Effect of planting over-aged seedlings on rice duration, yield and yield attributes [India]
1988
Sreekumar, S.G. | Nair, V.G. | Asan, R.B. (College of Agriculture, Vellayani, Trivandrum, Kerala (India). Plant Breeding Dept.)
Varietal differences in growth duration are due primarily to differences in length of the vegetative phase. Fifteen prerelease cultures and varieties in the 1983 wet season were studied. The field experiment was conducted in a randomized block design with three replications. Due to an unprecedented severe drought, 54-d-old seedlings were transplanted to 2-3 seedlings/hill spaced 15x15 cm. The maturity of short-duration varieties (95-120d) was prolonged to 108-134 d, primarily because of delayed flowering. The maturity of medium duration varieties (125 to 140 d) was not extended. Extended duration differed among varieties. The differences in maturity in short-duration varieties could not be associated with their expected duration. Duration of 113-d Cul. 1954 was extended by 9d, that of 108-d Cul. 25337 by 26d. The capacity to extend the growth period and thereby the duration, could be a varietal character independent of actual duration. Grain yield was independent of duration. Cul. 4 M0.5, Karthika, and Jyothi had high yields; Cul. 126, Cul. 43-1-4, Cul. 25331, Bhagya, and Onam low yields. Panicles per hill and 1000-grain weight showed a similar trend. The drought stress experienced in the nursery might have persisted after transplanting in some varieties, while other varieties recovered during subsequent growth. Varieties capable of adjusting could be recommended for conditions when a delay in transplanting can be anticipated.
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