Showing papers on "Diallel cross published in 1974"

Genetic studies in heavy metal tolerant plants

Abstract: The genetics of zinc tolerance in Anthoxanthum odoratum was examined using the technique of pair crosses, and diallel analysis. Evidence is presented that the genetic control of zinc tolerance is (a) dominant and directional, (b) under a polygenic control system probably with a small number of loci involved, (c) not under any maternal influence. The parents have been shown to be highly heterozygous.

Combining ability studies in tomato (Lycopersicon esculentum Mill.).

Abstract: Diallel analysis was carried out involving eight diverse varieties of tomato, namely Pusa Early Dwarf, Sl-1, S-12, Punjab Tropics, Sl-120, HS-101, Pusa Ruby and Sl-73-1, to characterize the gene action involved in the inheritance of some of the quantitative traits and to correlate array mean and per se performance with general combining ability (gca) and specific combining ability (sca) effects, respectively. The results indicated that the variance component due to general combining ability was higher than that due to specific combining ability for yield and number of fruits, showing preponderance of an additive type of gene action. On the other hand, all other characters — height, number of branches, locule number, T.S.S., acidity and ascorbic acid content — were found to have a high variance component due to specific combining ability, which means excess of non-additive type gene action. In such cases, heterosis breeding, or any other breeding plan which makes use of specific combining ability effects, would be more effective. High correlation between parental array means and gca effects and between per se performance of the crosses and the sca effects was observed. The implications of the results are discussed.

Genetical and environmental variation for resistance to bacterial blight of upland cotton

Abstract: The inheritance of resistance in Upland cotton to Xanthomonas malvacearum was investigated using a half diallel set of crosses between six inbred varieties. Parents and progeny were inoculated and examined at three sites: Shambat and Wad Medani in the Sudan, and Namulonge in Uganda. In the Sudan, leaves only were inoculated. At Namulonge leaves and bolls were inoculated and two bacterial cultures were used on the latter organs. Diallel analyses based on those developed by Hayman, Jinks and Allard were computed. Special note was taken of non-additive genetic relationships. Dominance was found to account for non-additivity, and the data were examined for interactions involving sites and bacterial cultures. The behaviour of the B7 gene was not consistent with its being a simple Mendelian locus with incomplete dominance. Genetic variances varied with inoculum, being lower with culture NCG 40 than with NCC 38. Line 4, 101-102B, contains a polygenic complex in addition to genes B2 and B3. It has outstanding resistance and could be invaluable breeding material. Progeny of 101-102B demonstrate that resistance built up by selection of minor genes can be effectively transferred.

The genetics of stomatal length and frequency in clones of bromus inermis and the relationships between these traits and yield

Abstract: Stomatal length and frequency were studied using a 7 × 7 diallel cross of smooth bromegrass (Bromus inermis Leyss.) clones and compared with data from an earlier study of the agronomic traits of the crosses. Silicon rubber impressions taken on different parts of a leaf, as well as on different leaves, showed that though variation was small for stomatal size, it was present for stomatal frequency. General combining ability was highly significant for both stomatal characters. Differences among the seven clones were marked. Both stepwise multiple regression and factor analysis were used to investigate the dependence structure that existed for stomatal and agronomic characters. Partial regression coefficients showed that stomatal frequency was related to yield. Factor analysis showed that the two stomatal characters accounted for 20% of the total variation in the dependence structure, whereas characters such as date of head emergence and plant height only accounted for 15%. These results reflect the importanc...

Parental generation in relation to combining ability analysis in spring barley.

Abstract: A comparison between Griffing's (1956) Method 1, Model I, and Method 3, Model I, using data from a 10 × 10 diallel of spring barley grown in eight different environments, revealed that inclusion of the parental generation (Method 1) caused considerable upward bias in the estimates of both the general and specific combining ability variances, whereas its exclusion (Method 3) from the analysis resulted in similar GCA∶SCA ratios in all the environments. This investigation supports the exclusion of the parental generation in combining ability analyses. The proportion of general combining ability variance was much higher than that of the specific combining ability variance although both were statistically significant. The interaction of the former with environment was much higher than that of the latter. Except for combining ability variances, the estimates of GCA and SCA effects were found to be alike in both Method 1 and Method 3. Mean performance was correlated with the general combining ability effects. Variety Cb 824 proved to be the best general combiner for earliness; it could be usefully exploited in future breeding programmes to induce earliness, as this variety possesses mostly dominant genes for earliness. Early varieties such as Otis, Bonus M-12a and Line 7-2 were also good combiners for earliness. Crosses between these varieties generally showed high specific combining ability effects.

