Analysis of Hybridization in Korean Ecotypes of Poa pratensis L. Using RAPD and SCAR Markers

Ecotypes of Poa pratensis that exhibit desirable traits as turfgrass such as fast proliferation for ground covering and environmental tolerances were collected in southern Korea. Like most typical varieties of Kentucky bluegrass, the ecotypes had varying levels of apomixis which resulted in low hybridization efficiency. Therefore, experiments were carried out to (1) develop genotype-specific RAPD and SCAR markers, and (2) to determine hybridization rates among the ecotypes and to aid the selection of desirable hybrids. Hybridization among the ecotypes and improved cultivars such as ‘Midnight’, ‘Unique’, ‘Challenger’, ‘Award’, and ‘Blacksburg’ were performed using an in vitro hybridization technique. From 115 crossing combinations among 47 ecotypes and improved cultivars, 8,612 progeny plants were obtained. Desirable progenies were identified in ‘2-73’ which was outstanding in ground covering from a seeded plug as well as its fine texture with darker blue leaf color, and ‘31-40’, which showed relatively early spring green-up. Random Amplified Polymorphic DNA (RAPD) profiles of 27 ecotypes and 5 improved cultivars were examined using OPB primers of 4, 5, 7, 8, 10 and 18, and twenty polymorphic markers were obtained. Sequences for six of the polymorphic RAPD bands were developed into Sequence Characterized Amplified Region (SCAR) markers. The SCAR markers were useful in determining crossing rates between the ecotypes and the improved cultivars used as pollen parents. They were also used to confirm the hybridization of selected progenies like ‘2-73’ (‘P77’ × ‘Midnight’) by the presence of a SCAR marker of the pollen parent.