RESPONSE OF GROUNDNUT GENOTYPES TO PHOTOSYNTHETICALLY ACTIVE RADIATION

The causes of high yield potential of groundnut (Arachis hypogaea L.) genotype Rebut 33-1 in comparison to GG-2 (the released variety) durin g summer season were assessed under experimentally created varying env ironments using meteorological parameters. The genotype Robut 33-1 had higher PAR conversion use efficiency (CUE) than GG-2 at all the growt h stages studied. The relation between PAR absorption coefficient (Y) and days after sowing (D) for Rebut 33-1 was : Y = -0.647 + 0.018 D - 0.000057 D-2 and for GG-2 it was: Y = -1.016 + 0.029683 D - 0.000125 D -2, with R(2) > 0.86. The rate of dry matter production was linear ove r the intercepted PAR (R(2) > 0.88). The CUE (dry matter produced per unit of intercepted PAR), by linear regression technique was 1.542 g M J(-1) in Robut 33-1 and 1.067 g MJ(-1) in GG-2. The results revealed t hat PAR and CUE could be utilized in selection programme for high yiel d potential.