Trait Heritability Estimates of an Open-pollinated Onion Population

Heritability estimates of bolting percentage (BP), pink root (PR) and Fusarium basal rot (FBR) incidences, and percentage of single centered (PSC) bulbs were calculated for an intermediate-day, open-pollinated onion population using selection response and half-sib (HS) family analyses. BP was determined by counting the number of seedstalks per plot when the population was seeded at an earlier planting date to induce bolting. PR and FBR incidences were determined by rating 30 bulbs/plot for the severity of PR and FBR, and calculated an incidence rate from the number of infected bulbs out of 30 rated. The PSC bulbs was determined by cutting transversely 30 bulbs at the vertical center of the bulb and looking for the presence of a single growing point or multiple growing points within 1.3 cm from the center of the bulb. Families were also evaluated for bulb quality that consisted of shape, size, maturity, firmness, number of scale layers, and dry outer scale thickness, adherence, retention, and color. Families were selected based upon an index that equally weighted BP, PR and FBR incidences, PSC bulbs, and bulb quality. No progress was made for BP even though the narrow sense heritability (h2) estimate was 0.51. PR and FBR incidence was reduced by 18% and 12%, respectively, and realized heritability (RH) estimates of 0.65 and 0.60, respectively, were calculated. h2 estimates calculated through HS family analysis was 0.46 and 0.37, respectively, for these two traits. Very little progress was made for the PSC bulbs and this was reflected in a RH estimate of 0.17. However, the h2 estimate was 0.71, suggesting that progress should be possible.

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Onion Trait Heritability and Response from Selection

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.131.5.646 ◽

2006 ◽

Vol 131 (5) ◽

pp. 646-650 ◽

Cited By ~ 5

Author(s):

Christopher S. Cramer

Keyword(s):

Recurrent Selection ◽

Disease Incidence ◽

Heritability Estimate ◽

Selection Response ◽

Response Analysis ◽

Realized Heritability ◽

Basal Rot ◽

Fusarium Basal Rot ◽

Sib Families ◽

Heritability Estimates

Realized heritability estimates of bolting percentage, pink root and fusarium basal rot severities and incidences, and percentage of single-centered bulbs were estimated for half-sib families of an intermediate-day, open-pollinated onion (Allium cepa L.) population using selection response analysis. Half-sib families were selected based upon an index that equally weighted bolting percentage, pink root and fusarium basal rot severities and incidences, percentage of single-centered bulbs, and bulb quality. Families were subjected to one cycle of half-sib family recurrent selection. Pink root and fusarium basal rot severity was reduced by 17% and 7%, respectively, with realized heritability estimates of 1.28 and 0.65, respectively. More progress for pink root severity was made than was selected. Disease incidence was reduced by 18% and 12%, respectively, with heritability estimates of 0.65 and 0.60, respectively. Very little progress was made for the percentage of single-centered bulbs and this was reflected in a heritability estimate of 0.17. Selection based upon multiple characters at the same time may reduce the effectiveness of making improvements in a single trait. However even with low to moderate heritability, improvements were made, and suggest that further improvements can be made through selection.

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Heritability Estimates of the Pungency and Single-center Traits in Onion

HortScience ◽

10.21273/hortsci.30.4.822e ◽

1995 ◽

Vol 30 (4) ◽

pp. 822E-822

Author(s):

Marisa M. Wall ◽

Ayaz Mohammad ◽

Joe N. Corgan

Keyword(s):

Pyruvic Acid ◽

Selection Response ◽

Realized Heritability ◽

Single Center ◽

Fresh Weight ◽

Breeding Lines ◽

Progeny Analysis ◽

Heritability Estimates ◽

Estimated Heritability

Heritabilities of the pungency and single-center traits were estimated in onion breeding lines using selection response and half-sib family analyses. Pungency was determined by measuring enzymatically produced pyruvic acid in individual bulbs. After one generation of selection, pungency was lowered by 0.37 and 0.42 μmol pyruvic acid/gram fresh weight in the breeding lines 90-61-1 and 89-69-8, respectively, and realized heritabilities of 0.21 and 0.51 were estimated. Heritability estimates calculated through half-sib progeny analysis were 0.53, 0.48, and 0.25 for pungency in the breeding lines 90-61-1, 90-62, and 89-69-8, respectively. The number of single-centered onions was increased by 19% and 22% in the lines 90-62 and 89-69-8, respectively, after one generation of selection, and the realized heritability estimates were 0.37 and 0.34, respectively.

