Relative peformance of new plant type lines during the dry and wet seasons
2000
Visperas, R.M. | Peng, S. | Khush, G.S. | Pamplona, A. (International Rice Research Inst., MCPO Box 3127, 1271 Makati City (Philippines))
This study was conducted to verify whether the relative performance of new plant type (NPT) lines is better in the wet season (WS) than in the dry season (DS) and to identify NPT lines with good grain filling capacity and larger panicle size. Fifty-two and 58 NPT lines were grown in the DS and WS of 1999, respectively. The check cultivars used were indica inbreds PSBRc52 in DS and IR72 in WS. Twenty-one-day old seedlings were transplanted at a 0.10 x 0.15 m hill spacing with one seedling per hill in both seasons. Input of fertilizer N was 120 kg/ha. At maturity, samples were taken from a 0.5 sq m area to determine panicle number, spikelets per panicle, grain filling percentage, and 1000-grain weight. Grain yield was determined from a 5 sq m area. During the DS, four NPT lines had yields equal to or greater than PSBRc 52. IR70479-45-2-3 produced the highest yield of 7.4 t/ha, about 10% higher than that of PSBRc52. During the WS, 49 NPT lines produced yields the same as or greater than IR72. IR68552-55-3-2 produced the highest yield of 6.5 t/ha, about 50% higher than that of IR72. These results suggest that the relative performance of NPT lines in WS is better than in DS. The possible reasons for this are their being panicle-weight type, better lodging resistance, better canopy structure for light interception, and better shade tolerance in terms of single-leaf photosynthetic rate than the indica inbreds
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