Epsilon Archive for Student Projects

Abstract

Over the past two decades Swedish oilseed rape production has increased significantly, primarily due to the introduction of new and improved varities and increase in profitability. This crop has become a crucial component of both food and feed production. Climate change poses new challanges for crop production. Altough blackleg, caused by the two fungal pathogens Plenodomus lingam and Plenodomus biglobosus, is not a new disease in Sweden, it is expected to thrive in a warmer climate. The two pathogens coexist in the oilseed rape plant and share most of the life cycle, and it is the differences in their life cycles that allow them to coexist. They differ in the appearance of symptoms, with P. lingam causing the more severe stem canker and P. biglobosus causing less severe stem lesions. This study aimed to investigate the presence of P. lingam and P. biglobosus in Swedish winter oilseed rape and to investigate whether the presence of disease symptoms correlate with the molecular detection of the pathogens. Stem samples of four varieties of winter oilseed rape were collected in summer July 2023 from the Rural Economy and Agricultural Societies' field trial in Skåne. Two of the varieties carried the blackleg resistance gene Rlm7. Disease score was made on the cross section and the surface on the base part and on the upper part of the stem. The presence of the two pathogens were then quantified using a species-specific ddPCR assay. The results showed that both P. lingam and P. biglobosus are present in Swedish oilseed rape fields and that the prevalence differ among varieties. The results aslo showed that P. lingam dominates in the basepart and the upper part of the stem. The number of gene copies for P. lingam are equal between the upper part and the base part, and the same applies to P. biglobosus. This contradicts the theory that, P. biglobosus should mainly be found in the upper part of the stem. Further, the proportion between the two species changes between the autumn and the summer. Both in the autumn and in the summer P.lingam was dominating over P.bigobosus and was on a high level while P. bigobosus inceres in the summer compared to the autumn. Furhermore, high incidence and severity of blackleg in the fall negatively affects the yield.

Over the past two decades Swedish oilseed rape production has increased significantly, primarily due to the introduction of new and improved varities and increase in profitability. This crop has become a crucial component of both food and feed production. Climate change poses new challanges for crop production. Altough blackleg, caused by the two fungal pathogens Plenodomus lingam and Plenodomus biglobosus, is not a new disease in Sweden, it is expected to thrive in a warmer climate. The two pathogens coexist in the oilseed rape plant and share most of the life cycle, and it is the differences in their life cycles that allow them to coexist. They differ in the appearance of symptoms, with P. lingam causing the more severe stem canker and P. biglobosus causing less severe stem lesions. This study aimed to investigate the presence of P. lingam and P. biglobosus in Swedish winter oilseed rape and to investigate whether the presence of disease symptoms correlate with the molecular detection of the pathogens. Stem samples of four varieties of winter oilseed rape were collected in summer July 2023 from the Rural Economy and Agricultural Societies' field trial in Skåne. Two of the varieties carried the blackleg resistance gene Rlm7. Disease score was made on the cross section and the surface on the base part and on the upper part of the stem. The presence of the two pathogens were then quantified using a species-specific ddPCR assay. The results showed that both P. lingam and P. biglobosus are present in Swedish oilseed rape fields and that the prevalence differ among varieties. The results aslo showed that P. lingam dominates in the basepart and the upper part of the stem. The number of gene copies for P. lingam are equal between the upper part and the base part, and the same applies to P. biglobosus. This contradicts the theory that, P. biglobosus should mainly be found in the upper part of the stem. Further, the proportion between the two species changes between the autumn and the summer. Both in the autumn and in the summer P.lingam was dominating over P.bigobosus and was on a high level while P. bigobosus inceres in the summer compared to the autumn. Furhermore, high incidence and severity of blackleg in the fall negatively affects the yield.