Genotype - environment interaction in new plant type (npt) lines of rice (oryxa sativa L)

Abstract

The present study on Genotype - Environment interaction in New Plant Type (NPT) lines of rice was carried out in the Department of Plant Breeding & Genetics, College of Horticulture, Kerala Agricultural University, Vellanikkara. Eight selected NPT rice lines (developed at IRRI) along with Jyothi as check variety were evaluated for ten agronomic characteristics and seven grain quality characteristics across three low land rice ecosystem in Palghat district in central zone of Kerala during rabi season 2005. In the experiment, variability, heritability, genetic advance, correlation, path analysis and stability were disclosed. Mean performance of NPT rice lines across three locations revealed that in general NPT rice lines performed significantly better than check variety at two locations for grain yield. Characters like days to 50 per cent flowering and number of productive tillers and harvest index did not differ significantly than that of Jyothi at all the test locations. With respect to grain quality parameters such as L/B ratio, 1000-grain weight, milling percentage and head rice recovery. NPT-8 had shown better grain qualities except amylose content.Jyothi showed superior performance for this character. In general, panicle length and mean number of spikelets were high in most of NPT rice lines than Jyothi.The average plant height of NPT lines was same or higher than that of Jyothi.None of the NPT rice lines showed tendency to lodge. Grain yield was positively and significantly correlated with days to 50 per cent flowering, number of spikelets per panicle, panicle length and straw yield .Path analysis indicated that characters like days to maturity, number of spikelets per panicle, straw yield and 1000-grain weight had the positive direct effect on grain yield. Based on the economical important agronomic characters, promising NPT rice lines for each location were identified. At Nenemni, the promising NPT lines identified were NPT-2, NPT-3 and NPT-4.Taking into consideration of grain quality parameters like medium shaped grains, high 1000-grain weight and head rice recovery, NPT-8 was adjudged as a best NPT line at Nenmeni.NPT-2, NPT-5, NPT6 and NPT-8 were identified as the promising four NPT rice lines at Thenkurissi. At Mathur, NPT-4, NPT-7 and NPT-8 were identified as the promising NPT rice lines. Based on the performance for yield, agronomic characters, grain characteristics and stability NPT-7 had shown better performance in the present study.