The inheritance of behavioral wildness in house mice (Mus musculus L.)

Abstract: Fourteen behavioral measures were ranked according to their ability to differentiate performances of a wild population of mice from three domestic inbred strains. These “wildness” rankings were then analyzed for their ability to predict genetic and Genotype by Environment interactions. Genetic parameters were derived from analysis of three inbred domestic strains and their three hybrid crosses via the diallel technique of genetic analysis. Genotype by Environment interactions were assessed both as mean differences in stock performances resulting from rearing in a laboratory vs naturalistic environment and as differences in environmental variability within stock genotypes. Behavioral characters ranking high on “wildness” failed to demonstrate any unitary pattern of Genotype by Environment interactions. The diallel genetic analysis revealed many examples of additive variation but relatively few examples of dominant variation. An extremely wide range of interactions occurred between genotype and rearing environments, with “wildness” and “developmental homeostasis” concepts both failing to account for all the observed interactions.

Combining Ability in Upland Cotton—Ginning and Fibre Characters

Abstract: An 8 × 8 diallel analysis of combining ability was conducted to characterise the genetic architecture of the population and to isolate best parents for hybridization aiming to improve ginning and fibre properties in Upland cotton (Gossypium hirsutum). The variances due to general and specific combining ability, both, were significant for all the six characters, (G.O.T., seed index, lint index, fibre length, fibre strength and fibre fineness) studied. The magnitude of general combining ability variances was, however, about four to six times higher than those due to specific combining ability. A breeding plan which may mop up the additive gene effects effectively and can maintain certain degree of heterozygosity in cotton has been suggested for maximum exploitation. The Punjab strain A102 was the best general combiner for four of six characters (seed index, lint index, fibre length and fibre fineness). The per se performance of the parents had high relationship with their general combining ability effects. The genetic and geographic diversity of the parents had high association with their specific combining ability

The inheritance of resistance to Rhynchosporium secalis in some European spring barley cultivars

Abstract: SUMMARY The inheritance of partial resistance to Rhynchosporium secalis, which appears to be race non-specific, was studied in a diverse range of European spring barley cultivars. Data from the F2 generation of a 6 × 6 diallel cross and the F3 generation of three crosses selected from this diallel set suggested that resistance was complex in inheritance, the results being incompatible with any hypothesis involving less than four genes. The F2 studies indicated that both dominant and recessive genes were active in conferring resistance, and that there were significant additive gene effects. Transgressive segregation occurred in all cross combinations in the F3 material. Consequently the alleles conferring resistance were not completely concentrated in the most resistant cultivar studied (cv. Proctor). Heritability estimates obtained from F2 and F3 material suggested that field selection was of limited reliability, even when spreader drills were incorporated amongst the segregates. Single-plant selection (in F2) was considered to be of little value, and the results of Fa head-row tests would require confirmation by replicated tests in subsequent generations.

General and specific combining ability in lucerne at different levels of in breeding and performance of second-generation synthetics measured in competitive conditions

Abstract: In a breeding program of lucerne based on selfing in sward conditions general as well as specific combining ability was evaluated for diallel crosses made at different levels of inbreeding. The performance of the second generation synthetics was studied as well. The efficiency of selfing and subsequent selection in improving the genetic value of parents is very important. The optimal solution for lucerne breeding could well be the use of synthetic varieties which are based on 4 inbred clones.

Water escape learning in mice. III. A diallel study

Abstract: A 5×5 dialled cross was used to investigate the mode of inheritance of water escape learning in mice. Strains C3H and ICFW had a poor learning performance, while strains DBA/1, CBA-T6, and C57BL/10ScSn improved their performance markedly in successive trials. There was evidence for heterosis and reciprocal cross effects, but no evidence for sex differences. General combining ability was low, but specific combining ability-high. Heritability was calculated as 0.07 (narrow sense) and 0.73 (broad sense). Variance/covariance analysis indicated a dominant to overdominant polygenic mode of inheritance with no epistasis, although the males showed less dominance and less variation between strains than the females. The most recessive genes were carried by the strains with a poorer learning performance, i.e., ICFW and C3H.