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Fusarium basal rot: profile of an increasingly important disease in Allium spp.

Tropical Plant Pathology ◽

10.1007/s40858-021-00421-9 ◽

2021 ◽

Author(s):

Dung Le ◽

Kris Audenaert ◽

Geert Haesaert

Keyword(s):

Disease Management ◽

Cultural Practices ◽

Current Knowledge ◽

Management Strategies ◽

Future Directions ◽

Basal Rot ◽

Major Constraint ◽

Fusarium Basal Rot ◽

Chemical Pesticides ◽

Important Disease

AbstractFusarium basal rot (FBR) is a soil-borne disease that affects Allium species worldwide. Although FBR has long been recognized as a major constraint to the production of economically important Allium species, information that could support disease management remains scattered. In this review, the current knowledge on the causal agents, symptomology and epidemiology, impact, and management strategies of FBR is synthesized. We highlight that FPR is associated with different complexes of several Fusarium species, of which Fusarium oxysporum and F. proliferatum are the most prevalent. These pathogenic complexes vary in composition and virulence, depending on sites and hosts, which can be challenging for disease management. Research to improve disease management using chemical pesticides, resistance cultivars, biocontrol agents, and cultural practices has achieved both promising results and limitations. Finally, research needs and future directions are proposed for the development of effective FBR management strategies.

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EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON SHORT-TERM RESPONSE TO SELECTION FOR POSTWEANING GAIN IN MICE

Genetics ◽

10.1093/genetics/73.3.513 ◽

1973 ◽

Vol 73 (3) ◽

pp. 513-530

Author(s):

J P Hanrahan ◽

E J Eisen ◽

J E Legates

Keyword(s):

Population Size ◽

Selection Response ◽

Selection Intensity ◽

Realized Heritability ◽

Family Selection ◽

Effective Population ◽

Population Sizes ◽

Selection For ◽

Selection Intensities ◽

Term Response

ABSTRACT The effects of population size and selection intensity on the mean response was examined after 14 generations of within full-sib family selection for postweaning gain in mice. Population sizes of 1, 2, 4, 8 and 16 pair matings were each evaluated at selection intensities of 100% (control), 50% and 25% in a replicated experiment. Selection response per generation increased as selection intensity increased. Selection response and realized heritability tended to increase with increasing population size. Replicate variability in realized heritability was large at population sizes of 1, 2 and 4 pairs. Genetic drift was implicated as the primary factor causing the reduced response and lowered repeatability at the smaller population sizes. Lines with intended effective population sizes of 62 yielded larger selection responses per unit selection differential than lines with effective population sizes of 30 or less.

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Evaluation of Green Manure Amendments for the Management of Fusarium Basal Rot (Fusarium oxysporumf.sp.cepae) on Shallot

International Journal of Agronomy ◽

10.1155/2014/150235 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Assefa Sintayehu ◽

Seid Ahmed ◽

Chemeda Fininsa ◽

P. K. Sakhuja

Keyword(s):

Green Manure ◽

Agricultural Research ◽

Disease Incidence ◽

Limiting Factors ◽

Lepidium Sativum ◽

Ethiopian Mustard ◽

Basal Rot ◽

Fusarium Basal Rot ◽

Manure Amendments

Shallot (Allium cepaL. var.ascalonicum) is the most traditional vegetable crop in Ethiopia. Shallot is susceptible to a number of diseases that reduce yield and quality, among which fusarium basal rot (FBR) caused byFusarium oxysporumf.sp.cepae (Foc)is one of the most important yield limiting factors in Ethiopia. The present study was designed to evaluate the effectiveness ofBrassicacrops for the management of shallot FBR on shallot. The experiments were carried out at Debre Zeit Agricultural Research Center using cabbage (Brassica oleracea), garden cress (Lepidium sativum), Ethiopia mustard (B. carinata), and rapeseed (B. napus). The evaluations were done underin vitroand greenhouse conditions. Underin vitrotest condition it was confirmed that extracts of Ethiopian mustard and rapeseed showed higher inhibition on the growth ofFocpathogen compared to control. Data on seedling emergence, plant height, plant stand, disease incidence, severity, cull bulbs, and bulb weight were collected in greenhouse experiment. The green manure amendments of rapeseed and Ethiopian mustard significantly reduced disease incidence by 21% and 30% and disease severity by 23% and 29%, respectively. However the plant emergency was not significantly different among treatments in greenhouse test. These results indicated that Ethiopian mustard and rapeseed crops have potential as green manure for the management of FBR disease of shallot crop.

