One Century of Interactions Between Intensive Breeding and Genetic Diversity Conservation of Barley

Abstract

The footprint left by one century of intensive breeding on the phenotype and genotype has been studied in barleys that originated and were developed at the territory of Moravia and south-western Slovakia. The set of barleys (Hordeum vulgare L.) used in retrospective analysis included 106 landraces, obsolete and modern cultivars from the period 1900-2003. The one-hundred year breeding effort resulted to crucial changes of agronomic and technological parameters. The number of spikes m^-2, spike density, protein and starch contents were significantly (P<0.05) different in new barleys (developed after the year 1972). Improvement of malting quality was through decreasing of proteins (average annual decline 0.034% year^-1) and increasing of starch (average annual gain 0.074% year^-1) in grains. Change in genetic diversity has been studied at 27 microsatellite loci with conclusion that nothing adverse happened at these loci during one century of breeding. The oldest barleys were heterogeneous populations, the modern ones were more homogeneous, and moreover introduction of new germplasm within the breeding process has brought new microsatellite alleles. Both, the total number of alleles and average number of alleles per locus indicated that molecular diversity was not reduced by long-term breeding. However, the average number of alleles per genotype pointed to the existence of genetic erosion caused by the gradual replacement of original landraces and local cultivars by modern cultivars. The index of genetic diversity reflected that reduction of genetic diversity from the thirties to the seventies has been turned by breeders in the eighties of the 20^th century.