Transgressive Segregation and Long-Term Consistency for High TSWV Field Resistance in the ‘Georgia-06G’ Peanut Cultivar

2018 ◽  
Vol 19 (3) ◽  
pp. 201-206 ◽  
Author(s):  
W. D. Branch ◽  
A. K. Culbreath

Tomato spotted wilt disease caused by tomato spotted wilt virus (TSWV) is a major peanut (Arachis hypogaea L.) production problem in the United States. TSWV has become endemic since the mid-1980s in the southeastern U.S. peanut production area. ‘Georgia-06G’ is a large-seeded, TSWV-resistant, runner-type peanut cultivar, whereas ‘Georgia Greener’ is a sister line with a smaller seed size than Georgia-06G. Both Georgia-06G and Georgia Greener have greater TSWV general field resistance with higher yields, total sound mature kernels grade, and dollar values than the parents (‘Georgia Green’ and ‘C-99R’), which shows transgressive segregation for these desirable quantitative traits. Therefore, the objective of this 12-year study was to evaluate the higher TSWV host-plant resistance found in the Georgia-06G over time compared with many other runner- and virginia-type peanut cultivars and advanced breeding lines. Despite yearly variability in TSWV and total disease incidence, the data indicate that Georgia-06G exhibited long-term high TSWV and total disease field resistance at midseason and late season, respectively. Georgia-06G was also found to have among the highest pod yield and dollar value every year. The higher general TSWV field resistance of Georgia-06G appears to be consistent across many years and locations, similar to the moderate TSWV resistance in Georgia Green.

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1161-1161 ◽  
Author(s):  
E. Marys ◽  
A. Mejías ◽  
E. Rodríguez-Román ◽  
D. Avilán ◽  
T. Hurtado ◽  
...  

Gerbera (Gerbera jamesonii) and Chrysanthemum (family Asteraceae) are two of the top 10 cut flowers of the world, with great commercial value. Since 1998, Venezuela began a floral industry to produce and export fresh cut gerbera and chrysanthemum, with 40% of nurseries concentrated in Altos Mirandinos (Miranda State, north central region of the country). For the past 2 years, greenhouse-grown gerbera and chrysanthemum have been observed displaying symptoms resembling those associated with tospoviruses. Symptomatic plants showed concentric rings, irregular chlorotic blotches, and deformation on leaves. Disease incidence was estimated at 30%. Mechanical inoculation with extracts of symptomatic leaves reproduced the typical concentric ring symptoms on indicator plants Arachis hypogaea L. cv. San Martín, Capsicum chinense, and G. jamesonii 6 to 15 days after inoculation. In initial tests, leaves from each 30 symptomatic gerbera and chrysanthemum species from several greenhouse facilities in Altos Mirandinos reacted positively when tested by DAS-ELISA with polyclonal antisera (ATCC, Rockville, MD) raised against Tomato spotted wilt virus (TSWV). Total RNA was extracted with the RNeasy Plant Mini kit (QIAGEN, Hilden, Germany) from two gerbera and two chrysanthemum ELISA-positive samples. The TSWV coat protein gene was amplified by conventional reverse transcription (RT)-PCR using primers CP1 TSWV (TTAACTTACAGCTGCTTT) and CP2 TSWV (CAAAGCATATAAGAACTT) (1). A single DNA product of ~823 bp was amplified from all samples. RT-PCR products were directly sequenced in both orientations and sequences were deposited in GenBank (Accession Nos. KF146700 and KF146701 derived from chrysanthemum, KF146702 and KF146703 derived from gerbera). The resulting sequences showed over 99% identity with each other. and were found to be closely related (over 99%) with TSWV isolates deposited in GenBank originating from different hosts from France (FR693058, FR693055), Montenegro (GU339506, GU339508, GU355940), Italy (HQ830187), New Zealand (KC494501), South Korea (KC261967), and the United States (AY744476). To our knowledge, this is the first confirmed report of TSWV infecting gerbera and chrysanthemum in Venezuela. The relatively widespread occurrence of TSWV in Miranda State underscores the need for systematic surveys to assess its incidence and impact on ornamental crops so that appropriate management tactics can be developed. Reference: (1) R. A. Mumford et al. J. Virol. Methods 57:109, 1996.


