Germination and field establishment of Indiangrass populations selected for greater laboratory seed germination in a simulated dry condition

Rapid seed germination followed by rapid seedling establishment are important traits for field establishment of grasses under variable climatic conditions. This research was designed to improve the seed germination of three Indiangrass [Sorghastrum nutans (L.) Nash] populations through two cycles of recurrent selection and to field test the nine populations. Two cycles of recurrent selection were used to develop C-1 and C-2 populations from three previously unselected populations of Indiangrass. Cycle 1 consisted of germinating 3,500 open-pollinated seeds of each C-0 population in water of -0.8 MPa potential for 7 d. All germinated seeds within 7 d were selected to create three C-1 populations. Cycle 2 selection was like Cycle 1, except that C-1 populations were used to develop three C-2 populations. To test the effects of selection, four 50-spikelet samples of the nine Indiangrass populations were germinated in water of -0.8 and 0 MPa potentials for 7 d for two seed harvests. Both water potentials produced a population x selection generation interaction (P <= .05). Different rates of gain among the Indiangrass populations for water potential treatments (-0.8 and 0 MPa) described the interactions. On average, C-1 and C-2 populations emerged and survived better than C-0 populations in the field. Thus, the data suggest that recurrent selection for increased laboratory seed germination of Indiangrass in a low water potential not only improved the 7-d laboratory seed germination, but seed mass and stand establishment as well.