Efficient Screening Method for Resistance of Cucumber Cultivars to <em>Fusarium oxysporum f. sp. cucumerinum</em>

Research in Plant Disease 2014;20(4):245-252.
Published online December 15, 2014.

오이 덩굴쪼김병에 대한 효율적인 저항성 검정 방법

이지현¹ · 김진철² · 장경수¹ · 최용호¹ · 최경자^1*

¹한국화학연구원 바이오화학연구센터, ²전남대학교 응용생물공학부

Efficient Screening Method for Resistance of Cucumber Cultivars to Fusarium oxysporum f. sp. cucumerinum

Ji Hyun Lee1, Jin-Cheol Kim2, Kyoung Soo Jang1, Yong Ho Choi1 and Gyung Ja Choi1*

¹Research Center for Biobased Chemistry, Korea Research Institute of Chemical Technology, Daejeon 305-600, Korea
²Division of Applied Bioscience and Biotechnology, Institute of Environmentally-Friendly Agriculture, Chonnam National University, Gwangju 500-757, Korea

Correspondence: <p>Ji Hyun Lee Tel : +82-42-860-7434 Fax: +8,

Gyung Ja Choi

Tel : +82-42-860-7434
Fax: +82-42-861-4913
E-mail: kjchoi@krict.re.kr

Received: September 03, 2014 Revised: September 23, 2014 Accepted: October 31, 2014

Abstract

The study was performed to establish an efficient screening method for resistant cucumber to Fusarium oxysporum f. sp. cucumerinum. The isolate KR5 was identified as F. oxysporum f. sp. cucumerinum based on molecular analyses of ITS and TEF genes and host-specificity test on cucurbits including melon, oriental melon, cucumber, and watermelon. Then four cucumber and two rootstock cultivars showing different resistance degrees to the Fusarium wilt pathogen KR5 were selected. And development of Fusarium wilt of the six cultivars according to several conditions, including incubation temperature after inoculation, inoculum concentration, root wounding, and growth stages of seedlings, was investigated. Disease severity of Fusarium wilt on the resistant cultivars was changed with incubation temperatures after inoculation. The resistant cultivars showed the higher resistance when inoculated plants were kept at 25 or 30°C than at 20°C. Among four different growth stages of the seedlings, seven-day-old seedling represented the most difference of resistance and susceptibility to Fusarium wilt. From above results, we suggest that an efficient screening method for resistant cucumber to F. oxysporum f. sp. cucumerinum is to dip the non-cut roots of seven-day-old seedlings in spore suspension of 1.0 × 10⁶-1.0 × 10⁷ conidia/ml and to transplant the seedling into a non-infected soil, and then to incubate the inoculated plants in a growth room at 25°C for 3 weeks to develop Fusarium wilt.

Key Words: Breeding, Disease resistance, Fusarium wilt, Resistant screening