Genetical studies of quantitative characters in peas. 3. seed and seedling characters in the F2 of a six-parent diallel set of crosses

Abstract: Very little information is available on the genetics of seed size and the initial stages of plant development in peas. An experiment involving F2 material available from a full 6 x 6 diallel set of crosses involving 2 wild forms, 2 primitive and 2 European cultivars was set up to investigate a number of plant characters. These were seed weight, seedling shoot and root length and the number of lateral roots at 6, 7, 8 and 9 days after germination, and shoot and root fresh weight at 9 days.

Heterosis and combining ability in Phaseolus aureus roxb

Abstract: Heterosis and combining ability were estimated in F 1, F 2, F 3 and backcross generations of diallel cross in Phaseolus aureus. Hybrid vigour for yield compared with the mid-parent and better parent was noted in 21 and 20 F 1 hybrids, respectively. There was an appreciable amount of inbreeding depression in the F 2 and F 3 compared with the F 1 hybrids. Pod number seems to influence yield to a great extent. As expected, the high-yielding hybrids resulted from crosses between parents of diverse geographic origin. Combining ability analysis revealed that both g.c.a. and s.c.a. variances were important for yield, while g.c.a. variance was more important for seed size, pod number, cluster number and pods per cluster. The g.c.a. variance for yield appeared to be influenced by g. c. a. variances for yield components. In general, the crosses having high s.c.a. had one of the parents as high combiner for yield and other traits. The diallel study of different generations gave a comprehensive picture of combining ability.

Genetic analysis of plant height in wheat.

Abstract: Genetic studies of plant height were made of 8 wheats and the 28 crosses between them using the diallel method of analysis. The inheritance of plant height in a glasshouse-grown F1 diallel set in which vernalization and photoperiodic responses had been removed, indicated close to complete dominance in its expression. A similar F1 set of crosses in the field environment indicated non-allelic interaction in its expression, attributable mainly to the cultivar Chile 1B generally in its crosses with the other 7 wheats. Its removal gave close to complete average dominance in the inheritance of plant height. In the F2 generation in the field its inheritance was again subject to non-allelic interaction, attributed mainly to Chile 1B which, on removal, gave a situation of average partial dominance in height expression. Standardized deviations of Yr and (Wr + Vr) for plant height for the diallels indicated a resonably close association of tallness with dominance and shortness with recessiveness. Frequency distributions of plant height in the F1 and F2 of two crosses from the diallel confirmed certain findings of the diallel analysis. At least two groups of dominant genes were found to influence plant height expression in the crosses of the diallel ; this number must be regarded as a minimal estimate of the number of genes influencing plant height in wheat.

Additive and non-additive genetic variance in odontometric traits in crosses of seven inbred lines of house mice.

Abstract: A least-squares diallel analysis of the offspring of crosses of seven inbred lines of house mice was performed for the mean widths of the second (M 2 ) and third (M 3 ) mandibular molars. Significant differences among lines, as well as between inbreds and hybrids (positive heterosis) were found for these characters. Estimates of the heritabilities (from general combining ability variances) were high for both teeth as were estimates of maternal effects. Specific combining ability and reciprocal effects were significant only for the M 3 . Additionally, X-irradiation reduced the mean number of individuals per litter, and thereby indirectly influenced the widths of both molars.

Analysis of fruit yield and related factors in a diallel of seven inbred strawberry clones

Abstract: A diallel of seven inbred clones of the domestic strawberry was evaluated for 5 variables and was compared with the standard cultivar Redcoat. For fruit yield, berry size, date of mid-harvest, and ...

The nature of gene action and combining ability for some vegetative characters in tomato

Abstract: Greater height and low intensity of branching were found to be completely dominant characters. Partial dominance for dry weight is indicated after using a reduced diallel to fulfil the underlying assumptions. For height and dry weight, the parents can be categorized into two groups, one having predominantly dominant genes and the other having predominantly recessive genes. This grouping, however, is not marked for intensity of branching. The groups correspond to determinate and indeterminate types, and maximum amount of heterosis is observed in crosses involving parents from different groups.

Diallel Analysis in Soybean

Abstract: A diallel study for six quantitative characters in soybean was conducted at Punjab Agricultural University, Ludhiana, during kharif 1972. The study revealed that complex characters, like grain yield, pods and clusters per plant, were controlled by both additive and non-additive gene action. The discrepancy in the estimation of genetic components of variance through various analyses may have arisen due to the presence of interallelic interactions. For 100-grain weight and plant height additive genetic variance was highly significant, though non-additive variance also played some role in the inheritance of seed weight. The parent Bragg in general and the cross Bragg × Semmes in particular were observed to be good and should be exploited. Breeding procedure based on gene action has been suggested

A general approximate method for fitting additive and specific combining abilities to the diallel cross with unequal numbers of observations in the cells

Abstract: A method is given and illustrated by examples, for the analysis of incomplete diallel tables including the calculation of the coefficients in the expectations of mean squares. The method is applicable to any of the four basic diallel mating designs.

