Investigation of Grain yield Stability in Canola (Brassica napus L.) Cultivars using GGE-biplot Method

Rapeseed is one of the most important oilseeds in Iran and the world. Due to Iran's dependence on imports of oilseeds and the existence of suitable conditions for the production of this product, it is necessary to determine stable genotypes in terms of grain yield and recommend the best genotypes for different environmental groups.

In order to study the effect of genotype and environment interaction, 10 rapeseed cultivars were planted in a randomized complete block design with three replications in five regions including Birjand, Karaj, Kashmar, Sanandaj and Shiraz and evaluated for grain yield in 2018-2019.

The results of combined analysis of grain yield showed that the effect of environment, treatment and genotype × environment interaction were significant. Environment, genotype and genotype × environment interaction accounted for 74, 12 and 14% of the total variance, respectively. Among the locations, the highest grain yield was related to Karaj with an average yield of 6.51 tons per hectare. Among the studied cultivars, the highest grain yield was related to Hyola401 and Okapi cultivars at 5.54 and 5.20 t / ha, respectively. The first and second components of GGE biplot explained 88.8% and 5.9% of grain yield changes, respectively. Simultaneous study of stability and performance base Bioplot method introduced Hyola401 and Opera genotypes as stable, high-performance genotypes. Using a biplot polygon view, six superior genotypes and three mega-environments were identified. Diagrams of relationships between cultivars classified the studied genotypes into two groups. The first group included Zarfam, Likord, Sarigol, Hyola401, Opera and Okapi genotypes and the second group included Hyola308, Modena, Option500 and Modena cultivars. Hyola401 and Opera genotypes In Karaj, Birjand and Sanandaj environments, Zarfam genotype in Kashmar and Okapi genotype in Shiraz were the most desirable genotypes. The Likord genotype had general stability to all environments.

In general, it can be concluded that Hyola401 genotype is more desirable than other genotypes and also Karaj region has a higher average yield among the studied environments.