Hybrid vigour and inbreeding depression for fibre quality in upland cotton (Gossypium hirsutum L.).

摘要

In upland cotton (Gossypium hirsutum L.), 45 cross hybrids were produced by using 10x10 half diallel fashion and were evaluated along with their 45 F₂'s and 10 parents in R.B.D. replicated thrice. The magnitude of heterosis over mid parent and better parent, as well as inbreeding depression, were calculated for various fibre quality traits. Twenty seven crosses showed significant positive heterobeltiosis for seed cotton yield/plant. Based on the present study eight crosses viz., F 1867 x LH 1836, F 1867 x H 1123, F 1861 x C 2602-WIR 6109, F 1861 x LH 1836, C 2602-WIR 6109 x Pusa 101, PIL 8-5 x H 1123, LH 1836 x RS 2115, and H 1123 x RS 2115 were considered most promising for seed cotton yield/plant and most of the other fibre quality characters. The highest significant negative inbreeding depression were showed in crosses namely; C 2602-WIR 6109 x LH 1836 for ginning per cent; F 1861 x RS 2115 for lint index; F 1861 x LH 1896 for 2.5 per cent span length; C 2602-WIR-6109 x LH 1836 for fibre fineness; C 2602-WIR 6109 x Pusa 101 for seed index; and LH 1861 x H 1123 for seed cotton yield/plant. Significant negative inbreeding depression was recorded for yield and fibre quality traits indicating that the F₂ was superior to the F₁. The study showed the potential of commercial exploitation of heterosis through the production of hybrid cotton, as well as the potential of isolating the pure lines among the progenies of heterotic F1s for improvement of yield as well as fibre quality potential in upland cotton.