Syndrome des Basses Richesses – A novel insect transmitted disease in sugar beet.

Abstract

Climate change has hit sugar beet farmers in certain regions of Southern and Eastern Germany and Switzerland with full power. Surprisingly, not only drought related abiotic stress has become a major challenge in these regions but also occurrence of a plant hopper (Pentastiridius leporinus) transmitting a bacterial disease to sugar beet. Plants infected with bacterial species Candidatus Arsenophonus phytopathogenicus, develop a disease called “Syndrome des Basses Richesses” (SBR). SBR infected beet show serious symptoms including leaf yellowing and necrosis, growing of asymmetric, lancet-shaped leaves, browning of tap root tissue but most importantly loss of sugar content up to 5% (abs.) and yield losses up to 25%. With declining sugar prices in SBR affected regions farmers almost fail to keep sugar beet as valuable and profitable part of their crop rotation threatening existence of regional sugar factories. Until now, the plant hopper development cannot be controlled by means of chemical or agronomical plant protection laying a focus on genetic solutions. For SBR resistance breeding KWS has setup various field test locations in Southern and Eastern Germany and a greenhouse test system to examine genotypic variation for effects of SBR infection on sugar yield. A broad range of experimental hybrids is continuously tested for their performance in infected growing areas which will provide KWS varieties with stable and high yields upon SBR infestation in short-term. For long-term solutions and to ensure future breeding gain, we have established a new breeding program to screen for and make use of novel genetic resistance sources against SBR. The program employs most recent means of modern plant breeding including fast breeding cycles, advanced phenotyping, genomic data analysis and holistic variety development. KWS is working with highest priority on providing SBR tolerant sugar beet varieties in the shortest possible time to preserve sugar beet in SBR infested regions.