scholarly journals Genetic variation and response to selection for storage root dry matter and associated traits in a population of yam bean (Pachyrhizus spp.) interspecies crosses

Euphytica ◽  
2021 ◽  
Vol 217 (4) ◽  
Author(s):  
Rolland Agaba ◽  
Patrick Rubaihayo ◽  
Phinehas Tukamuhabwa ◽  
Robert O. M. Mwanga ◽  
Silver Tumwegamire ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Coefficient Of Variation ◽  
Dry Matter ◽  
Block Design ◽  
Genetic Correlations ◽  
Storage Root ◽  
Response To Selection ◽  
Genetic Progress ◽  
Narrow Sense Heritability ◽  
High Dry Matter

AbstractThe goal of yam bean improvement in Africa is to develop superior high yielding and high dry matter cultivars that are preferred for adoption. In this study, the estimates of variance components, heritability and response to selection were studied in F3 yam bean families selected from interspecies crosses targeting improvement of storage root dry matter and associated traits. Breeding populations were generated using North Carolina II (NC II) mating design involving high dry matter P. tuberosus chuin cultivar, low dry matter P. ahipa and the high yielding P. erosus yam beans. The progenies were advanced through selfing from F1 to F2 population and then exposed to selection at 10% selection intensity to obtain 83 high dry matter lines. The selected lines were evaluated in an F3 trial using a randomized complete block design (RCBD) with three replications at the National Crops Resources Research Institute (NaCRRI) Namulonge, in Central Uganda. The results revealed significant (P < 0.001) genetic variation for storage root dry matter (RDM), storage root fresh yield (RFY), storage root dry yield (RDY), vine yield (VNY), fresh biomass yield (FBY), harvest index (HI), starch (STA) and protein (PRO) content. High genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were obtained for VNY, RDY, FBY, RFY, RDM and STA. Narrow sense heritability was higher than 0.5 and response to selection was 15.5 to 33.1 for RDM, RFY, RDY, VNY, FBY and STA, indicating rapid genetic progress is achievable and early generation selection would be effective to improve these traits. Significant (P < 0.01) positive genetic correlations were observed between RDM, RDY, RFY, VNY, FBY and STA ranging from 0.422 to 0.963 implying that simultaneous improvement of these traits is possible in the current yam bean populations.

scholarly journals Genetic Variability for Yield and Nutritional Quality in Yam Bean (Pachyrhizus sp.)

HortScience ◽  
2016 ◽  
Vol 51 (9) ◽  
pp. 1079-1086 ◽  
Author(s):  
Rolland Agaba ◽  
Phinehas Tukamuhabwa ◽  
Patrick Rubaihayo ◽  
Silver Tumwegamire ◽  
Andrew Ssenyonjo ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Dry Matter ◽  
Dry Matter Content ◽  
Quality Traits ◽  
Storage Root ◽  
Storage Roots ◽  
High Dry Matter ◽  
Yield And Quality ◽  
Coefficients Of Variation

The amount of genotypic and phenotypic variability that exists in a species is important for selection and initiating breeding programs. Yam bean is grown locally in tropical countries of the Americas and Asia for their tasty storage roots, which usually have low dry matter content. The crop was recently introduced in Uganda and other East and Central African countries to supplement iron (Fe) and protein content in diets. This study aimed to estimate genetic variability for root yield and quality traits among 26 yam bean accessions in Uganda. A randomized complete block design was used with two replications across two ecogeographical locations and two seasons during 2012 and 2013. Near-infrared reflectance spectroscopy (NIRS) was used to determine quality of storage root samples. Significant differences among genotypes were observed for all traits except root protein, zinc (Zn), and phosphorus contents. Genotypic variance components () were significant for storage root fresh yield (SRFY), storage root dry matter (SRDM), storage root dry yield (SRDY), vine yield (VNY), fresh biomass yield (FBY), and storage root starch (STA) and Fe contents. For traits with significant the broad sense heritability estimates ranged from 58.4% for SRDY to 83.6% for FBY; and phenotypic coefficients of variation were high for SRFY (66%), SRDY (53.3%), VNY (60.5%), and FBY (59%), but low to medium for SRDM (22.6%), STA (15.1%), and Fe (21.3%). Similarly, the genotypic coefficients of variation were high for SRFY (56.7%), SRDY (53.3%), VNY (55%), and FBY (53.9%); and low for SRDM (20%), STA (12.4%), and Fe (17.8%). There were strong positive correlations between SRFY and both SRDY (r = 0.926) and FBY (r = 0.962), but low-to-moderate correlations among quality traits. It should be possible to breed for high dry matter yam beans by using low dry matter accessions due to the observed genetic variation ( = 9.3%2), which is important if the high dry matter Pachyrhizus tuberosus accessions (known as chuin) from Peru cannot be accessed. This study indicated substantial genetic variation for yield and quality traits in yam bean, demonstrating potential for adaptability to growing conditions and consumer needs in East and Central Africa and for genetic improvement through selection.

