Comparing durum wheat cultivars by genotype x yield x trait and genotype x trait biplot method

Abstract

The specification of the most convenient cultivars based on multiple trait indices is a new approach in durum wheat (Triticum durum Desf.) adaptation and stability studies. This approach helps to define the best cultivar based on multiple traits and multiple locations because cultivars are affected by unpredictable climatic conditions. Some traits (ears per square meter, spike length, number of grains per spike, spike yield, and leaf chlorophyll content among others) can be produced for primary breeding purposes because they are influenced by environmental factors and indirectly affect grain yield and quality. Therefore, in the present study, the new genotype × yield trait (GYT) biplot approach was used to identify the best cultivar among 10 durum wheat cultivars based on multiple environments (8) and multiple traits (18). Cultivar ranking was examined by a superiority index that combined yield and other target traits with the GYT biplot. The general adaptability of each cultivar in terms of all the traits indicated differences based on environment means, and significant differences were found between varieties for the GYT biplot. In the GYT biplot, yield-trait combinations clearly indicated the most stable cultivars, whereas in the genotype × trait (GT) biplot, the best cultivars were not defined for all traits. ‘Sariçanak’ was ranked as the best combination of physio-morphological traits with grain yield, ‘Zühre’ was the best for more quality traits, and ‘Güneyyildizi’ was the best for both physio-morphological and quality traits in the GYT biplot. The GYT biplot combines traits with yield and can help the visual identification of the best cultivars; it is better than the GT biplot method.