A diallel cross in black spruce

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 180-186 ◽  
Author(s):  
T. J. B. Boyle
Keyword(s):  
Combining Ability ◽  
Variance Components ◽  
Genetic Variance ◽  
Black Spruce ◽  
Diallel Cross ◽  
Specific Combining Ability ◽  
Environment Interaction ◽  
Forest Genetics ◽  
Data Set ◽  
Dominance Genetic Variance

A complete 7 × 7 diallel of black spruce (Picea mariana (Mill.) B.S.P.), without selfs, planted in three locations, was measured for height growth at several ages. Analysis using Griffing's method 3, model II, demonstrated that general combining ability (GCA) was the dominant genetic component of variation, although specific combining ability (SCA) appeared to be proportionately increasing in importance with age. When data from all locations were combined, the GCA × environment interaction proved to be highly significant. If the trend of increasing proportional importance of SCA continues, existing improvement strategies exploiting only GCA may need to be radically altered. Greater genetic gain would result from crosses among a few clones of high specific combining ability. Whatever approach is used, it appears likely that genotypes will have to be carefully matched to sites. Imbalance in the data set appeared to invalidate F-tests. As a result of heterozygosity in the parents and the likely presence of epistasis and linkage disequilibrium, the interpretation of GCA and SCA variance components in terms of additive and dominance genetic variance cannot be made. Key words: diallel cross, combining ability, black spruce, forest genetics.

scholarly journals Genetic analysis and clonal stability of two yellow cypress clonal populations in British Columbia

2013 ◽  
Vol 62 (1-6) ◽  
pp. 173-186 ◽  
Author(s):  
B. S. Baltunis ◽  
J. H. Russell ◽  
A.Van Niejenhuis ◽  
J. Barker ◽  
Y. A. El-Kassaby
Keyword(s):  
British Columbia ◽  
Genetic Analysis ◽  
Combining Ability ◽  
Variance Components ◽  
Genetic Variance ◽  
Genetic Correlations ◽  
Specific Combining Ability ◽  
Type B ◽  
Height Range ◽  
Coastal British Columbia

AbstractGenetic analysis of height and form at age 12 years of 697 yellow cypress (Callitropsis nootkatensis [D. Don] Oerst.) clones tested across seven sites in coastal British Columbia (BC) were explored in populations: Population 1 - No Pedigree and Population 2 - Reconstructed Pedigree. Genetic variances were statistically significant but generally higher σ̂g2was observed for Population 2. Height and form were under low to moderate genetic control as indicated by clonal repeatability and estimates were relatively similar between populations. For example, average Ĥ2in Population 2 was 0.31 for height (range: 0.18-0.45) and 0.22 for form (range: 0.06-0.32). While average Ĥ2in Population 1 was 0.25 for height (range: 0.19-0.35) and 0.18 for form (range: 0.09-0.27). The reconstructed pedigree in Population 2 allowed partitioning the genetic variance (σ̂g2) into component parts of additive (σ̂a2), specific combining ability (σ̂s2), and clone (σ̂c2); however, general lack of structure within the population resulted in variance components to be estimated with little precision for additive and specific combining ability. The majority of genetic variation was associated with clone for both traits. For example, σ̂c2accounted for 57.6% and 62.5% of the total genetic variance for height and form, respectively. Growth and form responses of clones across test environments were relatively stable and overall type-B genetic correlations were in excess of 0.8 for both traits implying clones selected for production populations should respond favorably across the seed planning zone for yellow cypress in coastal BC.

HETEROSIS, COMBINING ABILITY, AND PREDICTED SYNTHETICS FROM A DIALLEL CROSS IN SUNFLOWERS (HELIANTHUS ANNUUS L.)

1966 ◽  
Vol 46 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Eric D. Putt
Keyword(s):  
Helianthus Annuus ◽  
Combining Ability ◽  
Oil Content ◽  
Diallel Cross ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Helianthus Annuus L ◽  
The Mean ◽  
Seed Characters ◽  
Mature Weight

Heterosis occurred for the eight plant and seed characters studied. It was most frequent for yield of seed and height of plant. Mean squares for general combining ability (gca) and specific combining ability (sca) were significant (P =.01) for all characters. The estimated components for gca were greater than for sca for days to mature, weight per bushel, and percent oil in the seed; less for height and yield of seed; and essentially the same for days to bloom, diameter of head, and weight per 1000 seeds.The yield of seed and percent oil in the seed, for the highest ranking 100 synthetics that could be composed from the 10 lines, was predicted in F6 assuming 50 and 60% outcrossing between F2 and F6. Virtually all values exceeded the mean performance of four check samples of commercial hybrids. Many exceeded the highest rank check for oil content in the seed. Fourteen of the highest ranking 100 synthetics for yield and 30 for oil content consisted of two or three lines. It was concluded that synthetics can be superior to the present hybrids in heterosis and that desirable synthetics can be made from only a few lines.

scholarly journals Performance of testers with different genetic structure for evaluation of maize inbred lines

2012 ◽  
Vol 42 (5) ◽  
pp. 770-776 ◽  
Author(s):  
Lauro José Moreira Guimarães ◽  
Glauco Vieira Miranda ◽  
Rodrigo Oliveira DeLima ◽  
Ciro Maia ◽  
Lucimar Rodrigues de Oliveira ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Combining Ability ◽  
Genetic Variance ◽  
Inbred Lines ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Genetic Base ◽  
Maize Inbred Lines ◽  
Single Cross ◽  
Single Cross Hybrids

