Yield Analysis of Rapeseed (Brassica napus L.) Under Water-stress Conditions Using GGE Biplot Methodology

Identification of crop genotypes tolerant to drought stress will allow more extensive use of lands characterized as marginal because of water shortage in arid and semi-arid areas. Rapeseed (Brassica napus L.) is a dominant oilseed crop in Iran and has lower production risks compared with the other oilseed crops. Nine genotypes of rapeseed, including two Iranian cultivars and seven foreign, and their 36 F1 hybrids were used to determine the genetic parameters for seed yield under water-stress environment. Analysis of variance revealed significant differences for seed yield trait among studied genotypes under water-stress conditions. Genotypes differed significantly with respect to seed yield. In this paper, we used a GGE biplot approach of analyzing diallel design data. Parents SLM046, Okapi, and Orient had high positive GCAs, whereas parents Opera and Modena had negative GCAs in both years. Overall, the results of this study suggested that, within individual hybrid crosses, sufficient heterosis for yield existed to justify pursuing hybrid development in rapeseed. The SLM046 and Orient genotypes would be important for breeding programs designed for water-stress environments and in identifying drought-tolerant lines under arid and semi-arid conditions.