Genetic control of flowering time in subterranean clover

1985 ◽  
Vol 36 (2) ◽  
pp. 275 ◽  
Author(s):  
BH Tan
Keyword(s):  
Flowering Time ◽  
Regression Coefficient ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Diallel Analysis ◽  
Diallel Cross ◽  
Quantitative Inheritance ◽  
Dominance Model ◽  
Degree Of Dominance ◽  
Asymmetrically Distributed

The quantitative inheritance of flowering time in autumn-sown subterranean clover (Trifolium subterraneum L. ssp. subterraneum) was studied in a 13 x 13 diallel cross in a Mediterranean-type environment. Flowering time was shown to be highly heritable with a low average degree of dominance, which was predominantly in the direction of earliness. Covariance/variance ( Wr/Vr) regression analysis indicated early flowering to be conditioned mostly by dominant alleles, and lateness mostly by recessives. The alleles were slightly asymmetrically distributed among the parents, with recessives marginally in excess. Inadequacy of the additive-dominance model, on which the Birmingham diallel analysis is based, was detected by a significant departure from unity of the joint regression coefficient and the heterogeneity among arrays of (Wr Vr) values, which could be ascribed to and overcome by omitting two late-flowering parents from the diallel cross.

The inheritance of flowering time in Trifolium subterraneum L

1957 ◽  
Vol 8 (2) ◽  
pp. 121 ◽  
Author(s):  
CI Davern ◽  
JW Peak ◽  
FHW Morley
Keyword(s):  
Genetic Variation ◽  
Flowering Time ◽  
Intraclass Correlation ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Diallel Analysis ◽  
Genetic Effects ◽  
Breeding Behaviour ◽  
Variable Factor ◽  
Additive Genetic Effects

The inheritance of flowering time in subterranean clover, using a number of strains and hybrids among them, was investigated on autumn-sown material at Canberra. Heterosis and dominance were not found, and genetic variation was polygenic. An F1 diallel analysis and F2 two-way analysis showed that approximately 90 per cent. of the total variance was attributable to additive genetic effects. An estimate of the repeatability of strain performance over two seasons showed that small but significant strain-year interactions were occurring. Strain repeatability, as measured by intraclass correlation, was 86 per cent. A breeding test involving F2 selections and their progeny gave a mean parent-offspring regression of 0.86 over the six crosses studied, which is well in accord with expectations of breeding behaviour based on the above analyses. The results are discussed in relation to other studies on flowering time, especially with reference to the problem of interpreting results based on the threshold expression of a character dependent on the value of a continuously variable factor.

DIALLEL ANALYSIS OF FLOWERING-TIME IN CORN (ZEA MAYS) USING A CORN HEAT UNIT TRANSFORMATION

1980 ◽  
Vol 22 (4) ◽  
pp. 633-640 ◽  
Author(s):  
S. B. Rood ◽  
D. J. Major
Keyword(s):  
Zea Mays ◽  
Flowering Time ◽  
Combining Ability ◽  
Zea Mays L ◽  
Diallel Analysis ◽  
Diallel Cross ◽  
Specific Combining Ability ◽  
Dominance Model ◽  
Genetic Interpretation ◽  
Array Position

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 combining ability in all studies.

Multi-allelic nature of the locus controlling leaf marking in subterranean clover

1987 ◽  
Vol 38 (3) ◽  
pp. 547 ◽  
Author(s):  
BH Tan ◽  
WJ Collins
Keyword(s):  
Recessive Gene ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Diallel Cross ◽  
Mendelian Inheritance ◽  
Alternative Interpretation ◽  
Parental Genotype ◽  
Origin And Evolution ◽  
Dominance Relationships ◽  
New Alleles

The inheritance of leaf markings in subterranean clover (Trifolium subterraneum ssp. subterraneurn) was studied in diallel cross involving a parental genotype without a leaf marking and eleven others, each with a distinctive marking. The results indicate Mendelian inheritance, and each marking appeared to be controlled by a different allele at a single locus. An alternative interpretation of the segregation data might be that the leaf mark locus is complex and comprises many tightly linked genes. Four types of dominance were manifest in the heterozygous combinations, including one that has not previously been described. With the exception of a completely dominant allele, the dominance relationships among the other alleles could not be predicted. In one cross, the expression of one of the leaf mark alleles was partially modified, and this could be attributed to an independent recessive gene. Mutation appears to be the sole genetic mechanism by which new alleles arise. Their origin and evolution in subterranean clover is discussed with reference to Fisher's theory on the evolution of dominance.

