Role of residual sexuality in apomictic plants: detection, rate and manifestation in populations of Pilosella (Asteraceae, Lactuceae)
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| Year of publication | 2012 |
| Type | Conference abstract |
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| Description | Contribution of facultatively apomictic maternal biotypes to population diversity was evaluated in seven hybridizing populations of Pilosella in Central Europe, where the apomictic (P. bauhini or P. aurantiaca) and sexual (P. officinarum) biotypes coexist. The parental species were tetraploid (exclusively P. aurantiaca, commonly P. officinarum, rarely P. bauhini), pentaploid (commonly P. bauhini, rarely P. officinarum), or hexaploid (P. officinarum, P. bauhini). Recent hybrids co-occurred with their parental species in all populations. Plants in the field were studied with respect to ploidy level, reproductive system, morphological characters, clonal structure and cp-DNA haplotypes. Identification of those progeny products which had arisen by virtue of residual sexuality in maternal apomicts, was also based on the morphological and reproductive characters in cultivated progeny, that were found different from their maternal parent. Such „aberrant“ progeny had originated either sexually or via haploid parthenogenesis. Structure of progeny arrays generated in the field by facultatively apomictic versus sexual plants, showed that apomictic mothers produced the progeny more variable in ploidy. Apomictic maternal parents formed 2n+n hybrids which had similar reproductive behaviour, producing the polyhaploid, sexual and (usually minority) apomictic progeny in variable rates. Polyhaploids, which were detected among the seed/seedling progeny of apomicts, were not recorded among plants established in the field, suggesting an effect of selection. Residual sexuality in apomicts proved effective also in experimental crosses, giving rise to progeny parallel to spontaneous hybrids from the field. Repeated hybridizations in the field between parental species and/or multi-step crosses can result in advanced hybrid swarms rich in cytotypes and morphotypes. Variation, recorded in such populations, suggests prevailing introgressive hybridization towards sexual species P. officinarum. |
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