Physiology of Drought tolerance in Sunflower

Sunflower occupies a prominent place among oil seed crops as it contributes about 12% to the world edible oil production. In India, sunflower is cultivated under rainfed situation, where intermittent moisture stress is most prevalent. If drought tolerant sunflower hybrid/varieties are developed, they can be grown successfully under water limiting conditions. This monographs deals with screening of sunflower genotypes under lab conditions using PEG-6000 to understand impact of stress at seedling stage. The genotypes were further screened under field by withholding water at flower bud initiation stage for morpho-physiological parameters. Selected 12 genotypes were evaluated under field conditions for plant height, TLA, SPAD chlorophyll meter readings, leaf fluorescence, total dry weight, photosynthetic rate, SLA, RWC, nitrate reductase activity and yield traits, which were declined with increase in stress and duration, whereas root characters, antioxidant enzymes (SOD and POX), canopy temperature and membrane injury increased. The identified sunflower genotypes can be used as parental lines in hybridization programmes for development of drought tolerant hybrids.