Seed priming improves irrigation water use efficiency, yield and yield components of summer cowpea under limited water conditions

A split plot design field study was conducted during summer month of 2012 and 2013 at the vegetable block of Indian Institute of Horticultural Research in Bangalore, India to evaluate if priming could improve grain yield and water use efficiency of cowpea under limited water supply condition through drip system. Seeds of cultivar Arka garima received the following priming treatments: they were soaked in GA3,Calcium Chloride, Ammonium Molybdate, Potassium Bromide, Magnesium Nitrate, Zinc Sulphate solutions, and aerated distil water (hydropriming) for 24 hours at 15o C. Crops were subjected to three irrigation intervals in which the irrigation was applied at 0.9, 0.7, 0.5 Epan Replenishment of evaporation. Seed priming treatments reduced the mean emergence time, promoted germination, early canopy development and flower initiation in comparison to the untreated control. Plant height, number of branches, total dry matter accumulation, number of pods per plant, number of seeds per pod, 1000 seed weight and grain and biological yield, harvest index and irrigation water use efficiency  increased by different priming treatments. Seed priming increased the irrigation water use efficiency (IWUE) of all irrigation regimes. Grain yields linearly increased at 0.9 Epan Replenishment while maximum IWUE was achieved at 0.5 Epan Replenishment. Results suggest that the use of seed priming with either GA3 (100ppm) or Ammonium Molybdate (10-3 M) for 24 hours at low concentration can be helpful in cowpea under both optimum as well as limited water conditions.