Composite-crossing methodology pays rich dividend in cotton breeding-a resume

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 combining lines for yield, bolls/plant, bollweight, lintout-turn,superior fibre quality from 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-bollworm, aphid and jassid resistant irrigated cotton JK 119)combining desirable traits. The varieties have given significant jump in yield (70–100% over checks), shortened crop duration (150–155 days, checks 200–210 days), high boll weight (10.6 g, check 3.8 g) high lint per cent (39–42%, 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 23-18-7 have produced 15–24% higher yield than DCH-32 hybrid cotton with matching fibre quality.