Breeding for Reduced Post‐Harvest Seed Dormancy in Switchgrass: Registration of TEM‐LoDorm Switchgrass Germplasm

The switchgrass (Panicum virgatum L.) germplasm line TEM‐LoDorm (Reg. No. GP‐98, PI 636468) was developed by the USDA‐ARS in cooperation with the Texas Agricultural Experiment Station and was released in May 2007. TEM‐LoDorm has reduced post‐harvest seed dormancy and was developed to provide breeders with a germplasm source to improve germination and stand establishment. The cultivar Alamo was used as a base population, and TEM‐LoDorm was developed using four cycles of recurrent selection. During the first three cycles, recently harvested seed from about 200 entries were germinated to evaluate immediacy of germination. Seedlings from seed that germinated within 3 to 14 d were used to establish a polycross nursery to produce seed for the next cycle of selection. Twenty‐four plants in the cycle 3 crossing block that produced seed with the most rapid germination rate were dug and used to establish cycle 4 crossing blocks. Over a 2‐yr period, germination of recently harvested seed from most of these 24 plants was significantly (P < 0.05) higher than seed from unselected Alamo; some plants were 10 or more times higher than Alamo. Equal quantities of seed from these 24 plants were bulked to constitute TEM‐LoDorm germplasm.