Showing papers in "Journal of Genetics in 1977"
16 citations
TL;DR: It is found feasible that pure additive gene action at individual genic level coupled with a favourable additive x additive interaction can produce heterosis when gene frequency differences can be ensured and implications to problems in plant breeding are discussed.
Abstract: An expression for heterosis over midparent is derived for characters governed by one gene when hybrids are made using arbitrarily inbred parents. It is shown that, so long as inbreeding does not depress the vigour and fitness of parents, heterosis in hybrids between them will be greater than that obtained in hybrids between open-pollinated parents. The expression derived tor heterosis for characters governed by two genes has brought to focus the possibilities of obtaining heterosis without the presence of dominance etfects, and also of dominance interactions. Arguments are advanced to illustrate that pure dominance hypothesis alone cannot account tor the observed heterosis when the character is under the control of more than one gene. It is found feasible that pure additive gene action at individual genic level coupled with a favourable additive x additive interaction can produce heterosis when gene frequency differences can be ensured. Implications of thisresult to problems in plant breeding are discussed.
15 citations
TL;DR: It was unexpectedly found that increasing the ratio of females to males at the first mating did not lead to enhancement of the level of partial compatibility when the males were re-mated.
Abstract: Previously reported effects of aging and mating history in causing partial loss of cytoplasmic incompatibility in males of Paris cytoplasmic type, have been shown also to occur in males with Delhi and Hamburg cytoplasmic types. It was unexpectedly found that increasing the ratio of females to males at the first mating did not lead to enhancement of the level of partial compatibility when the males were re-mated. The effect of aging is discussed in relation to the use of cytoplasmic incompatibility integrated with chromosomal abnormalities, for genetic control.
4 citations
TL;DR: In this paper, the authors present results of backcrossing the F1 females and of further crosses which suggest that the genetic situation causing sterility is the simultaneous presence, in a male, of the Y chromosome of one species and of a gene from the X chromosome of the other species.
Abstract: It is well established that in crosses betweenAnopheles atroparvus andA. labranchiae, F1 males are sterile while the females are fertile. This paper presents results of backcrossing the F1 females and of further crosses which suggest that the genetic situation causing sterility is the simultaneous presence, in a male, of the Y chromosome of one species and of a gene (or genes) from the X chromosome of the other species.
3 citations
TL;DR: It is suggested that the loss of the green pigment and the retention of brown pigment in the lint fibres of primitive cultivars may have been influenced by human selection, which favours the view that wild forms of cultivated species are originally wild — not feral — types.
Abstract: Two genetic systems control the pigmentation of seed fibres inGossypium. In the New World amphidiploid cottons, and probably too in many of the wild diploid species, the green colour is controlled by members of a series that includes a minimum of three alleles:
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(green lint),
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(green fuzz),
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(white).
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is only known as a mutant in Upland cottons, while
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(or a similar allele) is probably common to wild and primitive cultivars ofG. hirsutum andG. barbadens G. tomentosum, G. mustelinum, and several wild diploid species. The recessive,
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, has not been found in any wild form ofGossypium.
3 citations
TL;DR: It has been found that linkage decreases or increases the average and standard deviation of time to fixation of a coupled gamete according as the initial population consists of a coupling or repulsion heterozygote respectively.
Abstract: A theory of the stochastic change in the frequency of a gene in finite populations conditional to its eventual fixation has been developed employing a Condiditional Markov Chain. The probability generating function of the distribution of time until fixation of a particular allele as well as the eigen-roots and eigenvectors of the conditional process with binomial transition probabilities have been studied. The theory has been applied to investigate the effect of linkage on the mean and standard deviation of time until fixation of a gamete in populations practising self-fertilization. It has been found that linkage decreases or increases the average and standard deviation of time to fixation of a coupled gamete according as the initial population consists of a coupling or repulsion heterozygote respectively.
2 citations
TL;DR: A, AB and B phenotypes of acid phosphatase were seen among all the groups, and it is suggested that they are quite homogeneous.
Abstract: A total of 1241 blood samples from 15 Dhangar groups — a semi-nomadic population, were studied by starch gel electrophoresis for haptoglobin and acid phosphatase types.
2 citations
TL;DR: The mutation spectrum induced with different doses of gamma rays in different genotypes of mung is studied to study whether gamma-rays have any specificity of action to different quantitative characters, and the pattern of shift in means and variances of various quantitative traits as a result of gamma-ray treatment is analysed.
Abstract: Induced mutations can be used to generate useful variations in quantitatively inherited characters. Appropriate selection can be then applied for improvement in yield, adaptability, time of maturity, disease resistance, and other characters such as seed \"quality\". A large number of characters have been reported to be improved by a combination of such mutagen treatment and selection in various crops (Micke, 1975). The work will, however, be facilitated ~f some specificity between mutagens on one hand and loci on the other could be established and if it would be possible to predict the spectrum of mutations. Little information is available on these aspects of crop improvement in mung. The present study was therefore planned in order to: (a) study the mutation spectrum induced with different doses of gamma rays in different genotypes of mung, (b) study whether gamma-rays have any specificity of action to different quantitative characters, and (c) analyse the pattern of shift in means and variances of various quantitative traits as a result of gamma-ray treatment.
1 citations
TL;DR: The inheritance of two new sex-linked mutants designated as ‘small-antenna’ (sma) and ‘broken-appendage” (brap) isolated from laboratory strains of Culex p.
Abstract: This paper describes the inheritance of two new sex-linked mutants designated as ‘small-antenna’ (sma) and ‘broken-appendage’ (brap) isolated from laboratory strains ofCulex p. fatigans. Both are recessive with partial penetrance and reduced expression in heterozygous condition.