Registration of ‘C‐99R’ Peanut

Maximum (Max) and minimum (Min) peanut (Arachis hypogaea L.) input production tests were conducted for three consecutive years 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,

Section: ------------------------------------% ----------------------mentioning

confidence: 94%

Agronomic Performance and Economic Return among Peanut Genotypes with Maximum and Minimum Production Inputs

Branch¹,

Fletcher²

2010

“…The CBR-resistant cultivar Georgia-02C and the susceptible cultivar C-99R (Gorbet and Shokes, 2002) were used as reference entries to evaluate screening techniques. The reference cultivars were compared to the runner-type peanut genotypes Georgia-01R (Branch, 2002), Georganic , DP-1 (Gorbet, 2003), and the breeding line C34-24-85 in a naturally infested field, in fields following plant inoculations, and in artificially infested soil in the greenhouse.…”

Section: Genotypes Evaluatedmentioning

confidence: 99%

“…Georgia-01R is a recently released cultivar, which has shown some resistance to CBR (Branch, 2002). DP-1 (Gorbet and Shokes, 2002) and Georganic have previously shown multiple resistances to several diseases, such as early leaf spot, late leaf spot, and tomato spotted wilt virus (TSWV) (Cantonwine et al, 2006(Cantonwine et al, , 2008Culbreath et al, 2005). C34-24-85 is a promising breeding line that was the most susceptible to CBR in preliminary tests.…”

Section: Genotypes Evaluatedmentioning

confidence: 99%

Evaluation of Resistance to Cylindrocladium Parasiticum of Runner-Type Peanut in The Greenhouse and Field

Dong¹,

Holbrook²,

Culbreath³

2008

Identification and utilization of peanut cultivars with resistance to Cylindrocladium black rot (CBR) is a desirable approach to manage this disease. The objectives of this study were to improve greenhouse and field screening techniques for resistance to CBR, and to evaluate the reaction of selected runner-type peanut genotypes. Georgia-02C (moderately resistant to CBR) and C-99R (CBR-susceptible) were used in comparing the effectiveness of different inoculation methods in the greenhouse. Disease development was affected by both size and density of microsclerotia in soil. Use of microsclerotia at a size of ≥150 to <250 µm and a density of 1 to 5 microsclerotia/g soil provided the best separation the CBR-resistant cultivar Georgia-02C and the susceptible C-99R based on root rot severity. Genotypes with varying resistance to CBR were evaluated by growth in a naturally infested field, and by inoculating plants in the field and greenhouse. Disease incidence and severity at harvest were the most effective parameters for evaluating CBR resistance in the field and greenhouse, respectively. The cultivars Georgia-02C and Georganic had the lowest disease incidence, whereas C-99R and DP-1 had the highest disease incidence in a naturally infested field in 2005 and 2006. Incidence of CBR was moderate for Georgia-01R in both years, but was inconsistent for C34-24-85. Georgia-02C and Georganic also showed partial resistance to CBR in greenhouse tests. Inoculated plants in the field had similar reaction with Georgia-02C and Georganic showing higher CBR resistance than C-99R and DP-1 in both 2006 and 2007. The root rot severities for genotypes Georgia-02C and Georganic were lower than those for C-99R and DP-1. Incidence of CBR in the naturally infested field was significantly correlated with CBR incidence in the inoculated plants in the field (r = 0.84, P ≤ 0.01), but neither was correlated with disease ratings for greenhouse experiments. Peanut genotypes are most reliably screened by inoculating plants in the field or using uniformly infested fields. Further study is needed to improve greenhouse screening procedures.

“…The entire experimental area was treated with pendimethalin applied preplant plant incorporated at 1.1 kg ai/ha to control annual grasses. 'C99R' (Gorbet and Shokes, 2002) peanut were planted in 2006 and 2007, with 'Georgia Green' (Branch, 1996) planted in 2008. Compared to other cultivars, both of these are considered relatively tolerant of chlorimuron (Wehtje and Grey, 2004).…”

Section: Methodsmentioning

confidence: 99%

Comparing the Risks and Benefits of Early Applications of Chlorimuron for Weed Control in Peanut

Johnson¹,

Prostko²,

Davis³

2010

Chlorimuron is applied from 60 days after peanut (Arachis hypogaea L.) emergence (DAE) until 45 days prior to harvest to control Florida beggarweed [Desmodium tortuosum (Sw.) DC]. Research trials were conducted in Georgia from 2006 to 2008 to determine whether the benefits of controlling smaller weeds earlier in the season compensate for the potential risk of significant peanut injury from chlorimuron. Chlorimuron at 9 g ai/ha was applied at 21, 35, 49, 63, 77, and 91 DAE. Additionally, flumioxazin (105 g ai/ha) preemergence was included as a treated control, along with a nontreated control. Main plots were split into subplots; weed-free and weeds present. Flumioxazin controlled Florida beggarweed 82%. Chlorimuron controlled Florida beggarweed 38 to 67%, with applications 21 and 35 DAE more efficacious than later applications. With weeds present, peanut treated with chlorimuron at any application timing yielded less than peanut treated with flumioxazin. Weed-free peanut treated with chlorimuron at any application timing yielded less than peanut treated with flumioxazin. These data indicate that chlorimuron applied earlier than 60 DAE provided better Florida beggarweed control with greater peanut yield than when applied at the recommended time intervals. However, Florida beggarweed control and peanut yield from any of the chlorimuron treatments were consistently less than flumioxazin.