Spatial and Temporal Assessment of Brassica napus L. Maintaining Genetic Diversity and Gene Flow Potential: An Empirical Evaluation

Abstract

Unpredicted persistence of all forms of B. napus present in the agro-ecosystem is the most common consequence of preservation and self-recruitment of seeds originating from soil seed bank. In nature, spontaneous intra-and inter-specific hybridization of B. napus is possible with sexually compatible species from the Brassicaceae family. The aim of this chapter is (a) to identify the distribution pattern and population dynamics of volunteers and feral populations along statistical regions in Slovenia; (b) to assess the global diversity of naturally appearing B. napus plants; (c) to evaluate the genetic differentiation between volunteers and feral populations; (d) to obtain the spatial and temporal distribution of spontaneous pollination potential and estimation of gene flow conservation; (e) to find the empirically assigned out-crossing rate of B. napus under a fragmented landscape structure, during 4-year monitoring; and (f) to observe that ecologically, evolutionary, and agronomically oriented studies could be conducted at the DNA level using short sequence repeat (SSR) markers. In total, we collected 261 samples of volunteer and feral populations. Our results showed that alleles from both volunteer and feral populations were distributed in three genetic clusters with relatively similar levels of diversity. Naturally occurring out-crossing rate is 13.71%. The global Mantel correlation coefficient of genetic and spatial relatedness between genotypes is 0.044. B. napus originated through spontaneous inter-specific hybridization (followed by polyploidization) between turnip rape (B. rapa L.; genome AA, 2n = 20) and cabbage (B. oleracea L.; genome CC, 2n = 18), resulting in an allotetraploid genome comprising the full chromosome complements of its two progenitors. Spontaneous hybridization between B. rapa and B. oleracea (from Europe and Asia) occurred due to contemporary cultivation of both species in a small geographic area in the Mediterranean region [30].B. napus is a self-pollinated plant species with a variable out-crossing rate, influenced by genotype and environmental conditions. Due to the variable out-crossing rate, intra-and interspecific gene flow may occur in nature [30][31][32]. Inside cultivation areas, the common rate of out-crossing is from 20 to 30% [23]. The out-crossing rate between different varieties with full fertility is up to 0.1% on the field-to-field scale, while in varieties with incorporated male sterility (bait plants; they produce no pollen on their own and represent the worst case scenario on Brassica Germplasm -Characterization, Breeding and Utilization 28

Genetic diversity of Lathyrus sativus L. collection and characteristics of seeds produced in Slovenia and Serbia

“…accessions, a genotyping procedure by Wang et al (2015) was performed using 12 SSR markers (G5, G9, G26, G67, G157, G17922, G18078, G18109, G18308, G18549, G19207, G19337, G15771, G18200, and G17243). The optimal PCR mixtures, applied chemistry, and PCR conditions for each specific marker modifying with M13 label were used as described by Pipan and Meglič (2019); Meglič and Pipan (2018). From the agarose gel results (1,4%; EtBr staining, 100 bp DNA ladder), a binary matrix was performed for the combination of 12 analyzed loci.…”

Brassica biodiversity conservation: prevailing constraints and future avenues for sustainable distribution of plant genetic resources

“…The plant B. napus is highly prone to cross-pollination and spontaneous inter-specific hybridization of B . napus is possible with sexually compatible species ( Meglic and Pipan, 2018 ). To produce pure seeds, Brassica plants need to be grown in isolation and cross-pollination risk reduces with the distance or introducing physical barriers in the flowering plants.…”

“…In case of wind pollination, isolation of plants is very helpful to avoid crosspollination and incase of B. napus outcross could be reduced to less than 4% on separating plants by 120 cm; in oil seed rape almost 10% of pollen could be detected at a distance of even 360 m from the edge of the field; in radish also, the minimal distance for 0% crossing was at least 50 m (Stewart, 2002). The plant B. napus is highly prone to cross-pollination and spontaneous inter-specific hybridization of B. napus is possible with sexually compatible species (Meglic and Pipan, 2018). To produce pure seeds, Brassica plants need to be grown in isolation and cross-pollination risk reduces with the distance or introducing physical barriers in the flowering plants.…”

S-Genotyping and Seed Paternity Testing of the Pear Cultivar ‘Celina’

“…Determining the gene flow within the examined orchards has been simplified by the absence of nearby seed propagated pear trees that could serve as a very diverse set of pollinizers and confound the gene assignment approach. Recent study, which relied on SSR markers to, among other things estimate gene-flow, detected a significant presence of alleles from such feral populations [42]. This is something that needs to be considered when setting up a similar trial.…”