Allelic Variability of Croatian Wheat Cultivars at the Microsatellite Locus Xgwm261

One of the most important characteristics of breeding modern, high-yielding, hexaploid bread wheat cultivars is the utilization of reduced height genes (Rht) or dwarfing genes, which reduces plant height and simultaneously increases adaptability and grain yield potential (Worland et al., 2001). The most frequently used height reducing genes with strong effect on plant height shortening are Rht-B1b (Rht1) and Rht-D1b (Rht2), derived from the Japanese cultivar Norin 10. Although the benefits of Rht-B1b and Rht-D1b are apparent in most environments and were the basis of Borlaug’s Green revolution in wheat breeding, they fail to combine height reductions with grain yield increases in southern European environments (Worland et al., 2001). Cultivars grown in southern Europe also possess short semi-dwarf stem, if controlled by dwarfing genes derived from Japanese cultivars Akakomugi, and in lower scale from cultivar Saitama 27 (Rht-B1d; Rht1) (Worland and Petrović 1988, Jošt and Jošt, 1989, Worland et al., 1998, Ganeva et al., 2005). In cultivar Akakomugi genetic heritage, gene Rht8 and gene Ppd1 for insensitivity to photoperiod are especially important. Because of its tight linkage, gene Rht8 frequently comes together with gene Ppd1, which reduces plant life cycle and has pleiotropic effect on height shortening (Korzun et al., 1998, Worland et al., 2001). Along with gibberellic acid tests in determination of dwarfing genes presence, the development of different molecular markers technique has allowed their direct detection at DNA level. The microsatellite locus Xgwm261 is tightly linked with locus for Rht8 gene at the chromosome region 2DS (distant only 0.6 cM), thus many authors (Korzun et al., 1998, Röeder et al., 1998, Worland et al., 2001, Ganeva et al., 2005, Zheleva et al., ISSN 1330-7142 UDK = 633.11:631.52