The objective of this study was to evaluate four maize testers for identification of superior inbreed lines in testcross. The four testers evaluated are cultivars with narrow or wide genetic base (single-cross hybrids and open pollinated varieties) and two kernel types (flint or dent). SynD and SynF testers are open pollinated varieties with dent and flint kernels, respectively, and FSH and DSH testers are single-cross hybrids with flint and dent kernels, respectively. SynD tester showed the biggest genetic variance among the maize inbreed lines in crosses. The effects of general combining ability (GCA) for lines and specific combining ability (SCA) for lines x testers were significant, whereas GCA effects for testers were not significant. SynD and SynF testers identified the largest number of lines with higher GCA. The DSH and FSH testers showed suitable to identify lines with high SCA. It was concluded that SynD and SynF testers are adequate to identify inbreed lines with high GCA effects, and it's possible to identify new lines with high heterotic potential in each one of the four testers.

Studies on Combining Ability for Seed Yield and Its Related Traits in Blackgram [Vigna mungo (L.) Hepper]

2020 ◽  
Author(s):  
Ranjana Patial ◽  
R. K. Mittal ◽  
V. K. Sood ◽  
Shahnawaz Ahmed
Keyword(s):  
Seed Yield ◽  
Combining Ability ◽  
Genetic Variance ◽  
Gene Action ◽  
Specific Combining Ability ◽  
Breeding Programme ◽  
Plant Seed ◽  
Ability Estimates ◽  
Additive Gene ◽  
Transgressive Segregants

An experiment was carried out in blackgram using line x tester mating design to estimate the GCA effect of parents and SCA effect of 54 hybrids for yield and its traits using 27 lines and two testers. The relative estimates of variance due to specific combining ability (SCA) were higher than general combining ability (GCA) variances for all twelve traits, indicating predominance of non-additive gene action. Combining ability estimates showed significant genetic variance in lines for all traits whereas testers had significant genetic variance for nine traits. On the basis of GCA effects, among the lines and testers IC-436910, IC-413306, IC-398973, IC-343885 and HPBU-111 respectively, were good combiners for most of the traits and can be used in future breeding programme. Specific combining ability studies indicated cross IC-436910 x HPBU-111 as best specific combiner for the economically important traits viz., plant height, branches per plant, seed yield per plant and days to 75% maturity. Such crosses could be further exploited to obtain transgressive segregants in future breeding programme.

Quantitative inheritance studies in sugar-cane. I. Estimation of variance components

1971 ◽  
Vol 22 (1) ◽  
pp. 93 ◽  
Author(s):  
DM Hogarth
Keyword(s):  
Factorial Design ◽  
Variance Components ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
The Other ◽  
Quantitative Inheritance ◽  
Genetic Determination ◽  
Nested Design ◽  
Dominance Genetic Variance ◽  
Estimation Of Variance

Two experiments in quantitative genetics were conducted, one based on a nested design in lattice squares and the other on a factorial design in a balanced lattice. Lattice designs were found to be suitable for genetic experiments if a large number of crosses was involved, but posed some problems in partitioning the sum of squares for treatments. The factorial design was considered preferable to the nested design, although neither design permitted estimation of epistatic variances which, therefore, were assumed to be negligible. Additive genetic variance was found to be more important than dominance genetic variance for most characters. However, most estimates of genetic variance lacked precision in spite of the use of large, precise experiments, which illustrated the difficulty in obtaining estimates of variance components with adequate precision. The validity of assumptions made for these analyses is discussed. The effect of competition was studied and estimates of heritability and degree of genetic determination were determined.

GENERAL AND SPECIFIC COMBINING ABILITY IN SEVEN INBRED STRAWBERRY LINES

1968 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Lewis E. Aalders ◽  
Donald L. Craig
Keyword(s):  
Genetic Variation ◽  
Powdery Mildew ◽  
Combining Ability ◽  
Diallel Cross ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Additive Genetic Variation

Seedlings of a diallel cross of seven strawberry inbreds omitting reciprocals were fruited in matted rows. Per acre fruit yields were comparable with leading cultivars, but berry appearance and quality of the hybrids were poor. Differences in resistance to powdery mildew reflected the values of the cultivars from which the inbreds were derived.All four characters studied showed significant general combining ability values, and three of the four showed significant specific combining ability values. These results are consistent with previous findings of considerable amounts of non-additive genetic variation in the strawberry.

COMBINING ABILITY FOR YIELD OF SYNTHETIC HEXAPLOID WHEATS

1974 ◽  
Vol 54 (2) ◽  
pp. 235-239 ◽  
Author(s):  
R. J. BAKER ◽  
P. L. DYCK
Keyword(s):  
Triticum Aestivum ◽  
Seed Yield ◽  
Combining Ability ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Triticum Aestivum L ◽  
Kernel Weight ◽  
Specific Combining Ability ◽  
Synthetic Hexaploid Wheats ◽  
Synthetic Hexaploid

Four hexaploid spring wheats (Triticum aestivum L.), which differ only in their D genomes, were crossed in all combinations. Heterosis was expressed in F1 and F2 for number of spikes, kernel weight, and seed yield. Failure to detect significant specific combining ability among F1 progeny suggests that only additive genetic variance is involved in the inheritance of these traits. Competition between single-spaced plants was detected.

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