Flowering time in subterranean clover

1956 ◽  
Vol 7 (5) ◽  
pp. 388 ◽  
Author(s):  
FHW Morley ◽  
CI Davern
Keyword(s):  
Plant Breeding ◽  
Flowering Time ◽  
Natural Habitat ◽  
Strain Differences ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Relative Importance

Genotype-environment interactions have been observed in the flowering times of a number of varieties of subterranean clover (Trifolium subterraneum L.) grown in different locations. These interactions are interpreted in terms of the effects of photoperiod and temperature on flowering. Sensitivity to photoperiod may be independent of sensitivity to temperature. Flowering times of some strains, although simultaneous in one environment, may differ in another environment. This is due to variation in the relative importance of different components of the environment in controlling flowering time. These strain differences in flowering-time physiology are shown to be related to the climate of the strain's natural habitat. The importance of a knowledge of flowering physiology, and the recognition of the existence of genotype - environment interactions, are discussed in relation to plant breeding and introduction.

Evolution in sown populations of subterranean clover (Trifolium subterraneum L. ) in South Australia

1992 ◽  
Vol 43 (7) ◽  
pp. 1583 ◽  
Author(s):  
PS Cocks
Keyword(s):  
Natural Selection ◽  
Flowering Time ◽  
Mediterranean Basin ◽  
South Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Sole Source ◽  
Selection For ◽  
The Mediterranean ◽  
The Mediterranean Basin

The seed banks of three pastures at Kingscote, Parndana and Waterloo, S.A., were sampled to determine the frequency of divergent genotypes in subterranean clover, and the direction of natural selection. The seeds were grown in nursery rows at Adelaide, and the resulting plants classified into one of the commercial cultivars, or as divergent genotypes. The divergent genotypes from one locality, Kingscote, were described in terms of 17 variables, and compared with strains collected from southern Australia and the Mediterranean basin. At each locality there was more genetic diversity than had been sown, both in terms of additional cultivars and the presence of divergent genotypes. The percentage of divergent genotypes appeared to be proportional to the age of the pasture, and was greatest at Kingscote, where it reached 67% of the population. The Kingscote genotypes were genetically related to Mt Barker and Dwalganup, only five out of 283 genotypes having leaf markings that differed from both cultivars. The 17 variables fell between the values recorded for Mt Barker and Dwalganup, and there was evidence of directional selection. For example, formononetin content was less, and genistein more than would be expected in the absence of natural selection. Mean flowering time was about equal to that of Seaton Park, and closer to Mt Barker than to Dwalganup. Flowering time was related to elevation above the lowest point in the paddock, the latest genotypes tending to inhabit sites at the foots of slopes, and the earliest genotypes sites on the tops. Seed and burr weight were slightly larger than expected. Hybridization was the most important, but not the sole source of genetic divergence at Kingscote, whereas contamination was the main source at Waterloo. It is likely that only a minority of the divergent genotypes was generated by mutation. The Australian subterranean clovers were as diverse as those from the Mediterranean. Those from Kingscote were also diverse, but, on the whole, had longer peduncles, shorter internodes and were taller than strains from other parts of Australia and from the Mediterranean basin.

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

1980 ◽  
Vol 31 (5) ◽  
pp. 927 ◽  
Author(s):  
PE Beale ◽  
N Thurling
Keyword(s):  
Trifolium Subterraneum ◽  
Diallel Analysis ◽  
Diallel Cross ◽  
Disease Development ◽  
Disease Score ◽  
Complete Diallel Cross ◽  
Disease Rating ◽  
Additive Gene ◽  
Efficient Breeding ◽  
Analysis Of Variation

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.

Effect of cultivar and grazing intensity in spring on shear and compression energies of dry mature subterranean clover (Trifolium subterraneum L.)

