Development of a Rapid Method Using Oxalic Acid to Assess Resistance Among Hosta Cultivars to Petiole Rot Caused by Sclerotium rolfsii var. delphinii

Abstract

A rapid assay was developed to assess hosta cultivars for resistance to petiole rot caused by Sclerotium rolfsii var. delphinii. Leaves of greenhouse-grown hosta (Hosta kikutii and Hosta spp. cultivars Munchkin, Lemon Lime, Tardiflora, Pearl Lake, Zounds, Gold Drop, Halcyon, and Honeybells) were treated with 20 ml of oxalic acid (50 mM) on a cotton swab, then incubated at 100% relative humidity and 27°C. After 4 days, incidence of leaves with lesions was evaluated. Cultivars Munchkin, Lemon Lime, and Tardiflora had a relatively high incidence of leaves with lesions, whereas Gold Drop and Halcyon had much lower incidence. These results were generally consistent with those of field and greenhouse cultivar screening tests in which whole plants were inoculated with the pathogen and rated for disease incidence. Additional screening methods, including spray application of either oxalic acid or mycelial fragments of S. rolfsii var. delphinii, were not as repeatable or simple to conduct as the cotton swab assay. The cotton swab method showed potential to accelerate identification of highly resistant hosta cultivars, and thereby aid efforts to breed resistance to petiole rot. Accepted for publication 1 December 2008. Published 28 January 2009.

Soybean genotypes resistant to white mold in the field and in oxalic acid sensitivity tests

“…In both this and other field studies (Yang et al, 1999;Hoffman et al, 2002), soybean genotypes exhibited moderate disease resistance combined with high yields. This may be due to the adaptability of the variety to the region and the effect of the expression of genes with quantitative traits on the host plant, which are responsible for modulating the complex resistance of soybean to white mold (Vuong, et al, 2008;Zhao et al, 2015).…”

“…The results of disease assessments in the field indicate that, in addition to precocity (Yang et al, 1999), other traits that confer resistance to white mold interfere in low disease incidence rates, particularly in cultivars from different physiological maturity groups. Environmental conditions are known to affect host physiology.…”

“…delphinii and Hosta sp. plants, Xu et al (2009) developed a rapid selection method to evaluate petiole rot-resistant host plants using oxalic acid as a screening technique under controlled conditions.…”