Developing Triploid (3X) Apomictic Eastern Gamagrass Hybrids.

Eastern gamagrass is a perennial warm-season bunchgrass native from Oklahoma and the Texas pan-handle to the east coast and has long been recognized as a highly productive and palatable forage.  In 2004 a breeding project was initiated to develop a novel set of triploid (3X) true breeding apomictic hybrids with improved agronomic traits for multiple end uses.  WW-1793, a vigorous plant with good general combining ability (GCA) and a carrier of the recessive GSF seed increasing mutation was crossed with 14 other gamagrass genotypes with good GCA and/or putative seed shatter resistance or seed increasing traits.  F1 hybrids that carried the recessive allele were selected using recessive allele specific PCR primers.  The F1 carriers were intercrossed to produce families that segregate for the GSF seed increasing trait in an assortment of genetic backgrounds.  From 2007 – 2008, 41 GSF expressing plants were selected from a spaced plant nursery and used as the female parent in a diploid (2X) x tetraploid (4X) cross to produce triploid (3X) seed.  In 2009, 19010 seed were produced from crossing the 41 GSF parents with 9 tetraploid, apomictic pollen donors, 3331 of which were planted.  In 2009-2010, approximately 1000 putative 3X hybrids were removed from the field and are in the process of being screened for apomictic mode of reproduction and agronomic traits including seed yield.