Studies on heterosis for yield, yield contributing and fibre quality traits in Bt (BG II) cotton (Gossypium hirsutum L.)

The present investigation, entitled “Studies on heterosis for yield, yield contributing and fibre quality traits in Bt (BG II) cotton (Gossypium hirsutum L.)”, was carried out during the 2024-2025 kharif season at the Cotton Research Station, Nanded, under Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani. The objective was to assess heterosis for important agronomic and fibre quality traits using a Line × Tester mating design. The experimental material included five female (line) genotypes and four male (tester) genotypes, resulting in 20 hybrids. Three commercial Bt checks viz., Suraj Bt (variety), NHH 44 BG II, and Jadoo BG II (hybrids) were used for comparison. All 32 entries were evaluated in a Randomized Block Design with two replications. Data were recorded on 14 traits, namely days to 50% flowering, days to maturity, plant height, number of sympodia and bolls per plant, boll weight, seed cotton yield, seed index, lint index, ginning outturn, upper half mean length (UHML), micronaire, fibre strength and uniformity ratio. Analysis of variance revealed significant differences among genotypes for all traits, indicating considerable genetic variability. Hybrids NH 22097 Bt × AC 738 Bt and NH 22057 Bt × AC 738 Bt recorded the highest seed cotton yield. Notably, NH 22097 Bt × AC 738 Bt showed the highest heterosis for seed cotton yield, with 118.86% BPH, 81.08% over NHH 44 BG II, 71.20% over Jadoo BG II, and 93.06% over Suraj Bt. for UHML, NH 22097 Bt × NH 22075 Bt and NH 22057 Bt × NH 22037 Bt were the best performers. These results highlight the potential of specific hybrids for yield and fibre improvement in Bt cotton.