Physiologic Races of Helminthosporium turcicum in Taiwan

臺灣玉米煤紋病菌之生理小種

葉忠川(C. C. Yeh) ； 蔡阿輝(A. H Tsai)

《中華農業研究》 37卷1期 (1988/03) Pp. 68-75

https://doi.org/10.29951/JARC.198803.0007

摘要

玉米煤紋病(northern leaf blight)是玉米重要的葉部病害，玉米煤紋病菌(Helminthosporium turcicum)在美國報告有三種生理小種(physiologic race)，但本省則未有研究，因此本試驗之目的在探討本省之玉米煤紋病菌的生理小種及其分佈做爲抗病育種之指標，並瞭解目前推廣之玉米栽培品種對各生理小種之抵抗性。於1987年春作，從花蓮之北埔、臺東之關山及瑞和、嘉義之水上、太保與朴子及臺中本所等地採得煤紋病病葉，將不同地點及不同品種／系上之各單一病斑分別處理當做一個菌株，病斑洗淨並陰乾後保存在4℃恒溫箱備用。若再將病葉重新在16℃保持濕潤二天後，病斑表面即會產生大量之分生胞子，以供調配接種源之用。源自單一病斑的每一菌株，可採用本試驗之接種方法在感病品種臺南五號上重複接種數次以增加接種源之量，直到有足量之接種源爲止。供試植物包括表一或表二中所列之判別品種及表三所列之栽培種，均在溫室以盆缽盛土培養至六至七個葉片（約四～五週）時，以花卉栽培用之小型指壓塑膠瓶式噴霧器噴洒各菌株之胞子懸浮液（以含100 μg/ml Tween 80之蒸餾水配製，濃度爲一萬至二萬個胞子／ml），直到葉片表面完全溼潤爲止，接種後之植株在日溫24±10℃夜溫20±1℃之生長箱（白天光照12小時，11,000lux）以透明塑膠袋覆蓋保溼24小時後除去，以後植株可留置在生長箱或者當溫室內之氣溫在28~18℃之間時也可放在溫室內，接種後二週調查及記載病斑形態，大型紡錘形青枯病斑者爲感病(S)反應，小型黃化形病斑者爲抗病(R)反應。表一所列爲文獻上所記載在判別品種上各生理小種之反應，表二爲本研究接種試驗所得之結果，兩者比對即可知本省玉米煤紋病菌之生理小種。結果顯示美國所報告的三種生理小種本省均有存在，而且生理小種之分佈有地域性，本省東部包括花蓮之北埔及臺東之關山與瑞和所採集者均爲Race 1，嘉義之水上、太保及朴子者均爲Race 2，而於本所所採集者均爲Race 3，但試驗中所採集之品種／系並沒有影響生理小種在同一地區內之分佈，亦即在同一地區之不同的品種／系上所獲得之菌株均爲同一生理小種。目前之栽培品種包括臺南五號、臺南選十號、臺南十一號及臺南十六號對主個生理小種均無抵抗性。超甜玉米236號僅抗來自北埔及瑞和之Race 1的某些菌株，對Race 2及3則無抵抗性。臺農351號是目前最具抵抗性之品種，可抗Race 1及3,僅對來自嘉義水上之Race 2的某些菌株表現感病反應。本研究顯示過去本省煤紋病猖獗，乃因栽培品種缺乏抵抗性所致，同時證明栽培抗病品種如臺農351號爲病害防治最經濟而且有效之方法。

並列摘要

Experiments were conducted to identify the races of Helminthosporium turcicum, the northern corn leaf light fungus, and their distribution in Taiwan, and to explore their reaction in the currently grown maize cultivars. Leaf samples of northern leaf blight were collected from various growing areas and varieties/lines in 1987. Inoculum of a single lesion origin was considered an isolate. Several isolates were obtained from each collection site and/or variety/line. According to the reactions of each isolate on the differential varieties, three races of H. turcicum, namely race 1, 2, and 3, the same as in the U. S., were reported for the first time in Taiwan. Race 1 existed in Hualien and Taitung Counties (eastern Taiwan), race 2 in County (southern Taiwan), and race 3 in Taichung Chiayi (central Taiwan), Varieties/lines within a collection site did not influence the distribution pattern of race within that particular area. The grown cultivars Tainan 5, Tainan Selection 10, Tainan 11 and Tainan 16 were all susceptible to the three races. Sweet corn cultivar Honey 236 was susceptible to races 2 and 3 but resistant to some isolates of race 1. Tainung 351, the most resistant cultivar now, is resistant to racs 1 and 3 and only susceptible to a few isolates of race 2 from Chiayi County.