Analysis of variability in native populations from South and North America of Pappophorum vaginatum
Lisandro José Entio
Texas A&M University
Rangelands of central Argentina are characterized for the scarcity of warm-season perennial grasses palatable to domestic livestock. Pappophorum vaginatum Buckley is almost the only abundant, C4, palatable forage species in this region, and more specifically, in the South of the Phytogeographical Province of Monte. This species is the only preferred (i.e., desirable) forage perennial grass during the warm-season in central Argentina, which results in forage scarcity for livestock during that season. Learning how to obtain more productive genotypes of this species to incorporate in rangelands, this way maintaining the natural variability, will contribute to increase forage production and increase food for livestock in a sustainable way. As regards the production of P. vaginatum varieties, in the USA only two registered materials were found, whereas in Argentina there is just one material under development phase. Forage germplasm adapted to local conditions is particularly relevant for genetic improvement. Before being implemented, forage germplasm must undergo several assessment stages, from initial characterization and evaluation in greenhouses or fields as isolated plants, to comparative trials of yield and pasture trials. In present days, biotechnological techniques, such as molecular markers, contribute to improved germplasm characterization and could be useful to define genetic local variation. Traditionally, programmes that develop local materials for grasslands have defined ecotypes based on their geographical origin and their morphological and agronomic characters. Hence, it would be relevant to determine genetic differences among USA populations, among Argentina’s populations, and both combined. Also, defining what an ecotype is in genetic terms would be key to accurately develop local germplasm, allowing fewer ecological tradeoffs while still facilitating large scale commercialization and economic seed provision. It would also be useful to verify whether P. vaginatum varieties already designed and implemented in grasslands some years ago still keep their original genetic composition in order to define future selection strategies.