Response to divergent selection for early vigour in sunflower (Helianthus annuus L.)

Early vigour (EV), biomass at the first development stages, may be a positive trait to improve sunflower yield in water-limited environments. Field experiments were carried out from 1992 to 1995 to define an index to quantify EV in sunflower plants, evaluate the response to divergent selection for this trait, study EV ×environment interaction, estimate the heritability of EV, and study the association of EV with other traits. A sunflower population with a broad genetic base and 10 sunflower lines derived from it were used. Stem volume calculated from stem diameter and height measured approximately 425 degree-days after emergence was correlated with above-ground plant biomass at the same date. In 1992, divergent selection for high and low stem volume was carried out on this population and plants from every group were recombined independently, obtaining 2 new populations. Selection response, using these and the initial population, was studied in 1993. Ten S2 lines, 5 with high-EV derived from the high-EV population and 5 with low-EV derived from the low EV population, were sown in 1995 to study the EV ×environment interaction. Differences among lines with different EV were significant in all the environments studied. In 1993, a random sample from the initial population was selfed and broad sense heritability and heritability by parent-offspring regression were estimated. Heritability based on variance component estimates of S1 progeny means was 0·61. Realised heritability (± s.e.) from a divergent selection for high and low stem volume were 0·40±0·10 and 0·52±0·15, respectively. Heritability by parent-offspring regression was 0· 40± 0·10. These values and the high variability of stem volume observed in the new populations indicate that additional gain from selection should be possible.

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Genetic improvement of early vigour in wheat

Australian Journal of Agricultural Research ◽

10.1071/a98125 ◽

1999 ◽

Vol 50 (3) ◽

pp. 291 ◽

Cited By ~ 146

Author(s):

G. J. Rebetzke ◽

R. A. Richards

Keyword(s):

Genetic Variation ◽

Leaf Area ◽

Plant Biomass ◽

Genetic Correlations ◽

Yield Potential ◽

Environment Interaction ◽

Narrow Sense Heritability ◽

Wheat Varieties ◽

Early Vigour ◽

Selection For

Grain yield potential of Australian wheat crops is often limited because of inadequate water for crop growth and grain filling. Greater early vigour, defined here as the amount of leaf area produced early in the season, should improve the water-use efficiency and yield of wheat crops grown in Mediterranean-type climates such as occurs in southern Australia. In order to maximise selection efficiency for early vigour in breeding programs, the magnitude and form of genetic variation for early vigour and its components was investigated for 2 contrasting wheat populations. The first population comprised 28 Australian and overseas wheat varieties evaluated in a serial sowing study in Canberra. The second population contained 50 random F 2:4 and F 2:6 families derived from a convergent cross of elite CIMMYT wheat lines evaluated in Canberra, and in the field at Condobolin, New South Wales. For the first population, environmental effects on leaf breadth and length, and to a lesser extent, phyllochron interval, produced significant (P < 0.05) changes in leaf area. Large and significant (P < 0.05) differences were observed among Australian and overseas wheats for early vigour and its components. Australian varieties were among the least vigorous of the lines tested, with a number of overseas varieties producing about 75% greater leaf area than representative Australian wheats. Increased leaf area was genetically correlated with increases in leaf breadth and length, and a longer phyllochron interval. Significant (P < 0.05) genotype ´ environment interaction reduced broad-sense heritability (%) for early vigour (H ± s.e., 87 ± 26) compared with leaf breadth (96 ± 25) and length (97 ± 27). Narrow-sense heritability (%) in the second population was small for leaf area (h2 ± s.e., 30 ± 6) and plant biomass (35 ± 7), but high for leaf breadth (76 ± 14) and length (67 ± 16). Genetic correlations were strong and positive for leaf area with plant biomass, leaf breadth and length, specific leaf area and coleoptile tiller frequency, whereas faster leaf and primary tiller production were negatively correlated with leaf area. The high heritability for leaf breadth coupled with its strong genetic correlation with leaf area (rg = 0.56-0.57) indicated that selection for leaf breadth should produce genetic gain in leaf area similar to selection for leaf area per se. However, the ease with which leaf breadth can be measured indicates that selection for this character either by itself, or in combination with coleoptile tiller production, should provide a rapid and non-destructive screening for early vigour in segregating wheat populations. The availability of genetic variation for early vigour and correlated traits should enable direct or indirect selection for greater leaf area in segregating wheat populations.

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Divergent selection for fat index in Pannon Ka rabbits: genetic parameters, selection response

World Rabbit Science ◽

10.4995/wrs.2020.12733 ◽

2020 ◽

Vol 28 (3) ◽

pp. 129

Author(s):

R. Kasza ◽

ZS. Matics ◽

ZS. Gerencsér ◽

T. Donkó ◽

I. Radnai ◽

...

