INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY ISSN Print: 1560–8530; ISSN Online: 1814–9596 07–040/AWB/2008/10–4–447–450 http://www.fspublishers.org Full Length Article To cite this paper: Naeem, M. and F.M. Azhar, 2008. Identification of superior parents and hybrids for yield and its components in cotton (Gossypium hirsutum). Int. J. Agri. Biol., 10: 447–50 Identification of Superior Parents and Hybrids for Yield and its Components in Cotton (Gossypium hirsutum) MUHAMMAD NAEEM 1 AND FAQIR MUHAMMAD AZHAR Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad-38040, Pakistan 1 Corresponding author’s e-mail: mnbzu@hotmail.com ABSTRACT The purpose of this study was to identify superior parental combinations based upon general and specific combining abilities in order to exploit their potential for increasing seed cotton yield. Five cotton lines ( NIAB 111, NIAB 999, CIM 448, MNH 93 & FH 901) and three testers (LRA Blight, CP 15/21 & 289 F-1) were crossed according to line × tester mating system. Data on 23 genotypes were recorded on monopodial and sympodial branches, number of bolls, boll weight, seed index and seed cotton yield. The variation due to general combining ability of the parents and specific combining ability of the hybrids for plant yield and its components were estimated by line × tester analysis. Result showed that MNH 93 was the best combiner for most of the traits studied. Variance components analysis indicated that except boll weight, all other characters were predominantly influenced by dominance properties of genes. Three varietal combinations NIAB 999 × CP 15/21, CIM 448 × LRA Blight and MNH 93 × 289 F-1 expressed high specific combining abilities for all characters. Results suggest that the parents may be used in the hybridization program aiming to develop hybrid cotton. Key Words: Gossypium hirsutum; Combining ability; Line × tester analysis INTRODUCTION Eextensive efforts were made by the breeders to exploit its potential for increasing cotton production due to the immense role of cotton crop in the economy of Pakistan. As a result, a galaxy of high yielding varieties with better quality characteristics were evolved for general cultivation in varying ecological zones of the cotton belt of the country. Due to wider adaptability of the recently bred varieties total production of the country increased considerably and during the crop year 2005 Pakistan had achieved the record production of 14.618 million bales (Anonymous, 2005). In order to meet the increasing demand for raw fibre in the local textile industry and for earning more foreign exchange through exportable surplus, the efforts must be made to keep pace, with the increasing demand of fibre and oil. Cotton improvement program may be more effective if information on the genetic mechanism controlling economic characters are available to the breeders. In addition, in order to develop promising plant material through hybridization, availability of superior parents is essential. The estimates of general combining ability are important to determine the value of genotypes in hybrid combinations. Further differences in general combining abilities of varieties/lines were attributed to additive, additive × additive and higher-order additive interactions, whereas differences in specific combining ability were attributed to non-additive genetic variance (Falconer & Mackey, 1996). One of the biometric methods used to collect such information is line × tester analysis. This mating design provides information about the general and specific combining abilities of the parents and also genetic basis of variation in different plant characters. Therefore, in order to gather such information about the germplasm available the present study was undertaken on eight varieties of cotton (Gossypium hirsutum L.). MATERIALS AND METHODS The material for the present studies comprised five female parents (lines) namely, NIAB 111, NIAB 999, CIM 448, MNH 93 and FH 901 and three male parents (testers), LRA Blight, CP 15/21 and 289 F-1. These eight parents were grown in 30 × 30 cm earthen pots in a green house. The temperature in glass house was maintained between 21 o C (night) and 37 o C (day) using steam as well as electric haters. The seed parents (lines) were hand emasculated in evening and pollinated with testers the following morning to produce enough F1 hybrid seed. Extreme precautionary measures were taken to avoid pollen contamination of the genetic material during selfing and crossing operations. Seeds of 15 F1 hybrids along with their selfed parents were field planted during the crop season 2005 with 75 cm row-to-row and 30 cm plant-to-plant distance and there were ten plants in each row. Experimental design was randomized complete block design with three replications. At maturity