IMPROVEMENT IN FIBER-BUNDLE STRENGTH IN MEDIUM-STAPLE VARIETIES OF UPLAND COTTON (GOSSYPIUM-HIRSUTUM)

Improvement of fibre-bundle strength in 6 strains of 'Pusa 2' upland c otton (Gossypiwn hirsutum L.) was made with the help of pedigree selec tion during 1989-91 at New Delhi. Total 40 progenies in 1990 and 18 pr omising progenies in 1991 were evaluated for seed-cotton yield and fib re-quality traits like length, uniformity, fineness, maturity, bundle- strength tenacity and count-strength product at 60 counts. 'Pusa 2-98' (2 101 kg/ha), 'Pusa 2-103' (2 052 kg/ha) and 'Pusa 2-123' (2 066 kg/ ha) were superior to the control 'H 777' (1 905 kg/ha) in seed-cotton yield. In overall mean 'Pusa 2-95' proved superior in fibre fineness ( micronaire value 4.2), fibre-bundle-strength tenacity at 3.2 mm gauge (34.3) and count-strength-product value st 60s count (2 582) compared with fineness of 4.5, bundle strength at 3.2 mm gauge (27.6) and count -strength-product value (1 860 at 40s count) of the control. Pedigree method led to selection of superior progenies (giving better than mean values) were isolated in 199 1. From 'Pusa 2-95', 2 progenies ('20' a nd '35') with fibre-bundle-strength tenacity at 3.2 mm gauge of 36.0 a nd 36.2 g/tex were found promising. 'Pusa 2-95-32' with fibre-bundle s trength 34.5 g/tex was better in lint yield (603.5 kg/ha) among the pr ogenies of 'Pusa 2-95'. 'Pusa 2-98-20' (33.5 g/tex) and 'Pusa 2-103-4' (32.2 g/tex) were high-yielding strains (677.0, 750.5 kg lint/ha) but with coarse fibre (4.5 micronaire value). As a result of 2 cycles of selection, fibre-bundle strength in 'Pusa 2-95' improved by 12.8% (31. 9-36.2 g/tex), in 'Pusa 2-54' by 11.9% (29.2-32.7 g/tex), in 'Pusa 2-9 8' by 23.2% (27.2-33.5 g/tex), in 'Pusa 2-103' by 6.6% and in 'Pusa 2- 116' by 13.4%.