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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.
1Department
of Plant Breeding and Genetics, Khyber Pakhtunkhwa Agricultural
University, Peshawar, Pakistan.
2Department
of Weed Science, Khyber Pakhtunkhwa Agricultural University, Peshawar,
Pakistan.
3Department
of Soil and Environmental Sciences, Faculty of Agriculture, Gomal
University, Dera Ismail Khan, Pakistan.
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