Analysis of Genetic Diversity of Spring Durum Wheat (Triticum durum Desf.) Cultivars Released in Russia in 1929–2004

Abstract

Based on genealogical analysis, the genetic diversity of 78 spring durum wheat cultivars released in Russia in have been examined. The temporal trends of change in diversity were studied using series of n × m matrices (where n is the number of the cultivars and m is the number of original ancestors) and calculating coefficients of parentage in sets of cultivars released in particular years. The pool of original ancestors of spring durum wheat cultivars includes 90 landraces and old varieties, more than a half (57%) of which originate from European countries, including Russia and Ukraine (45%). The original ancestors strongly differ in the frequency of presence in the cultivar pedigrees. Landraces Beloturka, Sivouska, Kubanka ( T. durum Desf.), Transbaikalian emmer, Yaroslav emmer ( T. dicoccum Schuebl.), Poltavka ( T. aestivum L.), and the original ancestors of cultivars Kharkov 46, Narodnaya, and Melanopus 1932 enter in the pedigrees of more than half of cultivars created within the framework of various breeding programs. At that, their distribution by cultivars from different breeding centers strongly varies. Analysis of temporal dynamics of genetic diversity, based on genetic profiles and coefficients of parentage, has shown that the genetic diversity of Russian durum wheats increased during the period examined. Nevertheless, genetic erosion of the local material-a loss of approximately 20% of the pool of Russian original ancestors-has been found. The contribution of the original ancestors to the pedigrees of different cultivars, constructed in different breeding centers and recommended for cultivation in different regions, has been estimated. The variation of the released cultivars was highest in the Lower Volga region and lowest in the Ural region. In all, the lower threshold of genetic diversity in all regions does not reach the critical level, corresponding to the similarity of half-sibs. The set of modern cultivars included in the Russian Official List 2004 has a cluster structure. PLANT GENETICS

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“…Pedigree studies have been used in an attempt to overcome some of the problems in assessing diversity based on varieties. Using information on ancestors, these studies estimated the distinctness of cultivars and the extent to which old landraces are present in the pedigree of modern cultivars (Souza and Sorrells, 1989; Dobrotvorskaya et al , 2004; Martynov et al , 2005; Martynov et al , 2006). The calculated diversity indices of groups of cultivars are based on the frequencies of the original ancestors in the pedigrees.…”

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