Potential for utilization of pepper germplasm with a variable reaction to Sclerotium rolfsii Sacc. to develop southern blight-resistant pepper (Capsicum annuum L.) cultivars

2005 ◽  
Vol 3 (3) ◽  
pp. 326-330 ◽  
Author(s):  
Richard L. Fery ◽  
Philip D. Dukes
Keyword(s):  
Sclerotium Rolfsii ◽  
Recessive Gene ◽  
Field Trials ◽  
Resistant Parent ◽  
Frequency Distributions ◽  
Southern Blight ◽  
Backcross Populations ◽  
Breeding Programmes ◽  
High Level ◽  
Effective Use

The bell-type pepper cultivar Golden California Wonder, a source of resistance to southern blight, was crossed with the susceptible cultivar Sweet Banana. The F1, F2 and backcross progenies of this cross and the parental lines were evaluated in an inoculated field study for their reactions to Sclerotium rolfsii Sacc. A categorical rating system was used to rate plants for severity of wilting and severity of stem-lesion development. The plants within all three non-segregating populations (the resistant parent, the susceptible parent and the F1) displayed a range of reactions to S. rolfsii. Variable reactions to S. rolfsii among homogeneous pepper populations were expected because this phenomenon is well documented in the literature and we had observed similar responses in field trials conducted over multiple years. The high level of variation for reactions to S. rolfsii exhibited by the parental and F1 hybrid populations and the categorical system of rating individual plants placed severe limitations on the effective use of any quantitative type of analysis. Accordingly, a weighting procedure was used to correct the F2 and backcross populations based on frequencies of apparent mis-classifications in the parental and F1 populations. Examination of the comparative frequency distributions of the parental and progeny populations and examination of the weighted segregation data suggest that the southern blight resistance in ‘Golden California Wonder’ is conditioned by a single recessive gene. The level of resistance conditioned by this reputed recessive gene appears high enough to recommend it for use in pepper breeding programmes.

scholarly journals Performance of nematode-resistant white clover in field trials

2005 ◽  
pp. 29-34
Author(s):  
C.F. Mercer ◽  
R.N. Watson ◽  
D.R. Woodfield
Keyword(s):  
White Clover ◽  
Field Trials ◽  
Cyst Nematode ◽  
Root Knot Nematode ◽  
Plant Vigour ◽  
Resistant Lines ◽  
Breeding Programmes ◽  
Clover Root ◽  
High Level ◽  
Better Than

Breeding for improved resistance and tolerance to the clover root-knot nematode, Meloidogyne trifoliophila, and the clover cyst nematode, Heterodera trifolii , has been successful in white c lover, Trifolium repens. White clover lines developed from three independent breeding programmes were established in field trials at Lincoln, Palmerston North, Cambridge and Kerikeri. Plants were established in areas either untreated or treated with nematicide, so as to have contrasting pest loads on the plant material and evaluated for up to 4 years. Plant vigour was scored before each grazing at each site. Clover cyst nematode cysts were counted twice in Palmerston North and all nematodes were counted in stained roots on four occasions in Cambridge. Resistant lines from the clover cyst nematode programme performed better than susceptible lines and as well as most cultivars reflecting the high level of resistance developed in this glasshouse-based programme. This resistance was also reflected in the generally lower number of cysts counted under resistant lines from Palmerston North. The root-knot nematode resistant material performed better than the susceptible and as well as most cultivars. The tolerance selections, developed under field conditions, performed as well as, or better than the cultivars. The selections from the breeding programmes have exhibited strong agronomic potential across locations and years and the best material has been crossed, with progeny being assessed in current field trials. Keywords: Heterodera trifolii, Meloidogyne trifoliophila, nematode, pasture, resistance, tolerance, white clover

scholarly journals GENETIC AND PHYSIOLOGICAL ANALYSIS OF SUCROSE ACCUMULATION IN TOMATO FRUIT

