Physiological and biochemical traits of drought tolerance in Brassica juncea (L.) Czern & Coss.

• Differential response of 12 Indian mustard genotypes under rainfed and irrigated conditions were studied. • The results revealed a significant effect of drought on indicators of chlorophyll content, plant water status, sugars, proline concentration, antioxidative enzymes, malondialdehyde, oil yield and seed yield. • Relationship of proline, reducing sugars and oil yield with seed yield was relatively better under rainfed than irrigated condition. • JC 210-335, CSR 1163, MCN 09-40 and CJRD 1261 are the promising genotypes for developing drought tolerant mustard varieties. Global warming is elevating the risk of climate change which is increasing water scarcity, along with the population explosion and ever-expanding demands for food security resulting in the need for screening of drought tolerant genotypes which can be suitably grown both under rainfed and irrigated conditions. Brassica juncea (L.) Czern & Coss (Indian mustard) is one of the most important oilseed crops and is considerably affected by drought stress. In the present investigation, the impact of water stress on physiological and biochemical traits of advanced Indian mustard genotypes was studied. The experiment was conducted in factorial randomized block design accommodating 12 genotypes grown with two different irrigation modules, with only pre-sowing irrigation referred as rainfed /moisture stress and with two irrigations (35 and 65 days after sowing) referred as irrigated/normal. The results revealed a significant effect of drought on indicators of plant water status, sugars and proline concentration. The photosynthetic pigments (chlorophyll a and b, total chlorophyll and carotenoids) declined under rainfed significantly over irrigated condition. Relative water content decreased whereas water saturation deficit and relative saturation deficit increased under moisture stress as compared to normal condition. The proline, sugar levels and malondialdehyde content along with the antioxidative enzymes increased in all genotypes under stress. Seed yield, oil content and oil yield declined significantly due to moisture deficit. [ABSTRACT FROM AUTHOR]