2005 ◽  
Vol 32 (1) ◽  
pp. 20-24 ◽  
Author(s):  
A. K. Culbreath ◽  
D. W. Gorbet ◽  
N. Martinez-Ochoa ◽  
C. C. Holbrook ◽  
J. W. Todd ◽  
...  

2008 ◽  
Vol 35 (2) ◽  
pp. 92-100 ◽  
Author(s):  
S. D. Riniker ◽  
R. L. Brandenburg ◽  
G. G. Kennedy ◽  
T. G. Isleib ◽  
D. L. Jordan

Abstract Tomato spotted wilt virus (TSWV), a thrips-vectored tospovirus, is an important pathogen of peanut (Arachis hypogaea L.). Development of tolerant cultivars has proven to be one of the most promising methods to manage the disease. Twenty-four genotypes of virginia market-type peanut were monitored in field tests for thrips damage, and TSWV incidence and severity during 2004 and 2005 in North Carolina. The cultivar Gregory had a higher density of adult thrips in foliage than any other genotype, while breeding lines N01057 and N03054E had the lowest density. No significant correlation was detected between thrips density or injury and TSWV incidence. Line N03036EJ had the greatest TSWV incidence, but did not differ from cultivars Gregory or Perry in incidence. Line N00033 had the least TSWV incidence and differed from the cultivars Gregory and Perry. The occurrence of late-season chlorosis or peanut yellowing death (PYD) was highly correlated with TSWV infection (P < 0.0001). Breeding line N02051ol had the greatest incidence of PYD, but did not differ statistically from Gregory or Perry. Lines N03023EF and N01083 had the least PYD incidence. Plants infected with TSWV not expressing foliar symptoms were found in far greater abundance than plants that were infected and symptomatic. Line N03036EJ had the greatest proportion of infected but asymptomatic plants; line N03054E had the least. Susceptible lines are more likely to become infected, rather than just more likely to show spotted wilt symptoms.


2002 ◽  
Vol 29 (2) ◽  
pp. 79-84 ◽  
Author(s):  
J. H. Lyerly ◽  
H. T. Stalker ◽  
J. W. Moyer ◽  
K. Hoffman

Abstract Tomato spotted wilt virus (TSWV) is an important plant pathogen with a wide host range, including the domesticated peanut (Arachis hypogaea L.). After initial outbreaks on peanut during the 1980s, the virus has spread to all peanut-producing states in the U.S. TSWV is transmitted by several species of thrips which are difficult to control with insecticides; therefore, control of TSWV most likely will come from selecting resistant genotypes in breeding programs. Although moderate levels of resistance have been discovered in A. hypogaea, complete virus resistance has not been found. Several Arachis species have desirable genes for plant resistances and tolerate many disease and insect pests better than the cultivated species. The objectives of this study were to (a) evaluate TSWV disease incidence and severity in accessions of Arachis species, and (b) compare levels of TSWV resistance in diploid species to selected A. hypogaea genotypes. In this study, 46 diploid Arachis spp. accessions were evaluated in the greenhouse by artificial inoculation tests for resistance to TSWV. Nine Arachis accessions were observed with no disease symptoms when TSWV isolate 10 was used as opposed to A. hypogaea lines that ranged from moderately to highly susceptible. Additional testing with more virulent isolates identified A. diogoi accession GKP 10602 and A. correntina accession GKP 9530 as highly resistant to the virus. These two accessions are being used as parents in crossing programs to incorporate TSWV resistance genes into A. hypogaea.