scholarly journals Genetic variation among and within provenances and progenies of Corymbia maculata (Hook.) K. D. Hill and L. A. S. Johnson, in Pederneiras, SP

CERNE ◽  
2010 ◽  
Vol 16 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Aida Sanae Sato ◽  
Miguel Luiz Menezes Freitas ◽  
Israel Luiz de Lima ◽  
Léo Zimback ◽  
Maria Teresa Zugliani Toniato ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Block Design ◽  
Genetic Correlations ◽  
Genetic Progress ◽  
Straight Line ◽  
Outer Border ◽  
High Selection ◽  
Eucalyptus Maculata ◽  
Coefficient Of Genetic Variation ◽  
Selection Of

This study aimed to estimate genetic parameters and variation in a provenance-progeny test of C. maculata (ex Eucalyptus maculata Hook.), conducted at Pederneiras Experimental Station, in São Paulo Forest Institute. The test was based on 21 open-pollination progenies from provenance Woondum St. Forest and 17 from provenance Wondai St. Forest, both in Australia. A compact family block design was adopted consisting of ten blocks, six plants per straight-line plot and two outer border rows, with spacing 3 x 2 m. Traits assessed included diameter at breast height (DBH), height, volume, form and survival rate at age 4 and 21 years. Significant differences were detected only at age 4 between provenances for DBH and height and among progenies for DBH, height and volume. The coefficient of genetic variation was higher for all traits at age 21. The heritability coefficient at the progeny level (h m²) was also higher at age 21 and ranged from 0.21 for volume to 0.40 for height, indicating that genetic progress can be achieved through selection of the best progenies. Genetic correlations were high between traits within and between age categories, showing that potential genetic gains can be achieved through indirect, early selection. Results indicate that considerable gains can be made if high selection intensity is applied among and within progenies, with values ranging from 12.48% for height to 21.77% for volume.

scholarly journals Genetic Variation for Biomass Yield and Predicted Genetic Gain in Lowland Switchgrass “Kanlow”

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1845
Author(s):  
Santosh Nayak ◽  
Hem Bhandari ◽  
Carl Sams ◽  
Virginia Sykes ◽  
Haileab Hilafu ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Gain ◽  
Panicum Virgatum ◽  
Biomass Yield ◽  
Block Design ◽  
Perennial Grass ◽  
Warm Season ◽  
Narrow Sense ◽  
Bioenergy Feedstock ◽  
Narrow Sense Heritability

Switchgrass (Panicum virgatum L.) is a warm-season, perennial grass valued as a promising candidate species for bioenergy feedstock production. Biomass yield is the most important trait for any bioenergy feedstock. This study was focused on understanding the genetics underlying biomass yield and feedstock quality traits in a “Kanlow” population. The objectives of this study were to (i) assess genetic variation (ii) estimate the narrow sense heritability, and (iii) predict genetic gain per cycle of selection for biomass yield and the components of lignocelluloses. Fifty-four Kanlow half-sib (KHS) families along with Kanlow check were planted in a randomized complete block design with three replications at two locations in Tennessee: Knoxville and Crossville. The data were recorded for two consecutive years: 2013 and 2014. The result showed a significant genetic variation for biomass yield (p < 0.05), hemicellulose concentration (p < 0.05), and lignin concentration (p < 0.01). The narrow sense heritability estimates for biomass yield was very low (0.10), indicating a possible challenge to improve this trait. A genetic gain of 16.5% is predicted for biomass yield in each cycle of selection by recombining parental clones of 10% of superior progenies.

The genetic variation in the timing of heteroblastic transition in Eucalyptus globulus is stable across environments

2011 ◽  
Vol 59 (2) ◽  
pp. 170 ◽  
Author(s):  
M. G. Hamilton ◽  
P. A. Tilyard ◽  
D. R. Williams ◽  
R. E. Vaillancourt ◽  
T. J. Wardlaw ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Phase Change ◽  
Eucalyptus Globulus ◽  
Developmental Change ◽  
Genetic Correlations ◽  
Genotype By Environment Interaction ◽  
Environment Interaction ◽  
Narrow Sense Heritability ◽  
Genotype By Environment ◽  
Analyse Data

