Shashidhara, G. B.Tuppad, Giramallappa B.2020-02-192020-02-192015-11http://krishikosh.egranth.ac.in/handle/1/5810143255Field experiments were conducted under rainfed conditions at Main Agricultural Research Station, UAS, Dharwad during 2012-13 and 2013-14. One experiment consisted of three genotypes (RAH-274, SC-2028-22 and SC-7-58) as main plot, four spacings (45x10 cm, 45x15 cm, 60x10 cm and 60x15 cm) as sub plots and three fertilizer levels (80:40:40, 120:60:60 and 160:80:80kg N:P2O5:K2O/ha) under sub sub plots. Cotton genotype, RAH-274 recorded significantly higher seed cotton yield (2017 kg/ha) which was 7.5 per cent and 16.4 per cent higher over SC-2028-22 (1866 kg/ha) and SC-7-58 (1685 kg/ha), respectively. Spacing of 45x15 cm produced significantly higher seed cotton yield (2028 kg/ha) compared to rest of the spacings. Application of 160:80:80 produced significantly higher seed cotton yield (2063 kg/ha) compared to 120:60:60 kg N:P2O5:K2O/ha (1871 kg/ha) and 80:40:40 kg N:P2O5:K2O/ha (1635 kg/ha). Interaction of RAH-274 at spacing of 45x15 cm with higher level of fertilizer (160:80:80 kg N:P2O5:K2O/ha) recorded significantly higher seed cotton yield (2430 kg/ha), gross returns (.109233/ha), net returns (.75704/ha) and B:C (3.26) over other interactions. Another experiment during 2013-14 to study the effect of defoliator application on cotton genotypes under varied geometry. Application of Ethrel @ 2000 ppm recorded significantly higher seed cotton yield (2086 kg/ha) with an increase of 3.7 per cent and 8.8 per cent over Dropp Ultra @ 200 ml/ha (2009 kg/ha) and control (1902 kg/ha), respectively. The significantly higher leaf defoliation was recorded with Ethrel @ 2000 ppm (83.2 %) than Dropp Ultra @ 200 ml/ha (76.2 %) and control (45.3 %) with significantly lower number of leaves (1.2 leaves/plant) and leaf area (3.01 dm2/plant) at 18 days after defoliator spray. The fibre quality parameters were influenced by genotypes and values were within specified range. Interaction of RAH-274 at spacing of 45x15 cm with application of Ethrel @ 2000 ppm recorded significantly higher seed cotton yield (2241 kg/ha), boll opening (99.3 %), gross returns (1,00,830/ha), net returns (67,910/ha) and benefit cost ratio (3.06) over rest of interactions.ennullThesis