Plant Disease ◽  
2005 ◽  
Vol 89 (8) ◽  
pp. 910-910 ◽  
Author(s):  
J. E. Woodward ◽  
T. B. Brenneman ◽  
R. C. Kemerait ◽  
A. K. Culbreath ◽  
J. R. Clark

Because of the importance of spotted wilt caused by Tomato spotted wilt virus (TSWV), most peanut (Arachis hypogaea L.) breeding programs in the southeastern United States are focusing on developing resistance to TSWV. Many of the cultivars with improved resistance to TSWV are late maturing, requiring 150 days to reach optimum maturity. This factor could greatly impact disease problems at harvest. During November of 2004, an unknown disease was observed on peanut cvs. Georgia 02-C and Hull in a commercial field in Appling County. Symptoms included wilting stems with water-soaked lesions and a dense, gray mold growing on infected tissues. Final disease incidence was less than 5%. For isolation, diseased tissue was surface sterilized by soaking in 0.5% sodium hypochlorite for 1 min, air dried, plated on potato dextrose agar (PDA), and incubated at 20°C. Botrytis cinerea Pers.:Fr., causal agent of Botrytis blight, was isolated from the margins of infected tissue. Mycelia were initially white but became gray after 72 h at which time tall, branched, septate conidiophores formed. Mature, unicellular, ellipsoid, hyaline conidia (8.9 × 10.4 μm) formed in botryose heads (1). Hard, black, irregular-shaped sclerotia formed after 2 weeks. Stems of greenhouse-grown peanut plants (cv. Georgia Green) were inoculated with PDA plugs colonized with either B. cinerea or B. allii Munn. Inoculations were made 3 cm below the last fully expanded leaf on wounded and nonwounded tissue. Noncolonized PDA plugs served as controls (n = 9). Plants were arranged in a dew chamber at 20°C in a randomized complete block design. Lesions and spore masses identical to those observed in the field appeared 3 to 5 days after being inoculated with B. cinerea. The B. allii inoculations caused only superficial lesions. After 5 days, mean lesion lengths for B. cinerea were 59 and 37 mm for wounded and nonwounded inoculations, respectively. B. cinerea was recovered from 100% of the symptomatic tissues. Botrytis blight is considered a late-season disease that occurs in cool, wet weather (3). Symptoms similar to those of Botrytis blight were observed on mature and over-mature peanut in Georgia and have been cited as “unpublished observations” (2); however, to our knowledge, this is the first report of the disease in Georgia. Although Botrytis blight is not considered a major peanut disease, it may become more prevalent at harvest as producers utilize late-maturing cultivars to manage spotted wilt. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Guide of Imperfect Fungi. 4th ed. The American Phytopathological Society, St. Paul, MN, 1998. (2) K. H. Garren and C. Wilson. Peanut Diseases. Pages 262–333 in: The Peanut, the Unpredictable Legume. The National Fertilizer Assoc. Washington D.C. 1951. (3) D. M. Porter. Botrytis blight. Pages 10–11 in: Compendium of Peanut Diseases. 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathological Society, St. Paul, MN. 1997.


1961 ◽  
Vol 12 (2) ◽  
pp. 239 ◽  
Author(s):  
K Helms ◽  
NE Grylls ◽  
GS Purss

A disease of peanut (Arachis hypogaea L.) in Queensland, previously referred to as "chlorosis", was identified as being caused by the tomato spotted wilt virus. Symptoms of the disease on peanut are described. Erigeron bonariensis L., Tagetes minuta L., and Trifolium subterraneurn L. are recorded as new hosts. The disease was not seed-transmitted, although seeds developed lesions and were malformed. Infective virus was found in tissues of the integuments of immature seed. The maximum disease incidence recorded in an individual crop was 5.5%. The mean seed yield of diseased plants was 12.7 g per plant, whereas that of healthy plants was 128.2 g.