Eucalyptus globulus is one of the best known examples of a heteroblastic plant. It exhibits a dramatic phase change from distinctive juvenile to adult leaves, but the timing of this transition varies markedly. We examined the genetic variation in the timing of heteroblastic transition using five large open-pollinated progeny trials established in north-western Tasmania. We used univariate and multi-variate mixed models to analyse data on the presence/absence of adult or intermediate foliage at age 2 years from a total of 14 860 trees across five trials, as well as height to heteroblastic phase change from one trial. Up to 566 families and 15 geographic subraces of E. globulus were represented in the trials. The timing of the heteroblastic transition was genetically variable and under strong genetic control at the subrace and within-subrace level, with single-trial narrow-sense heritability estimates for the binary trait averaging 0.50 (range 0.44–0.65). The degree of quantitative trait differentiation in the timing of heteroblastic transition among subraces, as measured by QST, exceeded the published level of neutral molecular marker (FST) differentiation in all cases, arguing that diversifying selection has contributed to shaping broad-scale patterns of genetic differentiation. Most inter-trial genetic correlations were close to one at the subrace and additive genetic levels, indicating that the genetic variation in this important developmental change is expressed in a stable manner and that genotype-by-environment interaction is minimal across the environments studied.

scholarly journals 470 Narrow-sense Heritability Estimates for Melon Root Traits

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 475A-475
Author(s):  
Kevin M. Crosby
Keyword(s):  
Genetic Variation ◽  
Root System ◽  
Block Design ◽  
Root Systems ◽  
Root Surface ◽  
Root Tip ◽  
Root Surface Area ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Heritability Estimates

Improving melon root systems by traditional breeding is one component of the program to develop multiple-stress-resistant melons at the Texas Agricultural Experiment Station, Weslaco. Ten diverse melon lines representing four horticultural groups were intercrossed utilizing a Design II mating scheme. The male parents were: `PI 403994,' `Perlita,' `Doublon,' `Caravelle', and `PI 525106.' The female parents were: `Créme de Menthe,' `Magnum 45,' `BSK,' `PI 124111 × TDI', and `Deltex.' F1 progeny were grown in pasteurized sand in the greenhouse using a randomized complete-block design with four reps. After 4 weeks, root systems from all plants were carefully washed to remove the sand. Each root system was then placed onto a glass, plated, and scanned into the computer software Rhizo Pro 3.8 (Regent Instruments, Quebec). This software calculated root lengths of various diameter classes, root area, and root tip number. All data was input into Agrobase software for calculation of genetic variances based on Design II analysis. Significant differences of contributions by male parents to progeny variation were few. Only length of roots with 1.0- to 1.5-mm-diameter and vine length were significantly different. Differences in contributions by female parents to all traits except root tip number were highly significant. No significant interaction effects were observed for any trait. Narrow-sense heritability estimates were moderate to high for all traits. The range was from 0.56 for root tip number by males to 0.81 for both length of 0.5- to 1.0-mm-diameter roots and vine length for females. Estimates for total root length (0.76) and root surface area (0.77) were high. The lack of male by female interaction suggests very low dominance genetic variation and contributed to high heritability estimates, which represent predominantly additive gene action. Additive genetic variation allows more-efficient progress by selection, making the potential for root system improvement favorable.

Genetic improvement of early vigour in wheat

1999 ◽  
Vol 50 (3) ◽  
pp. 291 ◽  
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.

Genetic analysis of variation for grain yield and protein concentration in two wheat crosses

1997 ◽  
Vol 48 (5) ◽  
pp. 605 ◽  
Author(s):  
M. A. Fabrizius ◽  
M. Cooper ◽  
K. E. Basford
Keyword(s):  
Genetic Variation ◽  
Grain Yield ◽  
Protein Concentration ◽  
Genetic Correlations ◽  
Wheat Breeding ◽  
High Yield ◽  
Genetic Progress ◽  
Protein Levels ◽  
Independent Segregation ◽  
Analysis Of Variation

Grain yield and protein concentration are two of the more important criteria for wheat breeding in Queensland. Three aspects of the inheritance of both of these traits can have an impact on achieving genetic progress: (i) the magnitude and form of the genetic correlation between the traits, (ii) the magnitude of genetic variation and genotype × environment interactions, and (iii) the importance of epistasis in genetic variation. These 3 factors were examined for 2 crosses in a multi- environment trial conducted in Queensland in 1989. Negative genetic correlations were found between grain yield and protein concentration in both crosses. Genetic variation and genotype × environment interactions were found to be important for both traits. There was little evidence for the existence of significant additive × additive epistasis for either trait and the genotype × environment interactions were predominantly additive × environment in nature. From both crosses, progeny combining the high yield and high protein levels of the parents were identified. This suggests that there was a degree of independent segregation of the genes controlling grain yield and protein concentration in both crosses. Therefore, simultaneous genetic progress for yield and protein concentration is possible in Queensland environments.

scholarly journals Genetic Analysis of Yield and Quality Traits in Switchgrass Based on Population Crosses

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2220
Author(s):  
Serge Edmé ◽  
Rob Mitchell
Keyword(s):  
Genetic Variation ◽  
Combining Ability ◽  
Dry Matter ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Ethanol Yield ◽  
Lignin Content ◽  
Block Design ◽  
Likelihood Method ◽  
Single Pair

