PJB-2011-205
COMBINING ABILITY ANALYSIS IN INTRASPECIFIC F1 DIALLEL CROSS OF UPLAND COTTON
SHERAZ AHMED KHAN1*, NAQIB ULLAH KHAN1, FIDA MOHAMMAD1, MUSHTAQ AHMAD1, IJAZ AHMED KHAN2, ZARINA BIBI3 AND IMDAD ULLAH KHAN3
Abstract
The research work comprised of combining ability and genetic variability in a 6 × 6 F1 diallel cross which was carried out during crop seasons 2008 and 2009 at Khyber Pakhtunkhwa Agricultural University, Peshawar, Pakistan. The parental genotypes (CIM-446, CIM-496, CIM-499, CIM-506, CIM-554 and CIM-707) were crossed in a complete diallel fashion during 2008. The 30 F1 hybrids and their parents were grown in a randomized complete block (RCB) design with three replications during 2009. Genotypes manifested significant (p≤0.01) differences for days to first flowering, locules boll-1, seeds locule-1, lint % and seed cotton yield plant-1. The F1 hybrids showed significant increase over parents in mean values for all the traits. The correlation of seed cotton yield was significantly positive with majority of yield traits and negative with days to first flowering and lint %. Mean squares due to general (GCA) and specific combining ability (SCA) were highly significant for all the traits, except locules for GCA. Mean squares due to GCA were higher in magnitude than SCA for majority of the traits and their inheritance was mainly governed by additive type of gene action and partially by non-additive. Selection in such promising hybrids could be used in segregating generations, and also some specific cross combinations can be used for hybrid cotton production to increase the seed cotton yield. The best general combiners (CIM-446 and CIM-554) followed by CIM-496 and their utilization as one of the parents produced best specific F1 hybrids (CIM-446 × CIM-499, CIM-446 × CIM-554, CIM-496 × CIM-707 and CIM-506 × CIM-554) having valuable SCA determination and remarkable mean performance for most of the traits. Reciprocal crosses having prominent maternal effects also involved one of the general combiners for majority of the traits. The promising hybrids also exhibited earliness through which the crop can escape from pests attack and soil can be vacated earlier for following crop like wheat. However, it was also concluded that we could not rely on F1s only, however, the combined performance of F1 and F2 hybrids could be a good selection criteria to identify the most promising populations to be utilized either as F2 hybrids or as a source population for further selection in advanced generations.
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