臺灣草莓種原對炭疽病菌之抗性篩檢

Screening of strawberry germplasm in Taiwan for resistance to Colletotrichum spp.

草莓炭疽病為嚴重危害草莓之真菌性病害，其病原菌為Colletotrichum spp.，可感染草莓全株，在各個生長期皆能造成危害。臺灣田間炭疽病菌族群以C. siamense為主（佔75%），C. fructicola次之（佔11%）。'桃園1號'為臺灣草莓主流栽培品種之一，然其對炭疽病菌十分感病，產業上對於具有良好園藝性狀又抗（耐）病的新品種有殷切需求。國內草莓種原保存於桃園區農業改良場五峰工作站及苗栗區農業改良場生物防治分場。為釐清種原對炭疽病菌之抗性，且為減少走蔓苗材料消耗，本研究建立可同時評估葉部炭疽病及冠腐病的接種系統。以本土高致病力代表菌株C. siamense ML133及C. fructicola ML356接種種原庫中的55個品種（系），其中14個品種（系）之葉部抗性較佳，兩菌株接種之葉部罹病面積率均小於10%，顯著低於感病對照品種'桃園1號'接種ML133之42.4%；7個品種（系）之冠部罹病面積率小於20%，但只有'TYS16109'（兩菌株接種皆小於10%）與'桃園1號'接種ML133（53.5%）有顯著差異。同一菌株在葉部與冠部造成之罹病程度並無顯著相關（ML133為r = 0.23, p = 0.112；ML356為r = 0.06, p = 0.686）。本研究篩選出具良好之葉部抗性且冠部罹病率在20%以下之'TS4'、'Rassen'、'TS13'、'久留米103'及'TYS16109'等品種（系），尤其'TYS16109'兼具良好之葉 部與冠部抗性，皆可作為未來選擇抗病育種親本之參考。

Anthracnose, caused by Colletotrichum spp., is a devastating disease to strawberry. The pathogen can infect the whole strawberry plant at all growth stages. The predominant Colletotrichum spp. causing strawberry anthracnose in Taiwan are C. siamense and C. fructicola that account for 75% and 11%, respectively. 'Taoyuan no.1', one of the most popular strawberry cultivars in Taiwan, is highly susceptible to anthracnose. New cultivars with desirable horticultural traits and high resistance (tolerance) to diseases are in high demand. Strawberry germplasm resources in Taiwan are preserved in Wufong Branch Station at Taoyuan District Agricultural and Research Extension Stations and Biological Control Branch at Miaoli District Agricultural and Research Extension Stations. To understand the resistance/susceptibility of the strawberry cultivars/ lines in the germplasm, with the consideration of reducing the consumption of experiment seedlings, we established an inoculation system which allows simultaneous evaluation of anthracnose leaf blight and crown rot. Total 55 cultivars/lines were inoculated with two domestic highly pathogenic representative isolates - C. siamense ML133 and C. fructicola ML356. High level of leaf resistance was observed from 14 cultivars/lines. Their percentages of disease leaf area were less than 10%, which was significantly lower than the susceptible control 'Taoyuan no.1' inoculated with ML133 (42.4%). Seven cultivars/lines showed less than 20% of diseased crown area, but only 'TYS16109' (< 10% for inoculations of both isolates) was significantly different from 'Taoyuan no.1' inoculated with ML133 (53.5%). No significant correlation was observed between the degrees of disease in leaves and crowns caused by the same isolate (ML133: r = 0.23, p = 0.112; ML356: r = 0.06, p = 0.686). According to the inoculation tests in this study, 'TS4', 'Rassen', 'TS13', '久留米103' and 'TYS16109' showed good leaf resistance and less than 20% of diseased crown area. In particularly, 'TYS16109' exhibited high level of both leaf and crown resistance. These cultivars/lines can be used as parental lines for resistance breeding in the future.