Analysis On Productivity And Quality Characters Of Japonica Rice And Study On Evaluation And Utilization Of Germplasm

In this study 279 rice germplasm resources were collected from Heilongjiang, Liaoning, Tianjin, and Jiangsu. Field observations, physical and chemical tests and statistical analysis were carried out. The correlations between the traits and the main deciding factors affecting grain yield and quality were investigated. Identification, evaluation and selection of germplasm resources with specific traits were done. The results of this study provide some theoretical and practical guidelines for the breeding of rice of both high productivity and quality. The main results are as follows:1. Rice yield per plant was significantly positively correlated with grain density, grain weight, ratio of grain to straw, effective panicles per plant, seed setting rate, SPAD at full heading stage, was significantly correlated with grains per spike. Full heading stage and grain yield per plant leaf color value of the correlation was highly significant, from the full heading of the leaf color value can determine the initial yield of rice plant. SPAD at full heading stage was most significantly related to grain yield per plant, so the latter could be preliminarily predicted by the former.2. The main factors determining rice yield were: grains per spike, grain density, grain length, seed setting rate, panicles per plant. The cumulative contribution of these factors to yield is 81.58%.3. The three processing quality traits of rice showed significant positive correlations with each other, milled rice length was the most important factor affecting the head milled rice rate, and milled rice thickness the most important factor affect milled rice rate. Japonica chalkiness rate and chalkiness degree showed significant positive correlations and both of them were significantly negative correlated with head milled rice rate. Milled rice whiteness degree was an important factor affecting the processing quality and appearance quality of rice,the whiteness degree value can be determined by a grain evaluation instrument, by the results of whiteness degree value, the processing quality and appearance quality could be inferred.4. The main factors determining comprehensive quality of rice were: processing factor (milled rice rate, brown rice rate), the appearance factors (chalkiness rate, chalkiness degree), cooking factor (AC), and palatability factor (palatability value). The cumulative contribution of all these factors to comprehensive quality of rice was 77.30%.5.The RVA spectrum determined by rapid visco-analyser could be used to predict characters like amylase content, alkali spreading value, rice appearance, viscosity, rigidity, palatability value, physical property balance, flexibility, etc.6. SPAD at full heading stage was significantly positively correlated with PC, rice rigidity value, physical property balance, chalkiness rate, chalkiness degree, significantly negatively correlated with ASV, AC, palatability value, the viscosity of rice, the appearance quality. Plant height was significantly positively correlated with ASV, AC, head milled rice rate. Seed setting rate was significantly positively correlated with brown rice rate, milled rice rate and head milled rice rate. Grain per spike was significantly positively correlated with Whiteness degree, chalkiness rate and chalkiness degree. Grain yield per plant was significantly positively correlated with PC, chalkiness rate, chalkiness degree, brown rice rate, milled rice rate and head milled rice rat. Effective panicles per plant was significantly positively correlated with the PC, AC and brown rice rate, significantly negatively correlated with physical property balance whiteness degree. 1000 grain weight was significantly positively correlated with brown rice rate, milled rice rate and head rice rate. Ratio of grain to straw was significantly positively correlated with PC, chalkiness rate, chalkiness degree, milled rice rate. SPAD at full heading stage showed significant or highly significant positive correlation with 11 quality traits, and it can be used as an indicator of these traits for the early selection of rice.7. The main factors determining rice palatability value were: cool paste viscosity, palatability-related indicators, SPAD at full heading stage, plant height, PC and AC, grain length, thickness, spike length and milled rice rate. The cumulative contribution of all these factors to rice palatability value was 81.701%.8. Based on the dominant factor of production, quality, palatability, all the germplasm was assessed according to Feng Zhenghua(1990) and"The evaluation of excellent and special rice germplasm". 14 special collections were selected ,including materials with dwarf height, more effective panicles per plant and more grains per spike and high yield per plant, high 1000-grain weight, small SPAD at full heading stage, high brown rice rate, high head rice rate, low chalkiness rate, low protein content, low amylase content, and high palatability value, better amylase character. Each type of resources included some special materials, some of them were materials with excellent agronomic traits and quality traits. These materials can be used as the parents in breeding programs on productivity and quality and candidates to the regional promote testing for high-quality Japonica rice.