elongating internodes and the leaf number was significant.