COMPOSITE-CROSSING METHODOLOGY PAYS RICH DIVIDEND IN COTTON BREEDING-A RESUME

Abstract

The paper summarises results of two decades (1969-1988) of successful cotton breeding (Gossypium hirsutum L. and G. barbadense L.) done by the author, using the composite breeding methodology. The elements of technology include: identifying high general combininglines for yield, bolls/plant, boll weight, lint out-tum, superior fibre qualityfrom top-cross testing, using a double cross varietal hybrid as the pollen source, crossing the selected lines in numerous combination, composite-crossing between the resultant hybrids bymixing pollen from all the hybrids, raising extensive progenies (20,000 plants) from such composite crosses, selecting superior recombinant segregates and mating them again through composite-crossing over 3-4 cycles, followed by 2 to 7 cycles of inter se mating within the family. The results were highly gratifying. Numerous high yielding lines were developed and a few released for commercial cultivation (e.g. JK 97, Sharada-multiple pest-resistant rainfed cotton; Abadhita-bollwonn. aphid and jassid resistant irrigated cottonJK119)combiningdesirable traits.The varieties have givensignificant jumpin yield (70-100% over checks), shortened crop duration (lSO-15~days, checks 200-210 days), high boll weight (10.6 g, check 3.8 g) high lint per cent (39-420/., check 34.5%) multiple pest-resistance (resistant to jassids, aphids, bollworms, stem weevil, red spider and whitefly) wide adaptability across agroclimatic zones of India. Single stem, short-branch lines maturing in 130-135 days, suitable for high density planting and machine picking giving 106% higher yield and 45-47% lint out-tum are undergoing multilocation testing across the Nation. The G. barbadense variety DCS 23-18-7 giving 70-100% higher yield over the check. Suvin, shorterin maturity and having excellent fibre quality, is undergoing final testing before release. Varieties JK-119 and DCS 23-18-7have produced15-24% higheryield than DCH-32 hybrid cotton with matching fibre quality.