Levels of intra-specific AFLP diversity in tuber-bearing potato species with different breeding systems and ploidy levels

Authors: BRYAN, GLENN - The James Hutton Institute; MCLEAN, KAREN - The James Hutton Institute; WAUGH, ROBBIE - The James Hutton Institute; Spooner, David

Submitted to: Frontiers in Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2017
Publication Date: 9/21/2017
Publication URL: https://handle.nal.usda.gov/10113/5852195
Citation: Bryan, G.J., McLean, K., Waugh, R., Spooner, D.M. 2017. Levels of intra-specific AFLP diversity in tuber-bearing potato species with different breeding systems and ploidy levels. Frontiers in Genetics. https://doi.org/10.3389/fgene.2017.00119.

Interpretive Summary: Genebanks exist to conserve living plants with the primary goal to make them useful to breeders for crop improvement. There are many ways to study the importance of these genebank collections, one being the relative genetic diversity of different collections. Assessing DNA variation is one such useful method to assess this variation. This study assessed DNA variation using a DNA method technically referred to as Amplified Fragment Length Polymorphism (AFLP), in representative samples of wild and cultivated potato species of differing geographic origin, chromosome levels, and breeding systems. Results confirm the expected considerably lower levels of diversity within accessions of species that can intermated within themselves (self-compatible species) as compared to self-incompatible ones. The most genetically diverse accessions were the two cultivated potato accessions examined, the least diverse being Mexican wild species with three sets of chromosomes technically known as Solanum demissum and Solanum iopetalum. Some purported self-incompatible accessions showed relatively low levels of marker diversity, similar to the more diverse self-compatible material surveyed. Our data indicate that for self-compatible species a single plant is highly representative of a genebank accession. The situation for self-incompatible taxa is less clear, and sampling strategies used will depend on the type of investigation. These data help potato breeders better understand methods to choose diverse collections for their breeding programs if genetic diversity is the primary goal of their selection.

Technical Abstract: DNA-based marker analysis of plant genebank material has become a useful tool in the evaluation of levels of genetic diversity and for the informed use and maintenance of germplasm. In this study we quantify levels of Amplified Fragment Length Polymorphism (AFLP) in representative accessions of wild and cultivated potato species of differing geographic origin, ploidy, and breeding system. We generated 449 polymorphic AFLP fragments in 619 plants from 17 accessions of 14 potato taxa. Intra-accession diversities were compared to those of a synthetic ‘taxon-wide’ population comprising a single individual from a variable number of available accessions of each sampled taxon. Results confirm the expected considerably lower levels of polymorphism within accessions of self-compatible as compared to self-incompatible taxa. Also in accordance with expectation were the broadly similar levels of ‘taxon-wide’ polymorphism among self-compatible and self-incompatible species, with self-compatible taxa showing only slightly lower rates of polymorphism. The most diverse accessions were the two cultivated potato accessions examined, the least diverse being the Mexican allohexaploids Solanum demissum and S. iopetalum. Some purported self-incompatible accessions showed relatively low levels of marker diversity, similar to the more diverse self-compatible material surveyed. Our data indicate that for self-compatible species a single plant is highly representative of a genebank accession. The situation for self-incompatible taxa is less clear, and sampling strategies used will depend on the type of investigation.