Effect of paraquat and ethephon to accelerate harvest and drying method on seed quality of soybean

Sawat Harnprab; Thirasak Pratheep Na Thalang; Wanchai ChanprasertKasetsart Univ., Bangkok . Faculty of Agriculture. Dept. of Agronomy

Effect of paraquat and ethephon to accelerate harvest and drying method on seed quality of soybean

1997

Sawat Harnprab | Thirasak Pratheep Na Thalang | Wanchai ChanprasertKasetsart Univ., Bangkok (Thailand). Faculty of Agriculture. Dept. of Agronomy)

Studies on the use of paraquat and ethephon at physiological maturity to accelerate harvesting and the effect of drying methods on seed quality were carried out with 2 soybean cultivars namely Chiang Mai 60 and SJ.5 grown in rainy season (April 1997) on farmer's field at Thumbon Ponangdumtok, Amphur Sabpaya, Chainat Province. Three drying methods, i.e. bin drier at 39 deg C, blower at room temperature and sun drying were used to dry the early harvested soybean plants. The results showed that for both varieties paraquat application caused higher rate of defoliation and reduced seed moisture content lower than ethephon and non-treated control. Paraquat and ethephon did not affect soybean seed germination. For drying methods with early harvested soybeans, results revealed that drying by bin drier at 39 deg C consumed shortest time for seed to reduce moisture content to the required level comparing to sun drying and blowing at room temperature. After drying, seed quality was rather low in Chiangmai 60 variety with seed germination lower than 65 percent. However soybean SJ.5 variety gave high seed quality with 81 percent seed germination. In SJ.5 soybean, paraquat application followed by drying with blower at room temperature gave the best result in terms of management for soybean with chemical accelerated harvesting. This combination gave high seed quality which was measured by standard germination, accelerated ageing, electrical conductivity test and field emergence test and the seed could be stored upto 4 months with the standard germination higher than 70 percent.

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