Vallad Gary E, Bhat Ravi G, Koike Steven T, Ryder Edward J, Subbarao Krishna V
Department of Plant Pathology, University of California, Davis, c/o United States Agricultural Research Station (USARS), Salinas 93905.
Department of Plant Pathology, University of California, Davis, 95616.
Plant Dis. 2005 Mar;89(3):317-324. doi: 10.1094/PD-89-0317.
The seed transmission of Verticillium dahliae was evaluated in lettuce (Lactuca sativa). Seed collected from lettuce plants infected with V. dahliae were plated with or without surface sterilization on Sorenson's modified NP10 medium. Of the seed plated with or without surface sterilization, 90 and 66%, respectively, yielded colonies of V. dahliae. The incidence of Verticillium wilt ranged from 55 to 80% among lettuce plants grown from seed harvested from infected plants. All evaluated isolates of V. dahliae were capable of seed transmission in lettuce. A V. tricorpus isolate failed to cause significant disease in lettuce or to become seedborne. Storage of contaminated seed at seven temperatures ranging from -20 to 15°C for up to 72 weeks did not reduce the incidence of V. dahliae in seed, whereas storage at room temperature (23 ± 2°C) for 20 to 52 weeks reduced the incidence of V. dahliae without affecting seed viability. Of the 11 weed species collected from fields with a known history of Verticillium wilt of lettuce, four yielded V. dahliae. Pathogenicity tests demonstrated that isolates of V. dahliae from Sonchus oleraceus, Capsella bursa-pastoris, and Solanum sarrachoides were as virulent as or more virulent than an isolate of V. dahliae from lettuce. These results demonstrate the potential of seedborne and weedborne inoculum to disseminate V. dahliae.
在生菜（Lactuca sativa）中评估了大丽轮枝菌的种子传播情况。从感染大丽轮枝菌的生菜植株上收集的种子，在经过或未经过表面消毒处理后，接种于索伦森改良NP10培养基上。经过表面消毒处理和未经过表面消毒处理的种子，分别有90%和66%长出了大丽轮枝菌菌落。从感染植株收获的种子所培育的生菜植株中，黄萎病的发病率在55%至80%之间。所有评估的大丽轮枝菌分离株都能够在生菜中通过种子传播。一个三孢轮枝菌分离株在生菜中未能引起显著病害，也未成为种子携带菌。将受污染的种子在-20至15°C的七个温度下储存长达72周，并未降低种子中大丽轮枝菌的发病率，而在室温（23±2°C）下储存20至52周则降低了大丽轮枝菌的发病率，且不影响种子活力。从已知有生菜黄萎病史的田间收集的11种杂草中，有4种长出了大丽轮枝菌。致病性测试表明，来自苦苣菜、荠菜和刺萼龙葵的大丽轮枝菌分离株与来自生菜的大丽轮枝菌分离株一样毒力强或更强。这些结果证明了种子携带和杂草携带接种体传播大丽轮枝菌的可能性。
