See more from this Session: Graduate Student Poster Competition: Breeding, Physiology and Stress Management
Monday, November 1, 2010
Long Beach Convention Center, Exhibit Hall BC, Lower Level
While SSRs have been considered the marker of choice for their convienence and efficiency, their development is time-consuming and expensive. Even as efforts to develop SSRs specific for turfgrass species have increased in recent years, the robust set of informative markers needed for powerful genetic studies does not exist. By screening a large number of cereal SSR markers, a large pool of such markers can be developed quickly and with little expense. The objectives of this study are to (i) evaluate the transferability of SSR markers developed in two cereal crops to warm-season turfgrass species; (ii) sequence and develop species-specific SSR primers for Zoysia, St. Augustine, and Centipede grasses; (iii) assess the polymorphic rate of SSR markers within and across warm-season grasses. Twenty-seven genotypes represented six turfgrass species including Seashore paspalum, Zoysiagrass (specifically Z. japonica and Z. matrella), Bermudagrass (Cynodon dactylon and C. transvaalensis), Centipedegrass, St. Augustinegrass, and Pembagrass (Stenotaphrum dimidatum Swartz), and tall fescue were evaluated in this study. Genotypes from two major cereal species were chosen to represent maize (Zea mays) and rice (Oryza sativa). One hundred and eighty-eight SSRs maize and rice markers were screened for amplification in eight warm-season and one cool-season turfgrass species. A total of 101 out of 188 (53.7%) maize and rice SSRs amplified in at least one species of turfgrass (46% of maize markers and 62.5% of rice markers). Only 4% (8/188) SSR markers amplified in all nine turfgrass species. On average, 30% of all SSR markers amplified in each individual species. Clear, unambiguous SSR bands were selected and extracted for sequencing in three genotypes: Zoysia japonica cv. Zorro, Centipedegrass PI 414363, and St. Augustinegrass cv. Palmetto in order to design species-specific SSR primers. A set of plant introductions (PIs) of Zoysia grass, Centipedegrass, and St. Augustinegrass were genotyped with these primers. Genetic distances were calculated using NTSYSpc v 2.2 according to Dice and dendograms were constructed using both the unweighted pair group method with arithmetic averaging and the neighbor-joining clustering procedures.