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 584b-584
Author(s):  
John R. Stommnel
Keyword(s):  
Tomato Fruit ◽  
Sugar Content ◽  
Recessive Gene ◽  
Sucrose Phosphate Synthase ◽  
Soluble Solids ◽  
Sucrose Accumulation ◽  
Backcross Populations ◽  
Physiological Analysis ◽  
High Concentrations ◽  
High Level

Fruit of the cultivated tomato, Lycopersicon esculentum, accumulate the reducing sugars glucose and fructose as the primary storage carbohydrates. In contrast, fruit of several wild green-fruited species store high concentrations of sucrose. Analysis of invertase, sucrose synthase (SS) and sucrose phosphate synthase (SPS) enzyme activity throughout fruit development in the sucrose accumulating species L. peruvianum, indicated low levels of invertase and SS during the period of significant sucrose accumulation. Increased SPS activity was noted during the sucrose accumulation phase but was not coincident with maximum rates of sucrose accumulation. The percent soluble solids in ripe L. peruvianum fruit was more than twice that present in L. esculentum and attributed primarily to the high level of sucrose accumulated in L. peruvianum. Analysis of fruit sugar content in F1, F2 and backcross populations derived from an initial cross between plants of sucrose and hexose accumulators suggests that recessive gene(s) are responsible for sucrose accumulation.

scholarly journals Southern Blight (Sclerotium rolfsiiSacc.) of Cowpea: Genetic Characterization of Two Sources of Resistance

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Richard L. Fery ◽  
Philip D. Dukes
Keyword(s):  
Resistance Genes ◽  
Sclerotium Rolfsii ◽  
Field Studies ◽  
Sources Of Resistance ◽  
Frequency Distributions ◽  
Southern Blight ◽  
Segregation Data ◽  
Cowpea Cultivars ◽  
Dominant Genes

Field studies were conducted to characterize the genetic nature of resistance to southern blight (caused bySclerotium rolfsiiSacc.) exhibited by the cowpea [Vigna unguiculata(L.) Walp.] cultivars Carolina Cream and Brown Crowder and to determine if a genetic relationship exists for this resistance between the two cultivars. Examination of the comparative frequency distributions of the parental and progeny populations of the “Carolina Cream” x “Magnolia Blackeye” and “Brown Crowder” x “Magnolia Blackeye” crosses and the corresponding segregation data indicates that the southern blight resistances exhibited by “Carolina Cream” and “Brown Crowder” are conditioned by single dominant genes. Examination of the segregation data from the parental and progeny populations of the “Carolina Cream” x “Brown Crowder” cross suggests that the two resistance genes are not allelic. The availability of each of the resistance genes in cultivar-type genetic backgrounds should allow for rapid incorporation of southern blight resistance genes into other cowpea cultivars by the application of conventional plant breeding methodologies.

scholarly journals Genetic Resistance in Melon PI 313970 to Cucurbit yellow stunting disorder virus

HortScience ◽  
2011 ◽  
Vol 46 (12) ◽  
pp. 1582-1587 ◽  
Author(s):  
James D. McCreight ◽  
William M. Wintermantel
Keyword(s):  
United Arab Emirates ◽  
Genetic Resistance ◽  
Recessive Gene ◽  
Field Tests ◽  
Imperial Valley ◽  
Frequency Distributions ◽  
Western Mexico ◽  
High Level ◽  
Whitefly Vector ◽  
Level Resistance