Keyword(s):

Body Fat ◽

Heritability Estimate ◽

Selection Response ◽

Divergent Selection ◽

The Body ◽

Total Body Fat ◽

Parent Groups ◽

Selection For ◽

Total Body ◽

Zero Generation

<p>The objective of this study was to estimate the response to selection for total body fat content of rabbits measured by computer tomography (CT). A divergent selection experiment was performed using Pannon Ka rabbits, which were previously selected for number of kits born alive. The so-called zero generation consisted of 351 Pannon Ka rabbits, from which the index, total body fat volume (cm<sup>3</sup>) divided by the body weight (kg), was measured. Rabbits with low and high fat index values were selected to form the parent groups of the lean and fat lines, respectively. The lines consisted of 55-72 females and 35-47 males, depending on the line and generation. After three generations, the rabbits were evaluated by means of a single trait animal model. The fat index showed a moderate heritability estimate (0.28±0.03). The magnitude of the common litter effect was small (0.10±0.02). The breeding values averaged per generation provided slightly asymmetrical responses. Based on the results, the divergent selection was successful in confirming that CT is a very suitable method for performing selection for body composition traits.</p>

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Response in Genotypic and Breeding Value to a Single Generation of Divergent Selection for Fresh Fruit Color in Strawberry

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.120.2.270 ◽

1995 ◽

Vol 120 (2) ◽

pp. 270-273 ◽

Cited By ~ 5

Author(s):

Douglas V. Shaw ◽

Erik J. Sacks

Keyword(s):

Genetic Variance ◽

Breeding Population ◽

Selection Response ◽

Fruit Color ◽

Divergent Selection ◽

Fresh Fruit ◽

Breeding Value ◽

Genetic Variances ◽

Selection For ◽

Genotypic Selection

Four sets of selected strawberry (Fragaria ×ananassa Duch.) genotypes were generated from within a single breeding population to evaluate the correspondence between predicted and realized selection response for fresh fruit color traits. Genotypes were selected for extreme phenotypes, dark or light, of either internal or external color value (CIELAB L*). Genotypic selection response was evaluated empirically by scoring fruit from the clonal derivatives of these selected genotypes, and response for breeding value was estimated by scoring the offspring of crosses performed among a subset of the genotypes within each selected set. Realized selection response was slightly larger than predicted for internal and external L* when calculated for selected genotypes. Also, more than half of the selected genotypes had genotypic values for L* outside the range of the original parents, providing evidence for transgressive segregation. Realized selection response for breeding value in exterior and interior color was slightly less than predicted. Compared in a different way, genotypic selection response for external color was significantly greater than selection response for breeding value, whereas genotypic and breeding value responses did not differ for internal color. These observations suggest the presence of some nonadditive genetic variance for external color but support the conclusion that the heritabilities predicted previously were reasonably accurate. Estimates of variance components within each of the offspring populations demonstrated that genetic variances were modified substantially by one generation of selection. Selection for dark fruit color reduced genetic variance to nonsignificant levels, with internal color more affected than external color. The total genetic variances within both of the offspring populations from parents selected for light color were changed little by one generation of selection, but substantial dominance variance was detected that had not been found in the original population. The rapid response to selection and large changes in the distribution of genetic variances may indicate the presence of a few genes with comparatively large effect in strawberry color expression. Additional divergent selection response can be expected, but primarily in the direction of light fruit color.

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Flower colour adaptation in a mimetic orchid

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2011.2375 ◽

2012 ◽

Vol 279 (1737) ◽

pp. 2309-2313 ◽

Cited By ~ 66

Author(s):

Ethan Newman ◽

Bruce Anderson ◽

Steven D. Johnson

Keyword(s):

Flower Colour ◽

Adaptive Significance ◽

Divergent Selection ◽

Floral Colour ◽

Environment Interaction ◽

Colour Preference ◽

The West ◽

Reciprocal Translocations ◽

Selection For ◽

Artificial Flowers

Although the tremendous variability in floral colour among angiosperms is often attributed to divergent selection by pollinators, it is usually difficult to preclude the possibility that floral colour shifts were driven by non-pollinator processes. Here, we examine the adaptive significance of flower colour in Disa ferruginea , a non-rewarding orchid that is thought to attract its butterfly pollinator by mimicking the flowers of sympatric nectar-producing species. Disa ferruginea has red flowers in the western part of its range and orange flowers in the eastern part—a colour shift that we hypothesized to be the outcome of selection for resemblance to different local nectar-producing plants. Using reciprocal translocations of red and orange phenotypes as well as arrays of artificial flowers, we found that the butterfly Aeropetes tulbaghia , the only pollinator of the orchid, preferred both the red phenotype and red artificial flowers in the west where its main nectar plant also has red flowers, and both the orange phenotype and orange artificial flowers in the east, where its main nectar plant has orange flowers. This phenotype by environment interaction demonstrates that the flower colour shift in D. ferruginea is adaptive and driven by local colour preference in its pollinator.

