## YIELD-FORMING COMPONENTS OF HIGH-YIELDING HYBRID-RICE

**Wu Zhi-qiang. Lin Fei Wu Tian-song**

Correlation analysis, analysis of covariance and partial regression equation analysis were used to evaluate the data obtained on 197 plots of paddy fields of maximum yield in order to clarify the yield components and the dynamic structures of rice population. The grain yields of these fields in 1978 and 1979 were all higher than 8250 kg/ha per crop. The results were summarized as follows: 1. Results obtained in both hybrids "Shan-you 2" and "Si-you 2" of the first or second crop under the multiple crop system indicated that the partial correlaton between the yield and the sum total of grains and between the yield and the percentage of ripe grains was significant. The values of the partial correlaton coefficient between the sum total of grains and the percentage of ripe grains and between the sum total of grains and 1000 grain weight showed negative significance. However, positive correlations between the sum total of grains and total full-grains were highly significant. Therefore, following the increasing of the sum total of grains, both hybrids gave increased yields, although the percentage of ripe grain and the weight of grain appeared somewhat being reduced. 2. The sum total of grains depended upon the number of available panicles multiplied by the basic numbers of grains per paaicle. 3. Significant positive correlation was found between the number of existed basic seedlings and the sum total of grains. In other words, with 15-120 thousand existed basic seedlings, the more the number of basic seedlings existed, the more the effective panicles were obtained and the more the available grain numbers. 4. According to the data obtained in this study, the number of seedlings to tillers and panicles inductive to high yield strcture is in the ratio of 1:3:2. Both hybrids "Shan-you 2" and "Si-you 2" had 20 million and 31 million grainsrespectively, producing 1050 kg. per hectare per crop.

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