Standardisation of Planting Ratio Staggered Sowing of Male Parent and Crossing Period for Pre Release Cotton Hybrids DHH 543 and DHB 290

Abstract

The field experiments were carried out for standardization of planting ratio, staggered newlinesowing of male parent and crossing period for pre-release cotton hybrids DHH-543 (Intra newlinehirsutum) and DHB-290 (Inter-specific) at Agricultural Research Station, Dharwad Farm, newlineDharwad during the kharif season 2001-02 and 2002-03. newlineIn order to get better synchronization of female and male parents with efficient newlineutilization of male flowers, the planting ratio of 2:1 in combination with staggered sowing of 10 newlineper cent male along with female, 30 per cent each at one, two and three weeks later than newlinefemale sowing was found to be optimum for DHH-543 hybrid seed production, as this newlineparticular staggered sowing in combination with 2:1 planting ratio recorded the seed yield of newline1221 kg per ha compared to either 3:2 (1260 kg) or 1:1 ratio (1269 kg), with higher boll weight newline(4.33 g), seed weight per boll (2.70 g), seed index (10.67 g) and seedling vigour index (2830). newlineSimilarly in DHB-290 hybrid seed production, the planting ratio of 2:1 with staggered newlinesowing of 25 per cent male seed one week before female, 25 per cent along with female and newline25 per cent each one and two weeks later than female sowing was found to be optimum. This newlinetreatment recorded higher hybrid seed yield (1450 kg/ha) compared to 3:2 (1434 kg/ha) or 1:1 newline(1438 kg/ha) planting ratio with higher boll weight (3.73 g), seed weight per boll (2.50 g), seed newlineindex (10.40 g) and seedling vigour index (2517). newlineSignificantly higher number of crossed flowers (42.0 and 31.3), crossed bolls (13.7 newlineand 11.8) and hybrid seed yield (26.5 and 32.2 g/plant and 216.3 and 437.8 kg/ha) were newlinerecorded at fourth and third fortnight compared to fifth fortnight crossing period, respectively newlineduring 2001-02 and 2002-03 in DHH-543 hybrid seed production. Similarly, in DHB-290 also newlinethe fourth and third fortnight compared to fifth fortnight crossing period recorded higher newlinenumber of crossed flowers (37.8 and 43.8), crossed bolls (12.2 and 13.8/plant) and hybrid newlineseed yield (22.1 and 34.2 g/plant, 180.3 and 465.6