Back to Contents

FREE FULL TEXT PDF

STABILITY OF COTTON CULTIVARS FOR EARLY CROP MATURITY ACROSS VARIABLE PLANT SPACING AND SOWING TIMES

M. KAUSAR NAWAZ SHAH*, SAEED A. MALIK**, MUHAMMAD SALEEM

Abstract: Earliness of crop maturity being a complex trait in cotton is significantly altered by a number of agronomic practices including inter plant spacing and sowing time thus making identification of true early maturing cultivars a difficult task under field conditions. In this study, cotton cultivars were subjected to twelve environments provided through three plant spacings, two sowing dates over two years to assess phenotypic stability for earliness index. The stability parameters were calculated following Eberhart & Russell. Stability analysis revealed presence of genetic differences among cultivars for earliness index. Significant cultivar X environment (linear) indicated differential response of cultivars to various environments for earliness index. Cotton cultivars 15/2S and Krishna showing near unity (<1.0) regression coefficient (b) were regarded as above average stable which can mature early under all environments. CIM-448, despite showing higher mean value, had b value significantly distant from unity, hence regarded as unstable for earliness over variable growing conditions. CIM-448, under May sowing and CIM-1100 under June sowing, can be utilized as substitutes in the absence of true early maturing cultivars. Cultivars Krishna and 15/2S were found to be stable for earliness of crop maturity over a range of environments and can safely be utilized as early maturing parents in any cotton crop maturity improvement programme.
 

Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad, Pakistan.
Cytogeneticist, Barani Agricultural Research Institute, Chakwal.
Professor of Botany, Institute of Pure and Applied Biology, Bahauddin Zakariya, University, Multan.