Interspecific Hybrids between Pembagrass and St. Augustinegrass
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© Crop Science Society of America. St. Augustinegrass [Stenotaphrum secundatum (Walt) Kuntze] is an important turfgrass throughout many of the warm, humid regions of the world, including the southeastern United States. Unfortunately, the grass is susceptible to a number of insects, pathogens, and nematodes that adversely reduce its desirability as a turfgrass. Another Stenotaphrum species, pembagrass [S. dimidiatum (L.) Brongn.], offers a source of resistance to some of these pests. Crosses were made between pembagrass and St. Augustinegrass in an attempt to transfer desirable resistance genes into St. Augustinegrass. Two pembagrass accessions (PI 289729 and PI 365031) were used as the maternal parents, and different St. Augustinegrass cultivars and breeding lines were used as the paternal parents. Seed from these crosses were small, shriveled, lacking fully developed endosperm, and unable to germinate. A total of 218 embryos were cultured on a growth medium using embryo rescue techniques, and 127 seedlings were recovered. Paternal-specific expressed sequence tag-simple sequence repeat markers were used to identify the hybrids, and all 127 seedlings were determined to be F1 hybrids. These are the first reported hybrids between pembagrass and St. Augustinegrass. The crossability between the two species ranged from 0 to 67.1%, depending on the genotypes used, and the overall mean crossability was 30.8%. Crossability was greatly influenced by which pembagrass genotype was used as the maternal parent. This is an initial step toward introgressing desired genes for insect, nematode, and pathogen resistance from pembagrass into St. Augustinegrass.
author list (cited authors)
Genovesi, A. D., Jessup, R. W., Burson, B. L., Engelke, M. C., & Chandra, A.