Physiological Races of Phakopsora pachyrhizi in Taiwan

Abstract

Soybean cvs. Ankur, TK 5, TN4, and P.I.’s 200492 and 230971 are suggested as differentials for race identification of Phakopsora pachyrhizi causing soybean rust in Taiwan. Three races of P. pachyrhizi, based on lesion type, were identified among 50 sngile uredial cultures from soybean leaves collected at five locations in Taiwan. Reaction was determined 14 days after inoculation on intact leaves on plants as well as on detached leaves. The distribution of the three races varied among locations. Common bean, cowpea, hyacinth bean, lima bean, pigeon pea and yam bean also were tested but because no difference in lesion type was observed they were not used as differentials. 從農試所、亞蔬中心、屏東、臺東及花蓮等五個地區之大豆銹病標本，利用離葉法在培養皿內進行接種源之純化與繁殖，每個地區各分得十個單一夏孢子堆來源之菌株，將五十個菌株之夏孢子懸浮液以離葉法分別接種在大豆鑑別品種 Ankur , TKS , TN4 , P . I . 200492 及 P . I . 230971 上，在室內（20-30 ℃ ）經過二星期後，按病斑型可區分為三個生理小種，此三個生理小種在植株上之反應與離葉法者相同，生理小種 1 在所有鑑別品種上產生感病型反應（ TAN ）；生理小種 2 僅在 P . I . 230971 上產生抗病型反應（ RB ），其餘均為感病型；生理小種 3 則僅在 P . I . 200492 上產生感病型反應，其餘為抗病型，此三個生理小種在五個地方之分佈不盡相同，臺東及花蓮未分離到生理小種 1 ；生理小種 2 在五個地區均有發現；生理小種 3 僅在花蓮分離到二菌株。 50 個菌株在菜豆（四季豆）及豆薯上均產生感病型反應，而在豇豆（ cowpea ），鵲豆（ hyacinth bean），皇帝豆（萊豆）及樹豆（P : geon pea ）上均產生抗病型反應，所以沒有被選用為鑑別品種，但在將來的試驗或世界其他地區也許可以利用。