Showing papers on "Diallel cross published in 1980"

Interspecific hybridization in Cucumis L.. II. The crossability of species, an investigation of in vivo pollen tube growth and seed set.

Abstract: The crossability of 12 Cucumis species of African and Asiatic origin was studied in a diallel cross, in order to find ways to realise the cross between the common cucumber (C. sativus L.) and its wild relatives which carry resistances against diseases and pests. Self-pollinations and cross-pollinations within species gave normal pollen tube growth and seet set. The different accessions within a species, as a rule reacted alike in interspecific crosses. In crosses between African species different crossing patterns were found, viz. bilateral congruity, bilateral incongruity and unilateral incongruity. Within C. sativus all accessions intercrossed freely, except one, which displayed unilateral incongruity. Good seed was harvested from several crosses and in some cases embryo culture was needed for further development of seeds. No good seeds were obtained from any cross between a species of the African group and C. sativus L.

Inheritance of seed protein content and other agronomic characters in long bean ( Vigna sesquipedalis Fruw.)

Abstract: Seven varieties of long bean, which included three local and four exotic, were crossed in a complete diallel. This was an attempt to study the inheritance of crude protein content, protein yield, flowering date, pod yield and yield components. Both additive and non-additive gene effects were responsible for the genetic variation in the diallel population. However, dominance variance was more important than additive variance in crude protein content, number of pods per plant and number of seeds per pod. For seed weight and pod length, additive variance was more important. The crude protein content, protein yield and number of pods per plant appeared to be controlled by overdominance effects. Partial dominance seemed to be the case for flowering date, pod length and seed weight; complete to overdominance for pod yield. High protein appeared to be associated with recessive genes whereas there was a general trend of high yielding parents carrying more dominant genes.

The effect of accidental selfing on the analysis of a diallel cross with sugar cane.

Abstract: The diallel cross was found to be an unsuitable design for quantitative genetic analyses with sugar cane.

Combining ability and maternal effects in Brassica campestris L. var. ‘yellow sarson’

Abstract: A diallel analysis of combining ability, including maternal effects, genotype X environment interaction and the progress under selection, is reported in three selected crosses of Brassica campestris L. var. 'yellow sarson', involving 15 types, including 10 four-valved and 5 two-valved types from different parts of India. Twelve characters, including oil content, were studied in the f1 generation.The investigation has revealed only marginal superiority of f1's over the parents for most of the characters related to yield. There was no relation between heterozygosity and stability of performance over environments for yield or its components or for oil content. Substantial maternal effects were observed which also interacted with environments. Creation of variation for primary and secondary branches would be essential for changing yield level in 'yellow sarson'. The presence of limited additive variation available for selection for yield components should be augmented by biparental mating the early segregating generations to break linkages, and was demonstrated by the recombinants obtained when this method was adopted.The magnitude of genotype - environment interactions in this study, as compared with the total genetic components for yield, oil content, number of siliquae on main axis and presence of large reciprocal variances in relation to general and specific combining ability variances for practically all characters, and the large interaction of [Formula: see text], narrowed down the expected effectiveness of selection.Biparental mating in the three best crosses yielded three new recombinants outyielding the best check T 10 by the margins of 14%, 39% and 15%, respectively, in the yield trial. These recombinants had more primary branches and secondary branches, larger main axes and more siliquae with an increased number of seeds per siliqua, than any of the F1's in this study.

The genetics of Drosophila melanogaster courtship song—Diallel analysis

Abstract: MALE Drosophila melanogaster produce a courtship song by vibrating their wings, in a specific code by which females identify conspecific males. It also stimulates the female to copulate (Bennet-Clark, Ewing and Manning, 1973). The sound is made up of sine song and pulse song. The time interval between pulses (the interpulse interval (ipi)) is important in discrimination between species. Different species produce different ipi's, but females only respond to the ipi of their own species (Bennet-Clark and Ewing, 1969). The ipi's of a male vary in length, and the mean ipi's of different laboratory strains also differ. I have sought to establish whether females recognise a range of ipi values and if so, how wide this range is? If it were narrow then some males' ipi's would fall outside it, and would presumably show reduced fitness. The character would thus be subject to stabilising selection in which fitness is highest at a phenotypic optimum. Alleles which always made for higher fitness would be favoured and might then be expected to evolve to a dominant state (Fisher, 1930), but with stabilising selection neither increaser nor decreaser alleles show an unconditional advantage. The commonest alleles should then show dominance (Fisher, op cit.). Thus characters under directional selection would be expected to evolve unidirectional dominance, whereas characters under stabilising selection would show weaker dominance of an ambidirectional kind (Mather, 1973). In addition some characters will make a larger contribution to fitness than others, and the \"fitness\" characters will have a larger ratio of dominance to additive variation than the so called \"peripheral\" characters (Robertson, 1955). I report here on the genetical architecture of both ipi and sine song frequency (ssf). The function of the latter is not fully understood, but Schilcher (1976) reports that it may not be involved in species identification.

