Study On Yield And Quality Of Indica Hybrid Rice In Different Altitude And Latitude In Yunnan

Rice yield and quality are influenced by heredity and ecological conditions.The diverse ecological conditions bring more requirements and challenges to the improvement of rice yield and quality.In order to understand the influence of altitude and latitude of on yield and quality of hibryd rice,nine indica hybrid rice combinations were used as experimental materials and grown in 5 sites in Yunnan Indica-planting zones with different latitudes and altitude,then we investigated and analyzed the yield,economic traits,rice grain quality and RVA spectrum eigenvalues of nine hybrid combinations and obtained the following main results:1.The yield and main economic traits,were influenced not only by genetic background but also by environmental conditions.Compared with Yunguang14,C5,Liangyoupeijiu and C10,Y-liangyou1 hao,Zhunliangyou527,Gangyou725 and Yunguang17 had higher yield in different ecological conditions.The average yield of these indica hybrid combinations were 17.59%,16.34%,16.87% and 12.18% higher than the yield of control varietyⅡyou838.Their plant height was between 105-110 cm,number of effective panicles per plant was over 8,number of filled grain per panicle was over 150,seed setting rate was over 83%,1000-grain weight was between 28-33 g.Number of days from transplanting to heading was approximately the same in 5 sites with different latitudes and altitude,number of days from sowing to transplanting was the main reason for the different growth period of tested indica hybrid rice.2.The results of correlation analysis on the yielding traits measured in different latitudes and altitude areas showed that number of filled grain per panicle was positively correlated with yield;the results of path analysis showed that the number of filled grain per panicle contributes the most to yield(contribution rate was 1.0199);the results of factor analysis showed that the first factors of econonic traits of the tested indica hybrid combinations were different in 5 sites with different latitudes and altitude.3.The head rice rate of the tested indica hybrid combinations reached first grade based on edible rice grading standard(NT/T593-2002);the grades of appearance,cooking quality and eating quality were different for different varieties.The effects of latitudes and altitude on rice quality could be divided into two categories: brown rice rate,milled rice rate,head rice rate,amylase content,alkali digestion value and gel consistency belong to insensitive type,chalkiness rate and rice chalkiness ratio belong to sensitive type.The results of factor analysis showed that the first factors of rice grian quality traits of the tested hybrid rice varieties were different in 5 sites with different latitudes and altitude.4.When the altitude difference between two ecological areas was less than 200 m and latitude difference was less than 1°23′,the differences of growth period,plant height,number of effective panicles per plant,number of filled grain per panicle,seed setting rate,1000-grain weight,head rice rate,chalkiness rate,rice chalkiness ratio,amylase content and gel consistency of same indica hybrid combinations were not significant,but the difference of RVA characteristic spectrum was significant.5.When the altitude difference between two ecological areas was more than 200 m and latitude difference was less than 1°23′,the yield,growth period,number of filled grain per panicle and seed setting rate of the tested indica hybrid combinations increased while altitude increasing,but plant height,number of effective panicles per plant and 1000-grain weight decreased;head rice rate and amylase content increased while altitude increasing,but chalkiness rate,rice chalkiness ratio and gel consistency decreased.6.When the altitude difference between two ecological areas was less than 200 m and latitude difference was more than 1°23′,the yield,growth period,plant height,number of filled grain per panicle and seed setting rate of the tested indica hybrid combinations increased while altitude increasing,,but number of effective panicles per plant and 1000-grain weight decreased;head rice rate,chalkiness rate,rice chalkiness ratio and gel consistency increased while altitude increasing,but amylase content decreased.7.The effects of rice starch RVA characteristic spectrum of the tested indica hybrid combinations in different latitudes and altitude conditions could be divided into two categories: peak viscosity,hot paste viscosity,cool paste viscosity,breakdown viscosity and consistence viscosity were insensitive type;setback viscosity was sensitive type.The results of multiple regression analysis and partial correlation analysis on the rice starch RVA characteristic spectrum of the tested combinations in different altitude and latitude conditions showed that,the partial correlations between peak viscosity,hot paste viscosity,cool paste viscosity,breakdown viscosity,setback viscosity,consistence viscosity and altitude and latitude among different hybrid rice combination were different.8.The correlation between rice grain quality traits and rice starch RVA characteristic spectrum was: milled rice rate was negatively correlated with peak viscosity and breakdown viscosity,but positively correlated with setback viscosity and consistence viscosity;head rice rate was negatively correlated with breakdown viscosity,but positively correlated with cool paste viscosity,setback viscosity and consistence viscosity;chalkiness rate were positively correlated with peak viscosity,hot paste viscosity,cool paste viscosity and consistence viscosity;rice chalkiness ratio were positively correlated with peak viscosity,hot paste viscosity and cool paste viscosity;amylase content was negatively correlated with peak viscosity and breakdown viscosity,but positively correlated with cool paste viscosity,setback viscosity and consistence viscosity;gel consistency was negatively correlated with cool paste viscosity,setback viscosity and consistence viscosity,but positively correlated with peak viscosity and breakdown viscosity.9.According these results,the yield of 9 tested indica hybrid combinations was different in planting area with different altitude and latitude.If the latitude difference of ecological areas was less than 1°23′,Yunguang17 was suitable to be planted in high altitude areas such as Yuanyang(1550m),but Gangyou725 was suitable to be planted in low altitude areas such as Jinghong(550m);if the altitude difference of ecological areas was less than 200 m,Zhunliangyou527 was suitable to be planted in high latitude areas such as Shuifu(28°33′),but Gangyou725 was suitable to be planted in low latitude areas such as Jinghong(21°58′).