Melon (Cucumis melo L.) is a fresh vegetable and dessert fruit that may also be cooked or dried, processed for juice and flavoring, and the seeds of which are a source of high-quality cooking oil and high protein seed meal. Melon production throughout many parts of the world is now threatened by the crinivirus Cucurbit yellow stunting disorder virus (CYSDV) in tropical and subtropical areas favorable to its whitefly vector. CYSDV is transmitted by the sweetpotato whitefly, Bemisia tabaci Gennadius, biotypes A, B, and Q. CYSDV first appeared on melon in the 1980s in the United Arab Emirates and emerged on melon in the Yuma, AZ, and Imperial Valley, CA, regions and western Mexico during the Fall season of 2006 followed by Florida in 2007. PI 313970, C. melo var. acidulus Naudin, a salad-type melon from India, expressed high-level resistance to CYSDV in Yuma and Imperial Valley in Fall 2006, but it was not immune; the virus was detected in asymptomatic plants. Inheritance of resistance to CYSDV in PI 313970 was studied in three naturally infected, replicated field tests in Imperial Valley during the Fall seasons of 2007 and 2008 and the Spring season of 2009. Resistance in PI 313970 was recessive: all F1 PI 313970 (PI) × susceptible ‘Top Mark’ (TM) and BCTM individuals were susceptible, and the F2 and BCPI segregated 3:1 and 1:1 susceptible to resistance, respectively. Frequency distributions of CYSDV symptom severity ratings suggested a single recessive gene in PI 313970 for resistance to CYSDV. PI 313970 was, however, observed to be variable for resistance; a few plants in each test expressed distinct symptoms of CYSDV infection and its frequency distributions overlapped those of ‘Top Mark’. This variation may represent genetic variation selectable for uniform reaction to infection by CYSDV or phenotypic variation in the resistant reaction. The genetic relationship between the genes for resistance to CYSDV in PI 313970 (recessive) and TGR-1551 (dominant) is not known.

scholarly journals Inheritance of Resistance to Zucchini Yellow Fleck Virus in Cucumis sativus L.

HortScience ◽  
1995 ◽  
Vol 30 (2) ◽  
pp. 336-337 ◽  
Author(s):  
F. Gilbert-Albertini ◽  
M. Pitrat ◽  
H. Lecoq
Keyword(s):  
Recessive Gene ◽  
Single Recessive Gene ◽  
Single Plant ◽  
Plant Selection ◽  
Cucumis Sativus L ◽  
Mediterranean Countries ◽  
Backcross Populations ◽  
Single Plant Selection ◽  
High Level ◽  
Selection Of

Zucchini yellow fleck virus (ZYFV) is a potyvirus that occurs in cucurbits grown in some Mediterranean countries. `Marketer' cucumber responded to ZYFV infection with a severe mosaic, stunting, and leaf and fruit deformation. A high level of resistance to this virus was found in a single plant selection of `Taichung Mou Gua' (TMG) cucumber from Taiwan. In F2 and backcross populations involving TMG × `Marketer', the resistance to ZYFV was determined to be conferred by a single recessive gene, to which the symbol zyf is assigned.

scholarly journals Inheritance of Resistance to a Strain of Passionfruit Woodiness Virus in Pea (Pisum sativum L.)

HortScience ◽  
1994 ◽  
Vol 29 (8) ◽  
pp. 901-902 ◽  
Author(s):  
R. Provvidenti ◽  
C.L. Niblett
Keyword(s):  
Genetic Factors ◽  
Recessive Gene ◽  
Yellow Mosaic Virus ◽  
Susceptible Cultivar ◽  
Single Recessive Gene ◽  
Plant Introductions ◽  
Pisum Sativum L ◽  
Backcross Populations ◽  
Pea Resistance ◽  
High Level

An Australian strain of passionfruit woodiness potyvirus (PWV-K) infected peas and caused a light to moderate mosaic consisting of chlorotic spots, veinal chlorosis, and some plant stunting. Resistance to PWV-K was found in pea cultivars and plant introductions (PI) known to be resistant to bean yellow mosaic virus (BYMV). In cross and backcross populations involving the resistant cultivar Bonneville (United States) and PI 140295 (Iran) with the susceptible cultivar Ranger, a single recessive gene was responsible for the high level of resistance to PWV-K. From crosses involving PI 391630 (China), which is resistant to BYMV but susceptible to PWV-K, and the cultivar Bonneville (resistant to both viruses), it was evident that different genetic factors conferred resistance to these two potyviruses. The symbol pwv is tentatively assigned to this newly recognized pea resistance gene. Three other Australian strains of PWV did not infect peas.