1997 ◽  
Vol 48 (8) ◽  
pp. 1199 ◽  
Author(s):  
Y. J. Ru ◽  
J. A. Fortune
Keyword(s):  
Flowering Time ◽  
Large Range ◽  
Grazing Intensity ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Plant Materials ◽  
Leaf Petiole ◽  
Dry Matter Digestibility ◽  
Highly Correlated ◽  
Shear Energy

Twenty-six cultivars of subterranean clover were divided into 3 maturity groups according to the flowering time and sown in 2 blocks with 4 replicates. The plots were grazed under 2 intensities (hard and lax) during the growing season. The proportions of leaf, petiole, stem, and burr before senescence, dry matter digestibility (DMD), herbage availability, and seed yield in summer were measured. The energies required to shear and compress the resultant dry mature plant materials were determined using an Instron material testing instrument. The results showed a large range for shear (11·3-18·2 kJ/m2) and compression energies (2·8-4·6 kJ/kg DM) among the 26 cultivars. Grazing intensity in spring did not affect shear energy (P > 0·05) but increased the compression energy of dry mature subterranean clover by 0·2 units (P < 0·05). The energy required to shear or compress plant materials was highly correlated with herbage availability, flowering time, proportions of leaf and petiole in the sward, and fibre content of the plant materials, with the relationships being modified by grazing intensity in spring. Compression energy was related to DMD of plants (r = -0·7) and shear energy did not account for a significant amount of variation in DMD.

Diallel Analysis of Genetic Variation in Pigeon Pea (Cajanus cajan)

1977 ◽  
Vol 13 (2) ◽  
pp. 193-200 ◽  
Author(s):  
B. S. Dahiya ◽  
J. S. Brar
Keyword(s):  
Flowering Time ◽  
Cajanus Cajan ◽  
Seed Weight ◽  
Diallel Analysis ◽  
Diallel Cross ◽  
Pigeon Pea ◽  
Graphical Analysis ◽  
Variance Component Analysis ◽  
100 Seed Weight ◽  
Pod Number

SUMMARYA diallel analysis of flowering time, pod number, 100-seed weight and yield of six cultivars of Cajanus cajan (L.) Millsp. was studied. Additive inheritance was important in determining flowering time, but the dominance component was higher than the additive component, and over-dominance was observed for pod number, 100-seed weight and yield. Heritability estimates for all the traits except flowering time were quite low, and the bulk population method of breeding was suggested for early segregating generations. The graphical analysis of the diallel cross was in close agreement with the findings from variance component analysis. It is suggested that the best cross would be that between two parents chosen on the basis of their low g.c.a. for flowering time and their high g.c.a. for other traits.

COMBINING ABILITY FOR INHERITANCE OF ECONOMIC TRAITS IN OPIUM POPPY (Papaver somniferum L.)

2011 ◽  
Vol 24 (2) ◽  
pp. 01-08
Author(s):  
B. Kumar ◽  
N. K. Patra
Keyword(s):  
Combining Ability ◽  
Diallel Cross ◽  
Papaver Somniferum ◽  
Opium Poppy ◽  
Economic Traits ◽  
Degree Of Dominance ◽  
Parental Material ◽  
The Mean ◽  
Per Se ◽  
Important Medicinal Plant

Opium poppy (Papaver somniferum L.) is an important medicinal plant produces more than 80 alkaloids obtained from the capsules and straw of the plant. The estimate of combining ability gives an indication of the genetic behaviour of the parental material. It is therefore, desirable to select the parents for hybridization on the basis of their per se performance and combining ability effects. The F1, F2 and their reciprocals of an eight parent diallel cross in opium poppy were studied for combining ability of seven economic traits. The mean sum of squares due to GCA, SCA and reciprocals were significant for all the traits. The magnitude of GCA variances were invariably higher than those of SCA and thus indicating the preponderance of non-additive genetic variances, which was further affirmed by the measure of average degree of dominance i.e. ?(?2s/? 2g).  Among the parents VN35I for plant height, Sanchita and VG26 for capsules per plant, VN23, VN35I and Vivek for capsule index, VG26 and Sanchita for seed and straw yield per plant, and VN35I and VG20 for morphine content were found good general combiners. Earliness being a desired trait, parent VG20 having significant negative GCA estimates coupled with per se performance can be considered as good general combiner for early flowering. Inclusion of good general combiners in a multiple crossing program or an inter-mating population involving all possible crosses among them subjected to bi-parental mating may be expected to offer maximum promise in breeding for economic traits.DOI: http://dx.doi.org/10.3329/bjpbg.v24i2.17000

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