Reaction of the Core Collection of Peanut Germplasm to Sclerotinia Blight and Pepper Spot1

Abstract

In 2001, entries from the peanut core collection, a subset of the USDA peanut germplasm collection, were planted in non-replicated plots in a field with a history of Sclerotinia blight caused by Sclerotinia minor. Variability existed among entries for reaction to Sclerotinia blight. Of the 744 entries evaluated, 11% had no disease, nearly 30% had ,10% disease incidence, and only 21% had 50% disease incidence or more. Most of the resistant entries had an upright growth habit and were in early and mid-maturity groups. Many of the early maturing entries were susceptible to the foliar disease pepper spot which occurred throughout the study. Entries were selected for further evaluation in replicated plots based on a nil to low (,10% 208, 128, 804, 582, and 273 combined resistance to Sclerotinia blight, pepper spot, and web blotch with less than erect growth habits. Entry 103 had good Sclerotinia blight resistance and yield, but an upright growth habit. Entry 92 had an upright growth habit and low yield, but good Sclerotinia blight resistance. Entries 92 and 103 had upright growth habits but were among the best entries for resistant to pepper spot and web blotch. Entries 426, 184, and 562 were upright and susceptible to pepper spot, but had resistance to web blotch and the best resistance to Sclerotinia blight. These entries appear to be useful sources of resistance to Sclerotinia blight for breeding programs and for increasing the probability of finding additional sources of resistance in clusters of germplasm identified within the entire USDA collection.

Growth Chamber Assay for Evaluating Resistance to Athelia rolfsii

“…resistance because other characteristics such as open canopy structure can create microclimates unfavorable for disease (Blad et al, 1978;Dow et al, 1988;Bailey and Brune, 1997). For example, the cultivar Southwest Runner (Damicone et al, 2010) and several mini-core accessions including CC038, CC068, and CC787 (Bennett et al, 2018) exhibit resistance to Sclerotinia minor in the field but are susceptible when inoculated in the laboratory. While severe outbreaks of A. rolfsii are rare in current peanut production areas of Oklahoma, an inoculated field study of the U.S. mini-core that included three cultivars used here indicated that the A. rolfsii assays may correlate with field results.…”

Screening of the Argentinean INTA peanut core collection with a molecular marker associated with resistance to Sclerotinia minor Jaggar

“…Previously, the marker used in this study was shown to be significantly associated with resistance to Sclerotinia blight in peanut cultivars and PIs that had been thoroughly evaluated in field trials (Chenault et al, 2009). The marker has been used previously to screen numerous germplasm collections Chamberlin, 2014;Chamberlin and Puppala, 2018) and the results obtained have been shown to closely agree with phenotypic reaction to S. minor in field trials (Chenault et al, 2009;Chamberlin et al, 2010;Damicone et al, 2010;Bennett et al, 2018). The results of the current study are similar to those reported when the marker was used to screen other collections, with the marker for resistance being prominent in the fastigiata, vulgaris, and hirsuta botanical types.…”

Registration of ‘Lariat’ Peanut

“…Lariat is the result of a cross between the cultivar Red River Runner and US germplasm collection PI 274193, an accession identified by Damicone et al (2010) as having a prostrate growth habit and excellent resistance to Sclerotinia blight, web blotch (caused by Phoma arachidicola Marasas et al), and pepper spot [caused by Leptosphaerulina crassiasca (Sechet) C.R. Jackson & D.K.…”

“…Lariat is the result of a cross between the cultivar Red River Runner and US germplasm collection PI 274193, an accession identiied by Damicone et al (2010) (Chenault et al, 2009) and tested for high-oleic oil quality in 2006 to 2007 . F 3 seed positive for both traits was space planted in 2008 in breeding nursery plots at the Oklahoma Agricultural Experiment Station (Caddo Research Station) at Fort Cobb, OK.…”