Electronic Journal of Plant Breeding, 8(2): 615-619 (June 2017) ISSN 0975-928X http://ejplantbreeding.com 615 DOI: 10.5958/0975-928X.2017.00093.X Research Note Estimation of heterosis for seed cotton yield and biochemical parameters in genetic male sterile based hybrids of Gossypium arboreum L. R.D. Vekariya * , S. Nimbal, R.S. Sangwan, S. Mandhania, O. Sangwan and S.R. Pundir Department of Genetics and Plant Breeding, Cotton Section, Chaudhary Charan Singh Haryana Agricultural University, Hisar-125004 E-mail: rajesh22vk@gmail.com (Received: 12 Dec 2015; Revised: 19 Jan 2017; Accepted: 30 Jan 2017) Abstract The present investigation was undertaken to study heterosis and explore its commercial utilization in desi cotton (G. arboreum L.) by using Line x Tester design with four genetic male sterile females and fifteen male parents. Out of sixty hybrids studied, a total thirty three hybrids showed positive heterobeltiosis and seventeen hybrids showed positive economic heterosis over standard check, AAH 1 and thirty nine crosses showed positive mid parent heterosis for seed cotton yield. The F 1 hybrids DGMS 34 x HD 517 (53.19 %), DGMS 34 x HD 523 (40.00 %), DGMS 2 x HD 528 (39.96 %) and DGMS 1 x HD 432 (39.97 %) recorded positive standard heterosis for number of bolls, seed cotton yield and low gossypol content, while the maximum heterobeltiosis for seed cotton yield per plant was exhibited by the hybrid DGMS 2 x HD 528 (121.82 %) followed by DGMS 1 x HD 432 (114.48 %) and DGMS 1 x CNA 398 (84.62 %). Hybrid DGMS 34 x HD 517 had reduced level of gossypol and DGMS 1 x LD 1026 had high level of protein while DGMS 9 x CNA 398 had high level of oil content over standard check AAH 1. Key words Gossypium arboreum L., Heterosis, Line x Tester analysis, Genetic Male Sterility Gossypium arboreum, (diploid cotton) is very well adapted to the fluctuating environmental conditions and is still under cultivation because of its inherent ability to resist major pests and diseases. As the world's foremost natural fibre crop, cotton supports a multibillion dollar production and processing industry. Cotton is widely cultivated worldwide for its natural fiber, but the byproduct of cotton processing industry is also important. Like cotton seed is an important source of vegetable oil and high protein meal. Cotton seed contains 18-20% seed oil which is edible after removal of gossypol by hydrogenation (Narayanan et al., 1975) and 17- 23 per cent seed protein meal. The cost of hybrid seed production at a commercial scale is cheaper in cotton due to naked floral biology, more number of seeds per cross, higher rate of seed setting and higher percentage of successful crosses. Genetic male sterility adds to the advantages. These important characteristics offer opportunity to crop improvement and development of new crop variety through hybridization. The extent of heterosis acts as a basic tool for the choice of desirable parents for developing superior F 1 hybrids to exploit hybrid vigour and for building new gene pools to be employed in further breeding programmes. Exploitation of heterosis on commercial scale and systematic varietal improvement through hybridization are the main tools to increase cotton production. For the success of cotton breeding programme, there is a basic need in selecting proper parents for hybridization. Keeping in view the above points, the present investigation was carried out with the objectives to know the extent the heterosis for seed cotton yield and biochemical parameters in G. arboreum L. . The material for the present investigation comprised of 80 G. arboreum L. cotton genotypes viz., 60 hybrids developed on 4 Genetic Male Sterile (GMS) female parents (lines) and 15 male parents (testers) in Line x Tester mating design along with their parents and one standard check (AAH 1). Table 1 explains male and female parent characteristics used in the experiment. The crosses were made during kharif 2014 in Line x Tester mating design at the Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar and the experimental material was grown during kharif 2015 in a randomized block design with three replications. They were sown in two rows of 6.0 m length with spacing of 67.5 cm between rows and 60 cm between the plants. Economic heterosis was calculated as per method suggested by Turner (1953) for seed cotton and other traits as the deviation of F 1 values over the check variety (AAH 1) for each trait and expressed in percentage. The per cent increase or decrease of F 1 over the mid parent is referred as average heterosis, while heterobeltiosis denotes the per cent increase or decrease of F 1 over the better parent and is estimated as per method given by Fonseca and Peterson (1968). All the recommended cultural package of practices and need based plant protection measures were followed from sowing till harvesting the crop. Thirteen characters including seed cotton yield and its related traits and biochemical parameters were studied. Five plants randomly selected were tagged