| Monosomic analysis in wheat (Triticum aestivum
L. em. THELL.): Study of glume pubescence and awn colour*
S.R. BHAT and J.V. GOUD college of Agriculture, Dept. of Agricultural Botany, Dharwar 580005, Karnataku, India Studies on the nature of inheritance of qualitative characters in wheat species have been numerous but inconclusive. Aneuploid analysis was suggested in polyploid species like hexaploid wheat where several duplicate loci make the conventional genetic analysis difficult. But still, with only a few markers the monosomic analysis demands considerable labour. Therefore with an idea of establishing gene chromosome markers, two qualitative characters glume pubescence and awn colour were studied by monsomic F2 analysis method whose results are presented in this paper. Glume pubsscene is one of the good markers and genetic studies have indicated single dominant gene controlling this character (PAL et al., 1956; SIKKA and RAO, 1957; SUVA et al., 1958 and SRINIVASAN, 1962). Allelic series Hg, hg and hg2 conditioning glume pubescence was proposed by SHEYBANI and JENKINS (1961). Hg is a dominant gene for pubescence ; glabrous condition, hg, is recessive to Hg but dominant to hg2 for pubescence. Chromosome 1A has been found to carry a gene for glume pubescence in varieties Sonora (KUSPIRA and UNRAU, 1960), Loro (ANDERSON and MCGINNIS, 1960), Prelude and Fife (TSUNEWAKI, 1961). Black awn colour has been found to be dominant over white (KHAN, 1956) and linkage is noticed between the genes controlling awn colour and glume pubescence with a cross over value of 12.33 + or - 2.16 (SIKKA et al., 1961). Epistatic (SUVA et al., 1958) and complementary (ASLAM, 1958) gene actions have also been proposed to explain awn colour inheritance. Material and Methods The material for the present study comprised of one disomic and nineteen monosomic F2 populations of the crosses between disomic and nineteen monosomic lines of Pb. C591 (except 1A and 4A) with UP 301 pollen. Monosomic condition was identified before making the cross and also in the F1 by chromosome counting in mitosis and meiosis. The material was sown in a randomised block design with three replications in the Botany Garden, Agriculture College, Dharwar during October 1976. Glume pubescence and awn colour of individual F2 plants were recorded by visual observation at the time of maturity. Chi-Square test was applied to test the goodness of fit of the assumed phenotypic ratios. In critical lines, where the assumed ratios showed a strong deviation, expected frequencies of different phenotypic classes were calculated, assuming the presence of genes under study on those chromosomes, and Chi-Square test was again applied to confirm the assumption. |
| * Part of the M. Sc. (Ag.) thesis submitted by the Senior Author to the University of Agricultural Sciences, Bangalore, India |
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