J. Plant Breed. Genet. 02 (01) 2014. 01-05 1 Available Online at ESci Journals Journal of Plant Breeding and Genetics ISSN: 2305-297X (Online), 2308-121X (Print) http://www.escijournals.net/JPBG GENETIC STUDIES ON VARIATION FOR FIBER QUALITY TRAITS IN UPLAND COTTON Abdul Rasheed, Muhammad Rizwan, Jamshed I. Cheema, Shamsher H. Malik, Muhammad I.U. Haq, Shoaib Sohail Auriga Seed Corporation, 33-KM Multan Road, Lahore, Pakistan. A B S T R A C T Five cotton (Gossypium hirsutum L.) varieties namely SLH-41, F-281, COKER-3113, LA-85-52-1 and H-88-8-J.69-j.70 were studied in diallel cross experiment to evaluate genetic effects for various plant traits. The characters under consideration were Ginning out-turn, staple length, fiber fineness and strength All the genotypes were found to significantly differ from each other for the above mentioned traits. Joint regression analysis proved the validity of the data of all characters for additive-dominance model suggested by Hayman (1954) and Jinks (1954). Staple length, fiber fineness and fiber strength were controlled by additive gene action with partial dominance while Ginning out-turn revealed over dominance type of gene action. The predominance of additive gene action involved in the phenotypic manifestation of the traits suggested selection as an accurate procedure for character improvement. Keywords: Genetic studies, fiber traits, Upland cotton, Gossypium hirsutum L. INTRODUCTION Cotton occupies a unique position in Pakistanǯs agrarian economy. Efforts on various aspects of the crop have been under way to increase its overall production of the country. Pakistan is an agricultural country and cotton crop is the backbone for earning foreign exchange of the country.The economy of Pakistan mainly depends upon cotton production, exportable surplus of cotton fiber and fiber made products. Share of cotton and cotton manufactures is about 69% of the total foreign exchange annually. It accounts for 7.5% of the value added in agriculture and about 1.6% to GDP. It accounts for 78% of domestic oil production. The crop not only meets the need of the fiber of the local industry but also provides edible oil for cooking purpose and low grade oil for the soap manufacturing industries. Residual seed cake is a valuable protein concentrate that is used for livestock feed. (Anonymous, 2008). The most important factor in the process of crop production has always been a good variety in any crop. Cotton breeders managed to produce high yielding varieties through various genetic manipulations and breeding approaches and consequently a significant progress was achieved in this connection. As the improvement in yield and quality in agricultural crops is a continuous process, therefore, the breeders are busy all the time in adopting new techniques and approaches for improving the production of the crop. To achieve desirable results, parents utilize in any breeding program, must be genetically diverse and physiologically efficient. Keeping this in view, an experiment was undertaken in the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad to study the gene action in F1 hybrids to select suitable parents for the evaluation of high yielding hybrids, well adaptive to the prevailing climatic conditions and having better quality. The current research work was launched to analyze some important cotton cultivars to ascertain the relative performance regarding gene control for yield and its components. The diallel analysis technique devised by Hayman (1954) and Jinks (1954) which was reviewed and studied by Mather and Jinks (1982) is a useful tool to obtain precise information about the type of gene action involved for the expression of various yield characters. * Corresponding Author: Email ID: rasheedpbg@gmail.com © 2014 ESci Journals Publishing. All rights reserved.