Abstract
Gene action was studied for ginning outturn percentage, staple length and fibre fineness in a diallel cross of six cotton cultivars viz. Allcpo-45, Okara, Cocker 5110/111, Brace 81/6, SPA/66 and 272/79. Additive type of gene action was ob-served in the inheritance pattern of all the characters mentioned above.
INTRODUCTION MATERIALS AND METHODS
Our textile industry consumes 4 million bales of locally produced cotton, Pakistan at present is producing 8.25 million bales which is over and above its needs (Anonymous, 1989), The surplus is exported. Over production does not mean to stop the process of our varietal improvement for their yield and quality. Apart from increas-ing the yield potential of our prevailing germ plasm it is now imperative to improve its quality traits. The fibre traits such as staple length, fibre fineness, strength and maturity go a long way in determining the demand of a cotton variety in the textile industry (Afzal and Khan, 1%1). Such improvements can be imparted in our varieties through breeding, but some prior necessary genetic informations about the characters to be improved are needed (gururaja Rao, 1975). The present studies were therefore, initiated for investigating the gene action controlling some of the characters of the above mentioned importance.
The experiment was conducted in the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad during the year 1985-86. The experimental material consisted of six cultivars of cotton (Go$soitim hirstiturn L.) including one local (272/79) and five exotic viz, Allepo-45, Okara, Coker 51.10/111, Brace 81/6 and BPA/6. The material fulfilled the assumptions of diallel analysis. The homozygosity of the cultivars was maintained by the researchers in the department for three years. It was as-sumed that inheritance of the characters would be Mendelian and diploid, and that the genes would be independently dis-tributed in the parents. No multiple allelisni and reciprocal differences could be there. These varieties were grown in 30 x 30 cm earthen pots during November 1985 placed in the greenhouse. The temperature within the greenhouse was maintained be-tween 60 °C to 100 ° C throughout the growing period. At flowering these varieties were crossed in all possible combinations to have a complete diallel set of crosses.
