Drought tolerance identification of interspecific hybrids from Brassica napus and Brassica juncea by subordinate function values

Drought tolerance was identified using 58 interspecific hybrids from Bassica juncea and Brassica napus.The object was to improve the drought tolerance of B.napus cultivar.Traits of drought tolerance included individual plant yield,main inflorescence yield and seed quality under drought stress in field.Subordinate function values method,cluster analysis and gray relevancy method were involved.Result showed significant correlations on both branch number and effective pod number to drought tolerance.Seed number per pod or 1 000-seed weight showed low correlation to drought tolerance.Under water stress,three traits of the main inflorescence were significant at 1% level among drought-resistance and drought-susceptible lines.These three traits were oil content,1 000-seed weight and protein content of main inflorescence.Among them,oil content and 1 000-seed weight in tolerance lines increased under drought,while protein content decreased.The correlation between three traits and single plant yield was greater than 50%.These three traits could be applied in preliminary selection for drought tolerance materials.Using the traits and methods above,these 3 lines 2007M004,2007M018 and 2007M027 were selected for high drought tolerance with average subordinate function values of at least 0.413.