Interspecific Hybrids between Pembagrass and St. Augustinegrass

Abstract

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.

Pyricularia’s Capability of Infecting Different Grasses in Two Regions of Mexico

“…Fifty-seven Pyricularia isolates were collected from grasses (S. secundatum, C. ciliaris and D. ciliaris) in different locations in Mexico. Pyricularia species have been reported to infect grasses in America [5,6,8,29]. In S. secundatum grass, several Pyricularia isolates, particularly P. oryzae, have been reported to be infecting agents [5].…”

Variation in southern chinch bug (Blissus insularis) survival and damage on St. Augustinegrass germplasm

“…Additionally, PI 289729, which is an accession of pembagrass [ S. dimidiatum (L.) Brongn. ], a wild relative of S. secundatum (Genovesi et al., 2017; Milla‐Lewis, et al., 2013), was included in the study.…”

“…Additionally, PI 289729, which is an accession of pembagrass [S. dimidiatum (L.) Brongn. ], a wild relative of S. secundatum (Genovesi et al, 2017;Milla-Lewis, et al, 2013), was included in the study. Breeding lines were selected based on their overall quality and superior tolerance to abiotic (cold, drought) stresses in North Carolina (data not shown).…”

Performance of diploid and interploid hybrids of St. Augustinegrass under moderate shade

“…(2009) showed the use of embryo‐rescue technology to break sterility barriers and develop interploid (polyploid × diploid) hybrids of St. Augustinegrass (Genovesi, Chandra et al., 2017) and interspecific hybrids between Stenotaphrum dimidiatum (L.) Brongn. (pembagrass) and St. Augustinegrass (Genovesi, Jessup et al., 2017). Several of these hybrids have demonstrated improved drought resistance (Chandra et al., 2015; Meeks & Chandra, 2020) but have not been evaluated for their shade tolerance.…”