Effect of seed priming and rate on direct-seeded,. rainfed summer rice (Oryza sativa)

Abstract

Rainfed summer rice (Oryza sativa L.) panicle number and filled grainslpanicle, suffers from frequent drought conditions, re-. and better N, P and K uptake and water-use sulting in very low and fluctuating yield. efficiency, thereby giving significantly Seed priming induces drought tolerance to higher yield than the other treatments the crop. In view of this, a field experiment (Tables 1, 2). Similar observations were was conducted to study the effect of potas- made by Peeran and Natanasabapathy sium as priming material on the plant- (1 980) and Borgohain (1988). However, water-relationship and ultimately on yield of grain yield was significantly higher when direct-seeded summer rice and also to find the seed rate was 70 kglha. The lower was out an optimum seeding rate of primed seed. the seed rate the higher was the number of The study was carried out at Jorhat during grainslpanicle, 1,000-grain weight and wa- summer 1989 in a randomized block design. ter-use efficiency (Table 1). Interaction of The soil was sandy loam with pH 5.25 (1 : seed priming and seed rate on grain yield 2), organic carbon 0.935% and available N, 2720, 0.25 and 1556 kfla re- TaM 1. Grain yield (@a) of IR 50 rice as affected 4 spectively. the interaction between seed priming and seed The treatments consisted of- seed priming . rate with KC1 solution @ 0,3,4,5 and 6% along - with the normal practice of dry seeding and Seed Seed rate (kglha) 3 seed rates of IR 50 (70, 85 and 100 kg/ priming ha). The seeds were air-dried under shade 7O 85 100 Mean after priming to bring the moisture content Dry seeding 7.82 9.09 9.25 8.72 to normal before sowing. The seeds were 0% 10.81 8.49 8.44 9.25 sown in lines 25 cm apart on 25 March 1989 3% 11.08 10.67 10.35 10.70 and the crop matured in 118 days. Fertiliz- 4% 13.75 11.58 11.36 12.23 ers were applied @ 40, 20 and 20 kg N, 5% 12.75 11.40 11.13 11.76 P20, and K20ha respectively. The con- 6% 12.03 9.97 10.95 10.98 sumptive use of water in the crop was esti- Mean 11.37 10.20 10.24 mated by using the soil-m~isture~depletion method and the water-use efficiency by di- = CD (P 0.05) viding the grain yield with consumptive use. Seed priming 0.46 Seed priming with 4% KC1 resulted in Seed rate 0.33 the significantly highest plant population, !nteraction 0.80