Direct-seeded upland rice is an important system of rice culture occupying almost 22% of the total rice area in India. In Assam, this crop is locally known as ahu rice (Mar/Apr-Jun/July). Assam farmers prefer this crop because this period is characterized by low rainfall, clear skies, and low frequency of floods. However, some constraints limit the widespread cultivation of ahu rice: uncertain rainfall; high evaporative demand, causing moisture stress; and weed infestation. Although the application of irrigation can solve the problem of moisture stress, scheduling of irrigation in upland situations where seed is sown in dry unpuddled soil is very difficult.
Hence, upland rice should have drought tolerance to withstand possible moisture stress in between irrigation schedules. Seed hardening with potassium salt before sowing helps induce drought tolerance in crops (Chinoy et al 1970).