Abstract
In angiosperms, gametophytic apomixis (clonal reproduction through seeds) is strongly associated with polyploidy and hybridization. The trait is facultative and its expressivity is highly variable between genotypes. Here, we used an F1 progeny derived from diploid apomictic (aposporic) genotypes of Paspalum rufum and two F2 families, derived from F1 hybrids with different apospory expressivity (%AES), to analyze the influence of the environment and the transgenerational transmission of the trait. In addition, AFLP markers were developed in the F1 population to identify genomic regions associated with the %AES. Cytoembryological analyses showed that the %AES was significantly influenced by different environments, but remained stable across the years. F1 and F2 progenies showed a wide range of %AES variation, but most hybrids were not significantly different from the parental genotypes. Maternal and paternal genetic linkage maps were built covering the ten expected linkage groups (LG). A single-marker analysis detected at least one region of 5.7 cM on LG3 that was significantly associated with apospory expressivity. Our results underline the importance of environmental influence in modulating apospory expressivity and identified a genomic region associated with apospory expressivity at the diploid level.
Highlights
IntroductionA small proportion of seed plants are able to avoid meiosis and fertilization, to produce seeds identical to their maternal parent, by apomixis [1,2]
We report that apospory expressivity is influenced by the environment in both diploid and tetraploid genotypes of P. rufum
This is an important aspect to be considered for future application of apomixis technology and its introduction into sexual species
Summary
A small proportion of seed plants are able to avoid meiosis and fertilization, to produce seeds identical to their maternal parent, by apomixis [1,2]. This natural reproductive system owns great agronomic importance as it allows hybrid combinations to be perpetuated without the need to repeat the original crosses every season. It accelerates breeding programs and enables seed propagation of crops reproduced vegetatively [1,2]. Apomictic plants are potentially a constant source of renewable seeds, which would be of great advantage for crop production, especially for developing countries, if their uses became freely available to the public and private sectors [3,4]
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