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Wheat Information Service
Number 90:7-12 (2000)
Research article
Inheritance of flag leaf in bread wheat
genotypes
Naeem Mahmood and Muhammad Aslam Chowdhry
Department of Plant Breeding and Genetics, University of
Agriculture,Faisalabad, Pakistan
Summary
A 6x6 diallel analysis was conducted for the estimation of gene
action, combining ability and heterosis for flag leaf parameters in
wheat. Additive, gene action and partial dominance was observed for
flag leaf area and flag leaf weight, respectively. While dominance
and overdominance were observed for specific flag leaf area and
specific flag leaf weight. High heterosis for flag leaf traits was
observed in the hybrids involving LU26S or 4072 as one of the
parents. These parents were also good general combiners for these
traits and thus, are suggested as useful to be incorporated in the
future breeding program for improving flag leaf characteristics in
wheat.
Key words: Flag leaf, Specific flag leaf, Additive, Dominance,
Heterosis
Introduction
Flag leaf or the top most leaf in cereals is the most effective
photosynthetic structure as compared to other green parts of the
plant. Similarly in case of wheat, most of the photosynthates or
assimilates accumulated in the grain in the form of starch and other
carbohydrates are translocated mainly from the flag leaf. Ibrahim and
Abo Elenein (1977) found that the flag leaf contributed 41-43% to the
grain weight due to increase in kernel weight and number per spike
since the flag leaf is photosynthetically the most active leaf during
grain formation stage. Photosynthetic efficiency also relates to the
amount of light interception and flag leaf is the one where maximum
light interception can be obtained in cereals like wheat. Therefore,
cultivars with greater flag leaf area generally have high grain
weight. Monyo and Whittington (1971) obtained a significant positive
correlation coefficient of 0.41 for the association between grain
yield per tiller and flag leaf area in wheat. Similarly Briggs and
Aytenfisu (1980) recorded a positive and significant association of
flag leaf area with grain yield per plant and 1000-grain weight.
Although genetic studies pertaining to flag leaf parameters (flag
leaf and specific flag leaf area and weight) have been occasionally
conducted by few scientists (e.g. Briggs and Aytenfisu 1980), this
information is insufficient. Genetic information like gene action,
combining ability and heterosis for these traits will be helpful for
the breeders to select potential genotypes/combinations that may be
incorporated in productive breeding project.
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