Evaluation of upland cotton yield stability and adaptability using GGE-biplot analysis: A case study of 'Ezamian 30' cotton cultivar in Yangtze River Valley

The major challenge for a breeder is choosing genotypes with high yield and stability, which have always been the main objectives of crop yield breeding. However, the ever-existing genotype-by-environment interaction has also always impeded the progress in selecting new cultivars for a wide spectrum of the environment. Scientific and reasonable assessment of the stability and adaptability of varieties are conducive for improving the selection and utilization efficiency of crop breeding. In this study, the GGE-biplot^® software was used to explore and visualize yield ability, stability and adaptability of a newly registered cotton cultivar 'Ezamian 30' and other candidate lines in the same groups of national cotton trials during the period 2012-2013 in the Yangtze River Valley (YRV). Meanwhile, the "Pairwise Comparison view" of the GGE biplot was used for one-to-one comparison with the control cultivar 'Ezamian 10' for superiority of adaptability to the local conditions. The results showed that: 1) 'Ezamian 30' had a prominent high-yield and an excellent stability in the 2-year multi-environmental variety trials. 2) The integrated performance (i.e., ideal index) of 'Ezamian 30' in joint evaluation of high yield and stability was significantly superior to that of the control 'Ezamian 10' and other candidate lines in the trials. 3) The dominant suitable planting area of 'Ezamian 30' was widest among all candidate cultivars, which covered an overwhelming majority of the whole cotton planting region in YRV. 4) For one-to-one comparison, 'Ezamian 30' evidently had a beneficial planting advantage with higher yield potential than the control cultivar and other candidate lines in most of cotton growing area in YRV. This study demonstrated the effectiveness of GGE-biplot in the concurrently evaluating high yield/stability, suitable planting area delineation, etc. Furthermore, it showed the ideal characteristics of 'Ezamian 30' for high yield, stability and adaptability. Thus it provided not only theoretical guidelines for reasonable extension and utilization of 'Ezamian 30', but also set up a reference base for comprehensive evaluation of other varieties and/or crops.