Association of sugarcane cold tolerance with stem borer resistance.

Louisiana is among the coldest sugarcane-growing locations in the world, requiring the use of cold tolerant cultivars to prevent degradation of sugar content following freezes. The most damaging pests in this system are the sugarcane borer (SCB, Diatraea saccharalis) and the Mexican rice borer (MRB, Eoreuma loftini). Both borers and cold damage are managed, in part, with resistant cultivars, with prior work indicating potential "cross-tolerance". We reviewed the literature on commercial cultivars then used multivariate methods to assess the strength of this association, the interaction with genetics (using SSR markers), and associations with fiber, theoretically recoverable sucrose (TRS), and tonnage. SCB larval survival and weight gain were also assessed on diets from cultivars with different cold tolerance and borer resistance. Both SCB and MRB resistance were associated with good cold tolerance, but this was not mediated by fiber, TRS, or tonnage. There was no strong genetic clustering with borer resistance or cold tolerance. Further, SCB larval survival and performance did not differ among cultivar diets. These data indicate that breeding for both borer resistance and cold tolerance may be possible given the robust relationship between them. However, further evaluation of potential mechanisms and genetic linkages is required.