Obtaining greater genetic gains, particularly for biomass yield, requires a good understanding of the gene action governing the inheritance of traits with economic importance in switchgrass (Panicum virgatum L.). Individual genotypes from three different accessions were crossed in single-pair matings with reciprocals to assess the relative importance of additive to nonadditive genetic variation and the potential of using inter-ecotypic crosses to improve dry matter yield (DMY), in vitro dry matter digestibility (IVDMD), lignin content (ADL and KL), and ethanol yield (ETOH). Crosses and four reference populations were planted in a randomized complete block design with eight replications of single family-rows plots, with five-plants each and 1 m spacings. A linear mixed model was applied as per the restricted maximum likelihood method, integrated with a pedigree tracing back to the original founders of these parental populations, and augmented with the designation of four genetic groups. Variation due to SCA (specific combining ability) was predominant for all traits, contributing from 20% to 57% of the total phenotypic variation and with Baker’s ratios (GCA/SCA) varying from 0.003 to 0.67. Heritability values calculated at the fullsib-family mean level were moderate to very high. Variation due to GCA (general combining ability) was detected with a lesser significance for DMY and ETOH. A reciprocal GCA effect was present in the form of maternal inheritance for DMY, suggesting the use of the highest biomass-yielding parent as female in inter-ecotypic breeding. Selecting and deploying fullsib families, deploying clonal hybrids, and adopting an introgression breeding approach are all possibilities available to switchgrass breeders to exploit the complementary genes from this germplasm and capitalize on the non-additive genetic variation present in these crosses.

scholarly journals Development of Selection Criteria on Bean Weight Character of Cocoa (Theobroma cacaoL.) through Path Analysis Approach

2013 ◽  
Vol 29 (3) ◽  
Author(s):  
Indah Anita Sari ◽  
Agung Wahyu Susilo
Keyword(s):  
Genetic Variation ◽  
Path Analysis ◽  
Selection Criteria ◽  
Block Design ◽  
Dry Weight ◽  
Variation Coefficient ◽  
Path Coefficient ◽  
Genetic Progress ◽  
Pod Number ◽  
Bean Weight

Path coefficient analysis is frequently used for development of selection criteria on various type of plants. Path analysis on this research was conducted to find the selection criteria of yield component which directly affect bean weight. In addition to the value of path analysis coefficient, genetic variation coefficient, heritability and the value of genetic progress were also studied. The study was conducted at the Indonesian Coffee and Cocoa Research Institute. The research used randomized complete block design consisting of 14 accession numbers and each consisting of three replications. Pod girth, pod length, pod weight, wet beans weight per pod, number of normal beans per pod, number of abnormal beans per pod, dry weight per normal bean, and shell content were observed. The results showed that the pod weight character had an important role in determining the dry weight of normal bean. The character had a positive genotype correlation coefficient values which was high and significantly different (r=0.46) for dry weight per normal bean, considerable direct influence (P=0.479), moderate of the genotype variation coefficient (9.6%), and high genetic progress (95.23). Character of wet bean weight per pod could also be used indirectly for the selection criteria for dry weight per normal bean based on genetic variation coefficient value (11.88%), genetic progress value (82.48), and direct effect on dry weight per normal bean had positive value (P=0.006). Key words: Selection criteria, dry weight per bean, path analysis,Theobroma cacaoL.

scholarly journals EFFECT OF GYPSUM ON EARLY GROWTH AND YIELD OF SWEET POTATO.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1078a-1078
Author(s):  
E. Niyonsaba ◽  
E. G. Rhoden ◽  
P. K. Biswas ◽  
G.W. Carver
Keyword(s):  
Sweet Potato ◽  
Ipomoea Batatas ◽  
Dry Matter ◽  
Block Design ◽  
Early Growth ◽  
Growth And Yield ◽  
Root Weight ◽  
Storage Root ◽  
Root Yield ◽  
And Storage

A study was conducted to assess the effects of gypsum on the early growth and storage root yield of sweet potato (Ipomoea batatas) cvs `Jewel', `Goergia Jet' and `TI-155'. Three rates of gypsum were applied (1.03, 2.06 and 3.09 tons/acre). These represented half, recommended and 1.5 recommended levels. The experiment was a randomized complete block design with a split plot arrangement of treatment. Leaf area, total dry matter, leaf dry matter and stat-age root weight were recorded at 30-day intervals. Plants receiving half the recommended levels of gypsum produced the highest total storage root dry matter (0.306 t/a) and the highest leaf dry matter (0.116 t/a). Although a positive relationship exists between leaf dry matter and storage root yield between 90 and 120 days, there was no such relationship between those parameters either at 30 and 60 days or 60 and 90 days after transplanting.

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