Breeding research on rose pigments. II. Combining ability analyses of variance of four flavonoids in F1 populations

Abstract: 18 Hybrid Tea-rose varieties were crossed and selfed in an incomplete diallel. In F1 seedlings the relative contents of the flavonoids: pelargonidin, cyanidin, kaempferol and quercetin, were determined by means of paper chromatography. Inheritance of each pigment was mainly controlled by additive gene action. Combining ability analyses of variance of these pigments showed highly significant differences between GCA's of the varieties. The pigment content of parent varieties can be a useful basis for breeding.

Quantitative genetic aspects of nitrogen fixation in peanuts (Arachis hypogaea L.).

Abstract: Manipulation of the host genotype has been proposed as a method of increasing biological nitrogen fixation by rhizobia in symbiosis with the peanut (Arachis hypogaea L.). The F1 generation of a diallel cross of 10 South American cultivars was evaluated in the greenhouse in an analysis of gene action for traits related to nitrogen fixation. The parents represented five secondary centers of diversity and effects in the diallel model were partitioned into among- and within-center components. Variation of center effects was significant for several characters but was smaller in magnitude than within-center variation. Specific combining abilities were significant and accounted for more variability than general combining abilities for nodule number, nodule mass, specific nitrogenase activity, shoot weight, and total nitrogen, indicating non-additive types of gene action. Maternal effects were observed for the same characters. The parents with the highest general combining abilities (GCA's) for nitrogen fixation were both fastigiate types, while Virginia-type parents had generally low GCA's. Correlations between parental and GCA effects were nonsignificant for all traits, so simple evaluation of lines for nitrogen-fixing capacity may not identify superior parents for use in breeding programs

Diallel analysis of flowering-time in corn (zea mays) using a corn heat unit transformation

Abstract: A set of eight corn (Zea mays L.) inbreds was studied in a diallel cross over two years and in a growth room to investigate general and specific combining ability for flowering-time. Diallel analysis of days from emergence to flowering revealed a failure of the joint Wr/Vr regression in one of the years, indicating a lack of agreement with the simple additive-dominance model of inheritance. The array position changed across the years and environments, complicating genetic interpretation. Transforming data of flowering-time to cumulative corn heat units (CHU) to flowering gave a better fit. Joint regression was satisfactory and array position was more consistent across years and environments. Dominance was incomplete for low CHU to flowering. Positive (increasing CHU) and negative, as well as dominant and recessive, alleles were in about equal frequencies. Heritability estimates in the broad- and narrow-sense were high. The estimates of general combining ability were higher than the estimates of specific c...

Combining ability analysis of beta-Carotene, total carotenoids and other grain characteristics in pearl millet

Abstract: Combining ability studies with respect to grain quality characteristics viz., beta-Carotene, total carotenoids, protein content, 250-grain weight, grain hardness and grain yield were carried out from a 13x13 diallel cross set in pearl millet [Pennisetum typhoides (Burm S&H)].The parents versus hybrids comparison indicated significant heterosis for all the traits under study. In general the hybrids having higher grain yield had bold hard grains with more carotene but low protein content, although a few hybrids combined high yield with an average protein percentage. The relative proportions of the general and specific combining ability variances indicated predominance of non-additive genetic variance with respect to all the traits. The per se performance of parents provided a fairly good indication of their combining ability in most cases. Parents possessing desirable grain quality characteristics were identified. Breeding implications are discussed.

Genetical variation for enzyme activity in a population of Drosophila melanogaster. V. The genetical architecture, as shown by diallel analysis, of alcohol dehydrogenase (ADH) activity.