scholarly journals Inheritance of Resistance to the Florida Strain of Zucchini Yellow Mosaic Virus in Watermelon

HortScience ◽  
1991 ◽  
Vol 26 (4) ◽  
pp. 407-408 ◽  
Author(s):  
R. Provvidenti
Keyword(s):  
Mosaic Virus ◽  
Citrullus Lanatus ◽  
Zucchini Yellow Mosaic Virus ◽  
Recessive Gene ◽  
The United States ◽  
Yellow Mosaic Virus ◽  
Plant Selection ◽  
Backcross Populations ◽  
Single Plant Selection ◽  
High Level

A high level of resistance to zucchini yellow mosaic virus (ZYMV) was found in four landraces of Citrullus lanatus (Thunb.) MatSum. & Nakai (PI 482322, PI 482299, PI 482261, and PI 482308) originally collected in Zimbabwe. This resistance is specific to the Florida strain of the virus (ZYMV-FL), which prevails in the United States. Inheritance studies were conducted by using a single-plant selection (PP261-I) of PI 48226I and the ZYMV-susceptible watermelon cultivar New Hampshire Midget. In F1, F2, and reciprocal backcross populations, resistance was conferred by a single recessive gene to which the symbol zym is assigned. There was no linkage between zym and one of the three homodimer bands of the isozyme phosphoglucoisomerase (Pgi-2b), which was found in PP261-1, and in other ZYMV-FL resistant plants.

scholarly journals Use of non-chemical methods for the management of southern blight disease of carrot incited by Sclerotium rolfsii

2020 ◽  
Vol 1 (2) ◽  
pp. 74-85
Author(s):  
M. Tanbir Rubayet ◽  
Farhana Prodhan ◽  
M. Shamim Hossain ◽  
Minhaz Ahmed ◽  
M. Abdullah Al Mamun ◽  
...  
Keyword(s):  
Radial Growth ◽  
Sclerotium Rolfsii ◽  
Field Trials ◽  
Soil Solarization ◽  
Leaf Extracts ◽  
Southern Blight ◽  
Blight Disease ◽  
Th 1

This experiment was conducted to assess the effect of Trichoderma harzianum, soil solarization, and biofumigant on southern blight dis-ease of carrot incited by Sclerotium rolfsii isolate CS 5. A series of in-vitro and in-vivo trials laid out to select a virulent isolate of S. rolfsii against the carrot variety New Kuroda and evaluated the mustard, cabbage, cauliflower, and broccoli leaf extracts for choosing an effec-tive biofumigant against test pathogen. Mustard was the most effec-tive in inhibiting the radial growth, and sclerotia formation (80.37 and 83.37%) of S. rolfsii (isolate CS 5) at 40% level of concentration followed by cabbage leaf extract (62.22 and 68.69%). On the contrary, a total of 10 isolates of T. harzianum were screened against the test pathogen on Potato Dextrose Agar (PDA) medium for choosing a dominant isolate of T. harzianum. The isolate Th-6 was found as the most active in inhibiting the radial growth (84.44%) of S. rolfsii fol-lowed by Th-1 (75.56%). In the application of T. harzianum, biofumi-gation, and soil solarization, the treatment appeared to be the most superior in reducing pre- and post-emergence mortality of carrot during secondary field trials. The lowest southern blight disease inci-dence (10.77%), and disease severity (12.78%) were found at the same treatment. Subsequently, the yield of carrot was increased 155.18% which might be due to the reduction of carrot disease as well as the addition of organic materials in the soil.

scholarly journals Grafting Tomato with Interspecific Rootstock to Manage Diseases Caused by Sclerotium rolfsii and Southern Root-Knot Nematode