2012 ◽  
Vol 13 (1) ◽  
pp. 23 ◽  
Author(s):  
A. K. Culbreath ◽  
W. D. Branch ◽  
J. P. Beasley ◽  
R. S. Tubbs ◽  
C. C. Holbrook

Establishing high plant populations helps suppress epidemics of spotted wilt, caused by Tomato spotted wilt virus (TSWV), in peanut (Arachis hypogaea L.). However, seed costs make it desirable to minimize seeding rates used. To determine whether new resistant genotypes can allow use of reduced seeding rates, field experiments were conducted at Tifton, GA, in 2008-2009 in which seven genotypes were combined factorially with two seeding rates, 9.8 and 19.7 seed/m of row. Genotypes included three cultivars (Georgia Green, Georgia-01R, and Georgia-02C) and four advanced breeding lines (GA 052524, GA 052527, GA 052529, and C724-19-25). Across years and genotypes, final incidences of spotted wilt and standardized areas under the spotted wilt disease progress curves were lower, and yields were higher in all other cultivars and breeding lines than in the moderately TSWV-resistant cultivar Georgia Green. Final incidence of spotted wilt was lower in GA 052527 and GA 052529 than in any of the cultivar standards, and yields of all four breeding lines were higher than for any of the three cultivars. Across genotypes, final incidence of spotted wilt and standardized areas under the spotted wilt disease progress curves were lower and yield was higher for the 19.8 seed/m treatment than the 9.8 seed/m. Accepted for publication 30 November 2011. Published 27 February 2012.


2010 ◽  
Vol 37 (1) ◽  
pp. 83-91 ◽  
Author(s):  
W. D. Branch ◽  
S. M. Fletcher

Abstract Maximum (Max) and minimum (Min) peanut (Arachis hypogaea L.) input production tests were conducted for three consecutive years (2004–06) to evaluate agronomic performance and economic return among several runner and virginia genotypes. Mid-April planting dates were used each year. The Max tests included recommended production practices of seeding rate, fertilization, irrigation, and pesticides; whereas, the Min tests excluded irrigation, insecticides, and included only three fungicide sprays. Results showed variation among years, locations, and genotypes for TSWV and total disease incidence, pod yield, gross dollar value, and dollar value return above variable cost. The performance results also show the benefit to growers from agronomic and economic improvement with many of the newly released peanut cultivars in Georgia. Significant differences (P ≤ 0.05) among the peanut genotypes for tomato spotted wilt disease [caused by Tomato spotted wilt virus (TSWV)] where noted. The lowest TSWV incidence was noted for the cultivars Georgia-06G, Georgia Greener, Georgia-07W, Georgia-08V, Georgia-05E, Georgia-03L, Georgia-02C, Georgia-01R, and AP-3. Highest pod yields were found among Georgia-06G, Georgia Greener, Georgia-07W, Georgia-08V, Georgia-05E, and Georgia-01R. In general, the highest average dollar value return above variable cost was found in the Max test as compared to the Min test, and the highest average dollar value return above variable cost including seed cost was found with the runner-type cultivars Georgia-06G and Georgia Greener.


2003 ◽  
Vol 30 (2) ◽  
pp. 108-111 ◽  
Author(s):  
W. D. Branch ◽  
J. A. Baldwin ◽  
A. K. Culbreath

Abstract Tomato spotted wilt virus (TSWV) resistant, runner-type peanut (Arachis hypogaea L.) cultivars are the most important defense to control spotted wilt disease in southeast U.S. peanut production. The objective of this 3-yr (1999–01) study was to evaluate six TSWV-resistant, runner-type cultivars (Southern Runner, Florida MDR 98, C-99R, ViruGard, Georgia Green, and Georgia-OIR) at three different seeding rates (3, 5, and 7 seed/30.5 cm) in single conventional row patterns for possible genotype (GE) × seeding rate (SR) interaction at the Univ. of Georgia, Coastal Plain Experiment Station. The combined split-plot analyses of variance resulted in highly significant (P ≤ 0.01) GE × SR interaction, which indicates that not all six runner-type cultivars performed the same at each of these three seeding rates. A good example was the TSWV-resistant, runner-type peanut cultivar Georgia Green. It performed subpar at the below normal or lowest seeding rate; whereas at the highest seeding rate, Georgia Green and Georgia-OIR produced the highest pod yields and dollar value returns per hectare among all of these runner-type cultivars. TSWV disease incidence was also significantly lower for the TSWV-resistant Georgia Green cultivar at each of the two higher seeding rates compared to the lowest seeding rate.


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