Assessment of yield, yield components and early maturing in six species of Brassica

In order to identify important agronomic traits related to yield and introduce early with high-yielding cultivars in Brassica genus, 100 genotypes of six species of Brassica genus (B. napus, B. juncea, B. nigra, B. rapa, B. carinata and B. oleracea)were evaluated implementing latis square designs with two replications experiments at Sari Agricultural Sciences and Natural Resources University Research Farm during 2017-2018. The results of variance analysis showed that the studied genotypes have very significant differences with each other in terms of all agricultural traits. The results of mean comparison showed that genotypes from B. napus species has the highest yield and genotypes from B. rapa species has the shortest days to ripening with the lowest yield. The longest days to ripening was identified as genotypes from B. juncea species. The analysis of genetic correlations for all species revealed that yield of seed had a significant positive correlation with days to ripening, silique number per plant, thousand grian weight and grian number in silique. Results of stepwise regression analysis revealed that silique number per plant, 1000-grain weight, number of silique per plant and days to maturity had significantly effects on grain yield. The result of factor analysis showed three independent factors that explained 92% of the total variability, which were named ‘productivity’, ‘phenology’, and ‘thousand grian weight’, respectively. According to all three factors, B. napus, best species and Janetzika، Liragold، Hayola 401and Hayola 308 from B. napus species, were identified as the best cultivars concerning seed yield and early maturity.