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Comparing Efficiencies of Two Selection Approaches for Improving Fusarium Basal Rot Resistance in Short-Day Onion after a Single Cycle of Selection

Horticulturae ◽

10.3390/horticulturae6020026 ◽

2020 ◽

Vol 6 (2) ◽

pp. 26

Author(s):

Subhankar Mandal ◽

Ashish Saxena ◽

Christopher S. Cramer ◽

Robert L. Steiner

Keyword(s):

Environmental Factors ◽

Random Distribution ◽

Single Cycle ◽

Field Screening ◽

Selection Cycle ◽

Short Day ◽

Basal Rot ◽

Fusarium Basal Rot ◽

Consistent Method ◽

Screening Approaches

The development of Fusarium Basal Rot (FBR)-resistant onion cultivars through field and seedling screening approaches faces tremendous challenges due to non-uniform distribution of the disease pathogen and possible multiple mechanisms of host–plant resistance. This study compared the efficiencies of these two methods for increasing FBR resistance of short-day onion after a single selection cycle. Asymptomatic plants or bulbs of seven onion cultivars were selected using a seedling screen performed in a growth chamber or a field screening of mature bulbs. Original and selected populations were evaluated for their responses to FBR stress thereafter employing the same two methods used for screening. The field screening of mature bulbs was found unreliable in both selection and evaluation, likely due to a non-random distribution of the FBR pathogen and variable environmental factors present in the field. The seedling screening successfully increased FBR resistance in the selected cultivar populations revealed by a seedling evaluation. From the results, it is recommended to use a consistent method for both screening and evaluation to make the most selection progress.

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Heritability of Metribuzin Tolerance in Sweet Potatoes (Ipomoea batatas)

Weed Science ◽

10.1017/s0043174500060860 ◽

1987 ◽

Vol 35 (5) ◽

pp. 715-719 ◽

Cited By ~ 6

Author(s):

Howard F. Harrison ◽

Alfred Jones ◽

Philip D. Dukes

Keyword(s):

Ipomoea Batatas ◽

Selection Process ◽

Mass Selection ◽

Fresh Weight ◽

Sweet Potatoes ◽

Narrow Sense Heritability ◽

Shoot Fresh Weight ◽

Potting Medium ◽

Wide Range ◽

Heritability Estimates

Twenty-two sweet potato [Ipomoea batatas(L.) Lam.] clones with a wide range in metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] tolerance were used to establish narrow sense heritability estimates (h2) using a greenhouse procedure. The heritability estimates were obtained from simple linear regressions (h2= 2b) of injury rating, shoot fresh weight, and change in shoot fresh weight of offspring against the same responses of parents at metribuzin concentrations of 0, 0.3, and 0.6 ppm in the potting medium and averaged data for the two concentrations. These values ranged from 0.85 to 1.0, indicating that a recurrent mass selection process should be an appropriate approach to developing metribuzin-tolerant cultivars. Several highly tolerant clones were identified.

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Selection for the length of the spermatozoan midpiece in the mouse

Genetics Research ◽

10.1017/s0016672300002524 ◽

1970 ◽

Vol 16 (3) ◽

pp. 261-275 ◽

Cited By ~ 20

Author(s):

D. M. Woolley

Keyword(s):

Electron Microscope Study ◽

Selection Response ◽

Sperm Cells ◽

Realized Heritability ◽

Family Selection ◽

Selected Lines ◽

Selection Programme ◽

Proportionate Change ◽

The Subject ◽

Selection For

SUMMARYA subcellular dimension, the length of the spermatozoan midpiece, has been the subject of a two-way selection programme in mice. After thirteen generations of within-family selection the divergence between the selected lines amounted to 5·4 phenotypic standard deviations. The realized heritability was found to be 0·76 ± 0·02, dominance and commonenvironmental effects being apparently very small. The reality of the selection response was verified in measurements on live spermatozoa. Other measurements have shown that the change in the length of the midpiece has been independent of its width, and has occurred without a proportionate change in the length of the main-piece of the flagellum. An electron microscope study has shown that the selection has, in fact, brought about changes in the quantity of mitochondrial material in the sperm cells.

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