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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF IMPROVED PEANUT GERMPLASM AND RESISTANCE TO DISEASE AND NEMATODE PESTS Title: Evaluation of resistance to Cylindrocladium parasiticum in peanut in the greenhouse and in naturally infested or inoculated fields

Authors
item Dong, W -
item Brenneman, T -
item Holbrook, C
item Culbreath, A -

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 15, 2010
Publication Date: June 20, 2010
Citation: Dong, W.B., Brenneman, T.B., Holbrook Jr, C.C., Culbreath, A.K. 2008. Evaluation of resistance to Cylindrocladium parasiticum in peanut in the greenhouse and in inoculated or naturally infested fields. Peanut Science. 35:139-148.

Interpretive Summary: Cylindrocladium black rot is a serious disease in peanut, and development of resistant cultivars 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 resistance in six runner peanut genotypes. Two peanut cultivars, Georgai-02C (moderate resistance to CBR) and C-99R (CBR-susceptible) were used to compare the effectiveness of different inoculation methods in the greenhouse. Six runner type genotypes with varying resistance to CBR were evaluated in a naturally infested field, inoculated fields, and in greenhouse trials. CBR incidence and severity at harvest were the better variable for evaluating CBR resistance in peanut in naturally infested or inoculated field, and greenhouse experiments, respectively. The genotypes Georgia-02C and Georganic had low incidences, where as C-99R and DP-1 always had high incidences in field and greenhouse trials. CBR incidence in the naturally infested field experiments was significantly correlated with CBR incidence in the inoculated field experiments ( r = 0.84, P < 0.01), but neither was correlated with the disease ratings for greenhouse experiments. Peanut genotypes are most reliably screened in inoculated fields or uniformly infested fields, but greenhouse evaluations may be useful to identify and characterize components of resistance.

Technical Abstract: Screening 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 resistance in six runner peanut genotypes. Two peanut cultivars, Georgai-02C (moderate resistance to CBR) and C-99R (CBR-susceptible) were used to compare the effectiveness of different inoculation methods in the greenhouse. Disease development was affected by both size and density of microsclerotia in the soil, and 150-250 um microsclerotia (ms) at 1-5 ms/g soil could separate the CBR-resistant cultivar Georgia-02C and the susceptible C-99R correctly based on root rot rating. Six runner type genotypes with varying resistance to CBR were evaluated in a naturally infested field, inoculated fields, and in greenhouse trials. CBR incidence and severity at harvest were the better variable for evaluating CBR resistance in peanut in naturally infested or inoculated field, and greenhouse experiments, respectively. The genotypes Georgia-02C and Georganic had low incidences, where as C-99R and DP-1 always had high incidences in a naturally infested field in 2005 and 2006. CBR incidence was moderate in Georgia-01R in both years, but was inconsistent in C34-24-85. Georgia-02C and Georganic also showed partial resistance to CBR in greenhouse tests. In field inoculation experiments, the peanut cultivars Georgia-02C and Georganic showed higher resistance than cultivars C-99R and DP-1 in both 2006 and 2007. The root rot ratings for genotypes Georgia-02C and Georganic were lower than those for C-99R and DP-1. CBR incidence in the naturally infested field experiments was significantly correlated with CBR incidence in the inoculated field experiments ( r = 0.84, P < 0.01), but neither was correlated with the disease ratings for greenhouse experiments. Peanut genotypes are most reliably screened in inoculated fields or uniformly infested fields, but greenhouse evaluations may be useful to identify and characterize components of resistance.

Last Modified: 12/22/2014