Holmes Gerald J, Stange Richard R
Department of Plant Pathology, North Carolina State University, Raleigh 27695.
USDA-ARS, U.S. Horticultural Research Laboratory, Ft. Pierce, FL 34945.
Plant Dis. 2002 Apr;86(4):345-348. doi: 10.1094/PDIS.2002.86.4.345.
Susceptibility of stored sweetpotato roots (cvs. Beauregard and Hernandez) to Rhizopus soft rot caused by Rhizopus stolonifer was tested at 4- to 6-week intervals over a storage period of 335 days in 1998-1999 (year 1) and 1999-2000 (year 2). In each experiment, roots were wounded by four methods (puncture, bruise, broken, and scrape), inoculated with freshly harvested spores from 4- to 10-day-old cultures, and compared with a nonwounded but inoculated control for their susceptibility to decay. Roots were totally resistant to infection after harvest for 60 days in year 1 and 30 days in year 2. The bruise wound type was most commonly associated with infection, with disease incidence peaking 100 and 175 days after harvest in years 1 and 2, respectively. Inoculation by the puncture method followed a similar pattern in Hernandez but was ineffective in Beauregard. Following the peak in disease incidence at 100 or 175 days, susceptibility of roots declined to levels comparable to that of freshly harvested roots. This period of heightened susceptibility was longer in Hernandez than in Beauregard. The effects of injury types broken and scrape were more variable and did not show the same trend in both years.
1998 - 1999年（第1年）和1999 - 2000年（第2年），在335天的储存期内，每隔4至6周测试储存的甘薯根（品种为Beauregard和Hernandez）对匐枝根霉引起的根霉软腐病的易感性。在每个实验中，通过四种方法（穿刺、擦伤、折断和刮伤）对根造成伤口，用4至10日龄培养物中新鲜收获的孢子进行接种，并将其对腐烂的易感性与未受伤但接种的对照进行比较。在第1年收获后60天和第2年收获后30天，根对感染完全具有抗性。擦伤伤口类型最常与感染相关，第1年和第2年收获后疾病发病率分别在100天和175天达到峰值。在Hernandez品种中，穿刺接种方法遵循类似模式，但在Beauregard品种中无效。在100天或175天疾病发病率达到峰值后，根的易感性下降到与新鲜收获的根相当的水平。Hernandez品种的这种易感性增强期比Beauregard品种更长。折断和刮伤这两种损伤类型的影响更具变异性，并且在两年中都没有呈现相同的趋势。
