Drought and Heat Stress Treatments

The plants were irrigated daily (∼100% field capacity) to prevent water deficit up to seed filling When the plants were at 75% podding (∼120 DAS in NS and 65 DAS in late-sown plants), drought stress was imposed by reducing soil moisture to 50% field capacity until maturity (15 days in both sowing environments) (Awasthi et al., 2014). Soil moisture was checked daily with soil moisture probe (Field Scout TDR 300 Probe, Spectrum Technologies, Inc., United States), and gravimeteric method periodically to maintain 50% field capacity.

Thus, there were the following four treatments:

Unstressed control (NS plants, fully irrigated to ∼100% field capacity)

Drought stress (NS plants, fully irrigated until 75% podding then maintained at ∼50% field capacity)

Heat stress (LS plants, fully irrigated to ∼100% field capacity)

Drought and heat stress (LS plants, fully irrigated until 75% podding then maintained at ∼50% field capacity)