Quality characteristics and drought tolerance evaluation of Brassica juncea in Yunnan Province.

To study the drought tolerance of Brassica juncea, quality of 150 local varieties of B. juncea was investigated in Yunnan Province. The aboveground and underground parts of the plants were studied under drought stress with different degrees. Results showed that B. juncea was tolerant to drought, and had wide range of quality variations. The variation coefficient of oleic acid and erucic acid was more than 1, and the varieties tested were roughly grouped into 3 categories according to quality characteristics. The medium and severe drought could significantly affect growth of shoot and root system, especially the root system. Under medium drought, drought tolerance had significant positive correlations with oil content and extremely long fatty acids (erucic acid and arachidonic acid), but had significant negative correlation with 5 long-chain fatty acids (stearic acid, palmitic acid, oleic acid, linoleic acid and linolenic acid). Under severe drought condition, drought tolerance had no relevance with quality traits. Meanwhile, drought resistance of the same variety was different under different degree of drought. Oil content had extremely significant positive correlation with long chain fatty acids. The oil content was negatively correlated with the content of long chain fatty acids and protein. The very long chain fatty acids had a significant negative correlation with long chain fatty acids. Eight varieties with strong comprehensive drought resistance were screened out. [ABSTRACT FROM AUTHOR]