Abstract: Fifteen highly inbred lines extracted by sib-mating from the laboratory cage population, "Texas", of Drosophila melanogaster were crossed in a half-diallel mating design. Female progeny were assayed individually for ADH activity at 25 degrees and 35 degrees C and for total protein. At 25 degrees C there was considerable additive genetical variation and the dominance variation was attributable to specific parents and to specific crosses at random in the diallel table. The character total protein also showed considerable additive variation but less dominance variation. Largely independent gene action was shown by the characters ADH activity and total protein. There were strong genotype-environment interactions for heat-stability. At 35 degrees C most of the genetical variation was additive and mainly due to modifier loci. It was concluded that at 25 degrees C dominance was ambidirectional and almost complete. This genetical architecture was compatible with a past history of stabilising selection for ADH activity in the "Texas" population.

Combining ability in groundnut.

Abstract: Nine agronomic traits were studied in a six-parent diallel, without reciprocals, of Arachis hypogaea. Differences among progeny, together with general and specific combining ability mean squares, were significant for all traits. Additive effects strongly influenced all traits except leaflet width and seed weight. The biparental progeny approach is suggested for improvement of pod yield and it components

Genetic control of resistance to Kabatiella caulivora in Trifolium subterraneum subspecies yanninicum I. Diallel analysis of variation in disease development parameters

Abstract: A l0 x 10 complete diallel cross of Trifolium subterraneum subspecies yanninicum genotypes was evaluated for resistance to Kabatiella cauliuoua as F2 swards. Analysis of variance of the diallel cross data indicated that variation in 10 October disease score, total disease development (TDD), rate of disease development (Rate) and time to 50% of maximum disease rating (Delay) were heritable. Coefficients of regression of Wr on Vr were significantly greater than zero but not significantly different from a value of 1 for all four disease parameters. Although this evidence is not conclusive, it does suggest that gene interactions are relatively unimportant. Most non-additive gene action could be attributed to dominance effects and, in terms of both 10 October disease score and total disease development (TDD), a high proportion of alleles conferring resistance were dominant. No clear relationship between phenotype and relative proportions of dominant and recessive alleles was evident for either Rate or Delay. Estimates of dominance variance components were, with the exception of Delay, substantially greater than the additive genetic component. Values of F were positive for all parameters and, except for Delay, values of v(H1/D) were greater than 1, which indicated that dominant alleles are more frequent than recessive alleles among the parents and that dominance is complete at those loci exhibiting dominance. Heritabilities (broad and narrow sense) were substantially greater for TDD and 10 October disease score than for Rate and Delay. The implications of these results are discussed in relation to the development of efficient breeding strategies.

Doubled haploids for estimating additive epistatic genetic variances in self-pollinating crops.

Abstract: In this study it was shown that besides additive and additive × additive genetic variances, additive × additive × additive genetic variance can also be estimated from a diallel experiment in which each cross is represented by a number of doubled haploid lines.

Diallel analysis over environments in mungbean.

Abstract: The present study was made on 8 × 8 diallel cross (excluding reciprocals) in F1 grown over 3 different locations in northern India. The combining ability studies made over environments revealed that both g.c.a. and s.c.a. are influenced by locations. This suggested that to have unbiased estimates of g.c.a. and s.c.a. the studies be made over a wide range of environments. As additive gene effects were pre-ponderent, the pedigree method was suggested for getting pure lines with high pod and cluster number. Simultaneously, the diallel selective mating system among the good general combiners be followed for release of greater genetic variability.

Diallel analysis of heading date in rice (Oryza sativa L.).

Abstract: The genetics of heading date was investigated in an 8×8 diallel set of crosses involving diverse rice cultivars. Wr, Vr graph analysis revealed the presence of a complementary type of non-allelic interaction which apparently affected the position and slope of the regression line such as if there were overdominance. Omission of two interacting parents resulted in a 6×6 subset of diallel crosses from which, as observed in the Wr, Vr graph, the non-allelic interaction had disappeared and the regression line exhibited partial dominance. Estimates of the genetic components of variation were in close conformity with the results obtained from the Wr, Vr graph: the average degree of dominance, as measured by (H1/D)1/2, was in overdominance range in the interacting 8×8 set of diallel crosses whereas it was reduced to partial dominance in the non-interacting 6×6 set of crosses. Further analysis by a standardized deviations graph indicated that earliness was controlled, on the average, by an excess of dominant alleles.

The augmented partial diallel cross

Abstract: The augmented partial diallel cross is a design for estimating general and specific combining abilities in which one or more primary lines are crossed with all others, but the lines of secondary interest form a partial diallel cross. There are up to four variances of inter-line comparisons, depending on whether the lines are primary or secondary and whether they are crossed or not, and approximate expressions are given for these variances. The approximations are sufficiently accurate to determine the variance properties of any given design.

