Scientists Reveal Genetic Maps of Two Distinct Switchgrass Ecotypes

An international consortium of scientists published in the journal Bioenergy Research the first complete genetic maps of switchgrass (Panicum virgatum L.). Switchgrass is a potential biofuel feedstock crop, based on a mapping population derived from a cross between a lowland and an upland ecotype.

Switchgrass is a perennial grass species that has been the target of intensified research since 1992 when the U.S. Department of Energy selected this species as the herbaceous model for its Biofuels Feedstock Development Program. Switchgrass bioenergy research has been geared towards the improvement of its biomass yield and the reduction of recalcitrance - described as the unavailability of sugars trapped in the cellulosic biomass that hinders bioethanol production. Guided by these objectives, an international team of switchgrass researchers embarked on a genetic mapping study to further unlock the many secrets of switchgrass genome. These may hold the keys for both biomass yield and ethanol conversion efficiency.

The published genetic map was generated using a full-sib mapping population derived from a cross between two contrasting cultivars - the lowland ‘Alamo' (AP13) and the upland ‘Summer' (VS16). Comparative analyses between the AP13 and VS16 maps show high colinearity between the two maps with similar marker orders and recombination rates. This suggests that genetic exchanges between the two ecotypes should occur freely and hence genetic improvement through transfer of favorable traits from the higher biomass yielding lowlands into the more cold tolerant uplands and vice versa should be attainable.

The mapped genetic markers will provide useful information not only toward the advancement of switchgrass genome science but more practically for identifying the genes associated with biomass and quality traits for bioenergy utilization.