In vitro response of strawberry cultivars and regenerants to Colletotrichum acutatum

Abstract

Diseases affecting strawberry (Fragaria  ananassa Duch.) have been of major concern in recent years because of their widespread occurrence and potential for yield loss. Anthracnose, caused by the fungus Colletotrichum acutatum, is one of the most serious diseases of strawberry worldwide. Tissue-culture induced (somaclonal) variation provides one strategy for generating disease-resistant genotypes. As part of a program to generate strawberry germplasm resistant to anthracnose, an in vitro screening system was used to evaluate several commercial cultivars, Chandler, Delmarvel, Honeoye, Latestar, Pelican and Sweet Charlie propagated in vitro, and shoots regenerated from leaf explants of these cultivars for resistance to C. acutatum isolate Goff (highly virulent). Regenerants with increased levels of resistance were identified from all of the cultivars. The greatest increases in disease resistance were observed for regenerants from leaf explants of cultivars Pelican and Chandler that exhibited 17.5-and 6.2-fold increases in resistance, respectively. The highest levels of anthracnose resistance (2 to 6% leaf necrosis) were exhibited by regenerants from explants of cultivars Pelican and Sweet Charlie. These studies suggest that generating somaclonal variation may be a viable approach to obtaining strawberry plants with increased levels of anthracnose resistance.

Sensibilidad de aislados de Colletotrichum acutatum obtenidos de fresa a los fungicidas metil tiofanato y azoxystrobin

“…Resistant varieties and biological control have also been used (Wharton and Diéguez-Uribeondo, 2004;Hammerschlag et al, 2006). Although preventive fungicides, such as Captan, Thiram, and different copper-based formulations, are the most frequently used, and other fungicides with specific mode of action, such as cyprodinil+fludioxonil, pyraclostrobin, azoxystrobin and thiophanate methyl, are often used as well (Turechek et al, 2006;Wedge et al, 2007).…”

Breeding of Japanese butterbur (Petasites japonicus) by using flowerhead culture

“…Selection of somaclonal variants has successfully been used to generate cultivars in a number of plants, including apple (Donovan et al 1994), banana (Cote et al 1993), celery (Heath-Pagliuso et al 1988), cucumber (Burza and Malepszy 1995;Filipecki et al 2005), garlic (Novak et al 1982), lettuce (Engler and Grogan 1984), peach (Hammerschlag 1990), strawberry (Swartz et al 1981;Toyoda et al 1991;Takahashi et al1992;Hammerschlag et al 2006), and tomato (Evans and Sharp 1983;Barden et al 1986). Although it is important to use a regeneration method that results in a high frequency of somaclonal variation in the regenerated plants so as to efficiently select useful somaclonal variants (Ezura et al 1995), in Japanese butterbur, it was difficult to control the high frequency occurrence of undesirable variation, which was observed in the regenerants from callus cultures (Morishita 1991).…”

Stability of Verticillium dahliae resistance in tissue culture-derived strawberry somaclones

“…Somaclones with enhanced resistance to Phytophthora cactorum (Battistini, Rosati 1991), Fusarium oxysporum f.sp. fragariae (Toyoda et al 1991) and Colletotrichum acutatum (Hammerschlag et al 2006) were selected and tested. Other useful traits derived from somaclonal variants include plant vigour, fruit yield and fruit colour (Fukuoka et al 1996;Popescu et al 1997;Biswas et al 2009).…”