HETEROSIS AND GENE ACTION STUDIES IN BT COTTON (BG I) (GOSSYPIUM HIRSUTUM L.)

Heterosis and combining ability analysis is one of the most prominent and conventional tools for improvement in Cotton (Gossypium spp.).In this context an experiment was conducted in Kharif 2023-24 using five lines, four tester and two checks in Randomized Block Design (RBD) at Cotton Research Station, Nanded, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani.Objectives of this research were to assess heterobeltiosis, useful and standard heterosis and to identify superior parents and cross combinations based on their combining ability.In addition, assessment of sucking pest tolerance was also carried out using simple correlation studies.Fourteen observations were recorded based on yield and yield contributing traits viz.Days to 50% flowering, days to maturity, plant height, number of sympodia per plant, number of bolls per plant, boll weight, seed cotton yield, seed index, lint index, fibre quality traits viz.ginning outturn, upper half mean length, micronaire value, fibre strength and uniformity ratio.Crosses NH 22340 Bt x NH 22308 Bt, NH 22482 Bt x NH 22384 Bt, NH 22482 Bt x NH 22308 Bt and NH 22279 Bt x NH 22254 Bt exhibited highest heterobeltiosis, heterosis over standard check variety and standard check hybrid for traits viz.number of sympodia per plant, number of bolls per plant, boll weight and seed cotton yield.Crosses NH 22340 Bt x NH 22384 Bt, NH 22482 Bt x NH 22308 Bt, NH 22482 Bt x NH 22254 Bt, NH 22340 Bt x NH 22294 Bt and NH 22316 Bt x NH 22308 Bt reported highest heterobeltiosis, heterosis over standard check variety and over standard hybrid for given fibre quality traits such as UHML, micronaire value, fibre strength and uniformity ratio.Among the parents, NH 22257 Bt, NH 22279 Bt, NH 22340 Bt, NH 22384 Bt and NH 22308 Bt proved to be good general combiners for yield, yield contributing and fibre quality traits.Crosses NH 22279 Bt x NH 22254 Bt, NH 22316 Bt x NH 22384 Bt, NH 22340 Bt x NH 22384 Bt, NH 22279 Bt x NH 22308 Bt and NH 22257 Bt x NH 22384 Bt displayed high estimates of SCA effects for different traits.Experiment showed that there was predominance of non-additive variance for all characters suggesting of heterosis breeding in future.