Combining Ability in Brinjal

Abstract: Combining ability analysis of nine quantitative characters was made through a 7 × 7 diallel cross in brinjal. General combining ability variance was found significant for all the characters. Additive genetic variance had a predominant role in the expression of all the characters as g.c.a. variance was found much higher than the s.c.a. variance. Varieties T. 2 and T. 3 were found the best general combiners. These varieties were followed by BGL>BBR> PPL> WB>KBL in respect of number of characters for which they have given positive g.c.a. effects. The crosses involving either T. 2 or T. 3 were good specific combiners. The cross T. 2 × T. 3 was found the best specific combiner for yield. This cross can be utilized both for developing high yielding lines by selection and for exploiting hybrid vigour.

Partial diallel crosses based on extended triangular association scheme

Abstract: Procedures of constructing and analysing partial diallel crosses based on extended triangular association scheme (ETD) where the number of parental lines is of the form p(p-l) (p-2)/6 with p as an integer greater than 3 have been discussed. It has been found that these plans for partial diallel crosses are clearly more efficient than those based on circulant Designs (CD) for the same number of crosses sampled.

A study of combining ability for grain protein percentage in a diallel cross of five six-row barley cultivars

Abstract: Grain protein percentage was assessed in F1 and F2 populations in two experiments involving a complete diallel cross among the barley (Hordeum vulgare L.) cultivars Bonanza, Conquest, Olli, Galt and Jubilee. Heterosis was absent in all crosses and a Griffing combining ability analysis showed that specific combining ability was nonsignificant in both F1 and F2 populations. General combining ability (GCA) for protein percentage was highly significant in both generations, with Conquest and Olli having major positive GCA effects. Galt produced a large negative GCA effect, while Jubilee and Bonanza caused small negative GCA effects. Significant differences between the hybrids were found only in F1. Broad sense heritabilities for protein differences between the parents were 0.57 and 0.72 in the two experiments, and were significant at the 5 and 1% levels of significance, respectively. Conquest had significantly higher protein than Bonanza, with Olli being intermediate. Galt had lower protein than Jubilee, but t...

Combining ability for kernel plumpness in a diallel cross of five canadian barley cultivars

Abstract: A complete diallel cross of Bonanza, Conquest, Galt, Jubilee, and Olli barley was made and the parents, F1 and F2 bulks, were subjected to a kernel-sizing procedure, using five different standard sieves. Mean values for the P, F1, and F2 were obtained and heritabilities and estimates of general (GCA) and specific (SCA) combining ability were calculated. Reciprocal effects were not significant in either F1 or F2. For the F1 data significant differences could only be found on the 19 × 2.4-mm (3/4 × 6/64-inch) sieve. Only GCA was significant for the F1, suggesting additive gene action. By contrast, in the F2 GCA was highly significant for all sieve sizes from 19 × 2.2 mm (3/4 × 11/128 inch) upwards, and SCA was significant on those of size 19 × 2.4 mm (3/4 × 6/64 inch) upwards. For the F2 on the 2.4-mm (6/64-inch) screen, the SCA effect exceeded the GCA effect in magnitude, and was in a negative direction, contributing to the two cases of negative heterosis for kernel plumpness. No significant positive heter...

Diallel Analysis of Yield and its Components in Pea

Abstract: A quantitative genetic study of the inheritance of yield and its certain components was carried out with 5 varieties of garden pea from parents, F1 and F2 progenies utilizing the Jinks-Hayman diallel cross analysis technique. Tests revealed that all the assumptions underlying diallel cross analysis were more or less fulfilled. Both additive and non-additive genetic components were significant for no. of primary branches, pod length and 25-seed weight although the former was predominant in the first two traits while non-additive component was high in 25-seed weight. Only additive genetic variance was significant for no. of pods/plant and no. of seeds per pod while only dominance was significant in F1 generation of seed yield/plant. Narrow sense heritability value indicated that rapid genetic advance through selection could be made in all traits except 25-seed weight and seed yield per plant.