Genetic studies on grain yield= and yield components in rice (Oryza sativa= L.) under aerobic condition

M.P.Rajanna, K.B.Kemparaju, B.Vidyachandr= a and M. Syed Anwarulla

AICRP(Rice), Zonal Agricultur= al Research Station, University of Agricultural Sciences, V.C.Farm, Mandya= , , Karnataka

Forty eight diverse rice genotypes were grown under aerobic condition at Zonal Agricultural Research Station, V.C.Farm, Mandya and studied the genotypic coefficient of varia= tion (GCV), phenotypic coefficient of variation (PCV), heritability (h^{2)
and genetic advance (Gs) for 12 yield and yield component characters viz., days to 50% flowering, plant
height, leaves per hill, productive tillers per hill, panicle length, spikelet fertility, grain number per panicle, test we=
ight,
grain yield per hill, harvest index, carbon isotope discrimination (∆=
¹³
C) and leaf area duration (LAD).}

Phenotypic co-efficient of variability was found to be more than the genotypic co-efficient of variability for most of the characters. The PCV and GCV val= ues were of higher magnitude for the LAD, leaves per hill, productive tillers p= er hill and grain number per panicle. While, both the values were low for pani= cle length and ∆ 13 C. Grain yield per hill exhibited low GCV and high PCV.

Heritability was very high for days= to 50 per cent flowering, grain number per panicle, panicle length, plant height,= spikelet fertility, test weight, productive tillers p= er hill, leaves per hill and ∆¹³C. The LAD showed moderate heritability estimates. While low heritability estimates were observed for grain yield per hill and harvest index.&nb= sp; The genetic advance was very high for days to 50 per cent flowering, grain number per panicle, plant height and leaves per hill but it was moder= ate for spikelet fertility. whereas, harvest index and grain y= ield per hill exhibited lowest genetic advance.

Estimates of genetic advance and heritability values for different morpho-physiological traits indicated the operation of both additive and non additive gene action for days to 50% flowering, plant height, panicle length, spikelet fertility, test weight, productive tillers per hill, leaves per hill, ͧ= 0; ¹³ C and LAD. While, it was only additive gene action for grain number per panicle. Non-additive gene action was evident for grain yield and harvest index.

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