Plant Disease ◽  
2010 ◽  
Vol 94 (8) ◽  
pp. 1015-1021 ◽  
Author(s):  
C. L. Rivard ◽  
S. O'Connell ◽  
M. M. Peet ◽  
F. J. Louws
Keyword(s):  
Sclerotium Rolfsii ◽  
Crop Productivity ◽  
Field Trials ◽  
Root Knot Nematode ◽  
Fresh Market ◽  
Root Knot Nematodes ◽  
Tomato Production ◽  
Southern Blight ◽  
Growing Seasons ◽  
Progress Curve

Southern blight (Sclerotium rolfsii) and root-knot nematodes (Meloidogyne spp.) cause severe damage to fresh-market tomato (Solanum lycopersicum) throughout the southeastern United States. Grafting is an emerging technology in U.S. tomato production, and growers require information regarding the resistance characteristics conferred by rootstocks. In this study, southern blight (SB) and root-knot nematodes (RKN) were effectively managed using interspecific hybrid rootstocks. During 2007 and 2008, field trials were carried out at two locations that had soils naturally infested with S. rolfsii. At the end of the growing seasons, the mean SB incidence of nongrafted plants was 27 and 79% at the two sites. SB incidence among plants grafted onto rootstock cultivars Big Power (one location only), Beaufort, and Maxifort ranged from 0 to 5%, and area under the disease progress curve (AUDPC) values were lower than for nongrafted and self-grafted controls (P < 0.01). At one location, soils were naturally infested with RKN, and all three rootstocks reduced RKN AUDPC and RKN soil populations at first harvest (P < 0.01). Big Power was particularly effective at reducing RKN galling and RKN soil populations at final fruit harvest (P < 0.01). Fruit yield was higher when resistant rootstocks were utilized (P < 0.05), and in our study grafting was effective at maintaining crop productivity in soils infested with S. rolfsii and M. incognita.

Heritability of the Effect of Corticosteroids on Intraocular Pressure

1970 ◽  
Vol 19 (1-2) ◽  
pp. 264-267 ◽  
Author(s):  
F.H. Reuling ◽  
J.T. Schwartz
Keyword(s):  
Intraocular Pressure ◽  
Clinical Signs ◽  
Topical Steroids ◽  
Frequency Distributions ◽  
Steroid Response ◽  
Large Numbers ◽  
Wide Range ◽  
Allele Pair ◽  
High Level ◽  
Genetically Determined

In the late 1950's and early 1960's, it became evident that some glaucoma patients developed elevations of intraocular pressure, which were difficult to control, following prolonged use of systemic or ocular medications containing corticosteroids (Chandler, 1955, Alfano, 1963; Armaly, 1963). In addition, some patients without glaucoma, when treated with steroids for long periods of time, developed clinical signs of chronic simple glaucoma (McLean, 1950; François, 1954; Covell, 1958; Linner, 1959; Goldman, 1962). Fortunately, the elevation of intraocular pressure was reversible if the drug was discontinued.Over the past decade, extensive investigation of the “steroid response” has been undertaken. For this presentation, the steroid response may be considered as a gradual elevation of intraocular pressure, occurring over several weeks, in an eye being medicated with corticosteroid drops several times a day. The elevation in pressure is usually accompanied by a reduction in the facility of aqueous outflow. When relatively large numbers of subjects were tested with topical steroids, so that a wide range of responsiveness could be observed, a variation in individual sensitivity was demonstrated. Frequency distributions of intraocular pressure or change in pressure following steroids showed a skew toward the high side. On the basis of trimodal characteristics which they observed in such frequency distributions, Becker and Hahn (1964), Becker (1965) and Armaly (1965, 1966) considered the possible existence of several genetically determined subpopulations. These investigators distinguished three subpopulations on the basis of low, intermediate, and high levels of pressure response. It was hypothesized that these levels of response characterized three phenotypes, corresponding to the three possible genotypes of an allele pair, wherein one member of the pair determined a low level of response, and the other member determined a high level of response (Armaly, 1967).

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