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SELECTION RESPONSE FOR INCREASED GRAIN YIELD IN TWO HIGH OIL MAIZE SYNTHETICS

Indonesian Journal of Agricultural Science ◽

10.21082/ijas.v8n1.2007.p1-9 ◽

2016 ◽

Vol 8 (1) ◽

pp. 1

Author(s):

Made J. Mejaya ◽

R.J. Lambert

Keyword(s):

Grain Yield ◽

Yield Components ◽

Field Experiments ◽

Selection Response ◽

Kernel Weight ◽

Grain Weight ◽

Kernel Number ◽

Starch Concentration ◽

Oil Concentration ◽

Selection For

Selection for increased oil level in maize showed the increase was associated with decrease in starch concentration, kernel weight, and grain yield. The study was conducted with the objectives: (1) to evaluate response to six cycles for increased grain yield in the high oil maize Alexho Elite (AE: 60-90 g kg-1 oil concentration) and Ultra High Oil (UHO: 100-140 g kg-1 oil concentration) using inbred tester B73; (2) to measure responses to selection for increased grain yield with changes in yield components; and (3) to determine a suitable tester. Previously the two synthetics had been selected for oil concentration. After six cycles, the six genotypes i.e. AE C0, AE C3, AE C6, UHO C0, UHO C3, and UHO C6 were testcrossed to B73, LH185, and LH202 inbreds (40 g kg-1 oil concentration) to a total of 18 testcrosses. Two field experiments were used to evaluate selection in AE and UHO testcrosses. The study showed selection using inbred tester B73 in AE and UHO was effective in increasing grain yield of AE testcrosses without changing (i.e. decreasing) oil and protein concentrations. AE testcrosses produced higher grain yield and greater selection response for grain yield than UHO testcrosses. LH185 was best for grain yield in AE and UHO testcrosses. Increase in grain yield in most of the testcrosses was associated with increases in starch concentration, kernel weight, kernel number, and grain weight.

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SELECTION RESPONSE FOR INCREASED GRAIN YIELD IN TWO HIGH OIL MAIZE SYNTHETICS

Indonesian Journal of Agricultural Science ◽

10.21082/ijas.v8n1.2007.1-9 ◽

2016 ◽

Vol 8 (1) ◽

pp. 1

Author(s):

Made J. Mejaya ◽

R.J. Lambert

Keyword(s):

Grain Yield ◽

Yield Components ◽

Field Experiments ◽

Selection Response ◽

Kernel Weight ◽

Grain Weight ◽

Kernel Number ◽

Starch Concentration ◽

Oil Concentration ◽

Selection For

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ESTIMASI NILAI HERITABILITAS BOBOT IKAN MAS VARIETAS PUNTEN DALAM PROGRAM SELEKSI INDIVIDU

Jurnal Riset Akuakultur ◽

10.15578/jra.11.3.2016.217-223 ◽

2016 ◽

Vol 11 (3) ◽

pp. 217

Author(s):

Estu Nugroho ◽

Budi Setyono ◽

Mochammad Su’eb ◽

Tri Heru Prihadi

Keyword(s):

Body Weight ◽

Selection Response ◽

Base Population ◽

Breeding Programs ◽

Male And Female ◽

Body Weight Trait ◽

Population Selection ◽

Selection For ◽

Weight Trait ◽

Selection Of

Program pemuliaan ikan mas varietas Punten dilakukan dengan seleksi individu terhadap karakter bobot ikan. Pembentukan populasi dasar untuk kegiatan seleksi dilakukan dengan memijahkan secara massal induk ikan mas yang terdiri atas 20 induk betina dan 21 induk jantan yang dikoleksi dari daerah Punten, Kepanjen (delapan betina dan enam jantan), Kediri (tujuh betina dan 12 jantan), Sragen (27 betina dan 10 jantan), dan Blitar (15 betina dan 11 jantan). Larva umur 10 hari dipelihara selama empat bulan. Selanjutnya dilakukan penjarangan sebesar 50% dan benih dipelihara selama 14 bulan untuk dilakukan seleksi dengan panduan hasil sampling 250 ekor individu setiap populasi. Seleksi terhadap calon induk dilakukan saat umur 18 bulan pada populasi jantan dan betina secara terpisah dengan memilih berdasarkan 10% bobot ikan yang terbaik. Calon induk yang terseleksi kemudian dipelihara hingga matang gonad, kemudian dipilih sebanyak 150 pasang dan dipijahkan secara massal. Didapatkan respons positif dari hasil seleksi berdasarkan bobot ikan, yaitu 49,89 g atau 3,66% (populasi ikan jantan) dan 168,47 g atau 11,43% (populasi ikan betina). Nilai heritabilitas untuk bobot ikan adalah 0,238 (jantan) dan 0,505 (betina).Punten carp breeding programs were carried out by individual selection for body weight trait. The base population for selection activities were conducted by mass breeding of parent consisted of 20 female and 21 male collected from area Punten, eight female and six male (Kepanjen), seven female and 12 male (Kediri), 27 female and 10 male (Sragen), 15 female and 11 male (Blitar). Larvae 10 days old reared for four moths. Then after spacing out 50% of total harvest, the offspring reared for 14 months for selection activity based on the sampling of 250 individual each population. Selection of broodstock candidates performed since 18 months age on male and female populations separately by selecting based on 10% of fish with best body weight. Candidates selected broodstocks were then maintained until mature. In oder to produce the next generation 150 pairs were sets and held for mass spawning. The results revealed that selection response were positive, 49.89 g (3.66%) for male and 168.47 (11.43%) for female. Heritability for body weight is 0.238 (male) and 0.505 (female).

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