Screening of sugar beet pre-breeding populations and breeding lines for resistance to Ditylenchus dipsaci penetration and reproduction

Abstract

Ditylenchus dipsaci is an economically important plant-parasitic nematode affecting European sugar beets. To date, no sugar beet cultivars carrying resistance against D. dipsaci are available to farmers. To find potentially resistant sugar beet lines restricting reproduction and penetration of D. dipsaci, three consecutive in vivo bioassays were carried out. The first experiment determined the penetration rate of D. dipsaci in 79 breeding lines and 14 pre-breeding populations. Based on these results, D. dipsaci penetration and reproduction resistance of eight genotypes was intensively investigated. It could be demonstrated that none of the genotypes showed resistance towards D. dipsaci. However, a high variation of the penetration rate by D. dipsaci was observed among the genotypes. The breeding line ‘DIT_119’ effectively reduced D. dipsaci penetration (34.4 ± 8.8 nematodes/plant at 22 days post-planting) compared to the susceptible control (109.0 ± 16.9) while ensuring a yield comparable to non-inoculated plants. However, the breeding line ‘DIT_119’ did not reduce D. dipsaci reproduction. The paternal line of the cultivar BERETTA KWS, demonstrating a high tolerance to D. dipsaci crown rot symptoms, did not reduce penetration and reproduction. Thus, no correlation can be established between reduced penetration rates, reproduction, and tolerance to D. dipsaci. This study provides an essential basis for the development of resistant sugar beet cultivars to D. dipsaci. The variations observed among genotypes now need to be confirmed with larger-scale screenings.

Virulence and pathogenicity of four Ditylenchus dipsaci populations on sugar beet

“…Later in the growing season, bacterial and fungal pathogens introduced by D. dipsaci engender rotting of the sugar beet crown (Hillnhütter et al, 2011;Kühnhold, 2011;Storelli et al, 2020). To date, no resistant cultivars towards D. dipsaci are available to farmers (Storelli, Minder, et al, 2021b). Leipertz (2007) and Kühnhold (2011) reported evidence for tolerance of sugar beet cultivars toward crown rot.…”

Temporal and species‐specific resistance of sugar beet to green peach aphid and black bean aphid: mechanisms and implications for breeding

“…In accordance with the International Organization for Biological and Integrated Control guidelines on Integrated Production (IOBC IP), 15 the selection of resistant/ tolerant cultivars is necessary if available. Genetic resistance/ tolerance has been identified against various pathogens, including fungal diseases 16,17 and nematodes, like the stem nematode Ditylenchus dipsaci 18 and beet cyst nematode Heterodera schachtii (Schmidt). 19,20 Studies regarding resistance against aphids 21,22 and BYV transmitted by Myzus persicae 23,24 were also conducted.…”

Sugar beet resistance to green peach aphid Myzus persicae (Sulzer) and black bean aphid Aphis fabae (Scop.): Mechanisms and Implications for breeding

“…In accordance with IOBC ip guidelines (Gerowitt et al, 2019), the selection of resistant/tolerant cultivars is necessary if available. Genetic resistance/tolerance has been identified against various pathogens, including fungal diseases (Panella et al, 2008;Scholten et al, 2001) and nematodes, like the stem nematode Ditylenchus dipsaci (Storelli et al, 2021) and beet cyst nematodes Heterodera schachtii Schmidt (Joalland et al, 2018;Wright et al, 2022). Studies regarding resistance against aphids (Lowe, 1974;Lowe & Russell, 1969) and BYV transmitted by M. persicae (Russell, 1966;Schop et al, 2022) were also conducted.…”