Comparative Laboratory Studies of Cowpea (Vigna Unguiculata) and Soya bean (Glycine Max) Under Tropical Temperature Conditions

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Ndunguru, B.G.
Summerfield, R.J.
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The effects of seed size (large and small), with and without seed dressing ("Arasan") and four high temperatures (29°, 33°, 39° and 43 0c) on the germination and hypocotyl elongation of cowpea cv. K2809 and soyabean cv. Grant were investigated. Seed ,size had no effect on the rate of germination of cowpea whereas small soyabean seeds had a lower percentage germination than large ones, but ,as for cowpea, produced longer hypoootyis. Seed dressing had no signifioant effect on the germination .of cowpea ,seeds but the percentage germination of small 'soyabean seeds improved when they were treated with "Arasan". Soyabean ,seeds germinated most rapidly between 29°C and 33°C but not at all at 43°C. Some cowpea seeds (60 per cent), however, germinated even at 43°C and 100 per cent germination was obtained at all other temperatures. The optimum temperature for hypocotyl elongation of ,soyabean was 33°C; some reduction occurred at 29°C and growth of the hypocoty18 was severely restricted at 39°C, With cowpea, no hypocotyl elongation followed germination 'at 43°C and elongation was restricted at 39°C also. The implications of these findings in relat~on to stand establishment of both legumes in ~he !tropics is discussed.
East African Agricultural and Forestry Journal, 41 (1), pp. 58-64