Combining ability and parental evaluation in five selected clones of sugarcane (Saccharum sp. hybrids).

Abstract: Five Hawaiian commercial sugarcane (Saccharum sp. hybrids) clones were crossed in a full diallel. Four morphological characters were studied in the progeny: number of millable stalks per plant, stalk diameter, stalk length, and sucrose content. A fifth character, plant volume, was calculated from stalk number, stalk diameter and stalk length. The five selected parental clones were treated as fixed variables in the analysis. General combining ability (gca) was significant for all five characters; specific combining ability (sca) was significant for stalk diameter, stalk length, and plant volume. The variance for gca was large in all progeny populations. However, the variance for sca was large in the progeny of only some clones and/or for some individual characters. Parents were evaluated on the basis of their general combining ability: clone H49-3533 had high gca for sucrose content, while clone H53-5356 had high gca for plant vigor.

Quantitative Genetic Aspects of Nitrogen Fixation in Peanuts

Abstract: Manipulation of the host genotype has been proposed as a method of increasing biological nitrogen fixation by rhizobia in symbiosis with the peanut (Amchis hypogueu L.). The F, generation of a diallel cross of 10 South American cultivars was evaluated in the greenhouse in an analysis of gene action for traits related to nitrogen fixation. The parents represented five secondary centers of diversity and effects in the diallel model were parhtioned into among- and within-center components. Variation of center effects was significant for several characters but was smaller in magnitude than within-center variation. Specific combining abilities were significant and accounted for more variability than general combining abilities for nodule number, nodule mass, specific nitrogenase activity, shoot weight, and total nitrogen, indicating non-additive types of gene action. Maternal effects were observed for the same chamcters. The parents with the highest general combining abilities (GCA’s) for nitrogen fixation were both fastigiate types, while Virginia-type parents had generally low GCA’s. Correlations between parental and GCA effects were nonsignificant for all traits, so simple evaluation of lines for nitrogen-fixing capacity may not identify superior parents for use in breeding programs.

Mixture diallel experiments with unequal proportions of genotypes.

Abstract: An analysis is suggested for an experiment investigating plant competition between different genotypes grown in pure culture and in binary mixtures with unequal proportions of genotypes. Worked examples are presented.

Genetic analysis of resistance to swede mildew

Abstract: SUMMARY The incidence of swede mildew (Erysiphe cruciferarum) was analysed on three occasions in five swede varieties Crifel, Doon Major, Harvester, Ne Plus Ultra and Ruta Otofte and their F1 hybrids. Overall levels of infection were greater in Ne Plus Ultra and Harvester and least in Ruta Otofte. Genetic analysis by the diallel method showed that initially resistance was recessive with Ruta Otofte possessing most recessive genes but results from the final analysis showed partial dominance, with Ne Plus Ultra having most recessive and Harvester most dominant genes. The changing pattern of inheritance with time was due to variation in the rates of increase in disease incidence and diallel analyses of these rates, calculated by regression analyses over five observations, showed in almost entirely additive control. Although no variety was immune it was considered that except on soils of high pH or in the event of a marked change in the genetic composition of the pathogen the level of resistance in Ruta Otofte was satisfactory.

Breeding for resistance to yellow disease of hyacinths. I. Investigations on F1's from diallel crosses.

Abstract: Analysis of an incomplete diallel design with 14 hyacinth cultivars for resistance to yellow disease showed a significant GCA and a heritability of 0.75. A correlation appeared to exist between flowering date and degree of resistance to yellow disease, early flowering seedlings being generally less resistant. Of 1440 seedlings 69 were selected as resistant on the basis of absence of leaf symptoms. The results of the selection appeared to be in agreement with the breeding value (GCA) of the parent cultivars. The possible influence of chromosome numbers on the degree of resistance to yellow disease is discussed.

A method of parental selection and cross prediction using incomplete partial diallels : Part 1: a simulation study.

Abstract: When a character has a large additive genetic component in its variance, general combining ability estimates may be used for predicting cross performance. Further, if emphasis is placed on the ranks of the general combining abilities in a diallel rather than on their numerical values, the incomplete partial diallel is a powerful tool for parental selection. In a self pollinating species, if general combining ability effects are equal to or greater than specific combining ability effects, 20% of the partial diallel is found to give enough information for accurate ranking of the parental general combining abilities. A generalised method for calculating general combining abilities from incomplete partial diallels is presented and tested by computer simulation over a large range of genetic population parameters.