Analysis And Assessment Of Stability And Adaptility Of Buckwheat Variety

Buckwheat, origined from China, is distributed throughout the country, maily as a staple food in remote and poverty-stricken southwest and northwest China. Buckwheat is featured with infinite flowering and seed-setting character, hence low yield is obtained, moreover, buckwheat is grown in complicated environment compared with rice, wheat, maize and other major crops, and its performance restricted by geography, terrain, rainfall and temporal and spatial distribution, therefore, the interaction between genotype and environment is significantly dynamic, and yield fluctuation is observable, leading to low yield stability and weak local adaptability, which impedes development of buckwheat production.This study tried to find factors restricting buckwheat yield by analysis of correlation between yield and constitution elements and agronomic traits and path analysis. By employing statistical methods such as AMMI and other models, materials adpted in national buckwheat cultivar regional trials in 2003-2005 was slso analyzed to research on the productivity, stability and adatability of different genotypes. It got the following results:1.Correlation analysis between yield and agronomic traits showed that there was postitive relationship between grain weight per plant, 1000-kernels weight and yield, indicating improvement of the two agronomic characters could increase the yield. Path analysis showed direct path coefficient of 1000-kernels weight, grain weight per plant, node numbers of main stem, branch numbers of main stem to yield was positive respectively, and grain weight per plant, 1000-kernels weight, the two characters could take use of indirect positive role of other agronomic characters to improve yield, so it was important to take advantage of these two characters in buckwheat production; direct path coefficient of plant height, growth period to yield was negative respectively, which maybe resulted from the infinite growing habit and seed shattering character at the late stage.2.In Franics and Kannenberg model, average yield and variation coefficient, these two indexes were chiefly used to assess the productivity, stability and adaptability of varieties. The model had the advantage of simpilicity, easy calculation and popularity, but had the disadvantage of neglect of the interaction between variety and environment.3.In high stability coefficient method, HSC i was the mainly assessment index. The method was simple, easy to operate and powerfully practical, but just taking the genetic factor and environment factor into account individually and neglect of the interaction of them.4.In rank analysis method, one-way ANOVA and multiple comparison was conducted by using materials obtained in different environments, showing the significance between varieties, and then H1 Mi and H2 Mi, H2 i and S i2were computed to assess the productivity, stability, and adaptability of varieties. This method was simple and had clear meaning, but deletion of the invalid experimental site meant the neglect of variety yield at this site, possibly resulting in the uncertainty of the results.5.In Shukla model, the significance of F test and Shukla variation coefficient was used for assessment. This model was featured with simpilicity, clear meaning, good statistical performance, abundant information and accuracy, howerever, it was difficult to conduct homogeneity test and difference comparison, since the sum of interaction valueshould be null and the Shukla differences were not mutully independent.6.In AMMI model, Di and the distance between variety label and abscissa axis (or coordinate origin) in AMMI biplot was used to assess the stability and adptability of variety. AMMI Method owned the advantages of both variance analysis and principal components analysis, capable of showing the interaction, furthermore, by means of bioplot, the productivity, stability and adptability of variety could be evaluated directly, completely and effectively, and discriminating ability of each single site could be shown. However, when the elements of interaction error were eliminated, the true elements of interaction might also be eliminated, hence the intraction effect between year and variety could not be showed very well.7.When the stability and adaptability of buckwheat variety was evaluated, it was advised that integration of the above-mentioned methods and models was more desirable. Generally, the Franics and Kannenberg model and high stability coefficient method was primarily used to evaluate the productivity and stability, and then Shukla model was employed to evaluate the stability and adaptility of buckwheat accurately, searching for the desirable variety with high yield and wide adaptility. If the accuracy of variety estimation in each single site needs to be improved, the AMMI model could be adopted, together with bioplot and mean value chart for variety and site, the variety with high-yield, stability and adaptility in a large-scale area could be explored. In short, the stability and adaptility of buckwheat variety should be based on its productivity when analysis was conducted, and the stability indexes obtained using different methods should be understood correctly, and the assessment should be made on the basis of concrete analysis of varietity performance in different environment.8.By analysis of the materials about variety regional test in 2003-2005, it was showed that the control Pingqiao 2 performed better in stability and adaptility, and Liuqiao 1 perfromed poorly.