Genetic diversity and population structure in the rare Algodones sunflower (Helianthus niveus ssp. tephrodes)


Assessing levels and patterns of population genetic variation is an important step for evaluating rare or endangered species and determining appropriate conservation strategies. This is particularly important for ensuring the preservation of novel genetic variation in wild relatives of crops, which could provide beneficial alleles for plant breeding and improvement. In this study, we evaluate the population genetics of Helianthus niveus ssp. tephrodes (the Algodones sunflower), which is an endangered, wild relative of cultivated sunflower (H. annuus L.). This rare sunflower species is native to the sand dunes of the Sonoran Desert in southern California, southwestern Arizona, and northern Mexico and is thought to harbor beneficial alleles for traits related to drought tolerance. We genotyped nine populations of this species with a set of simple-sequence repeat markers derived from expressed sequence tags (EST-SSRs) and investigated levels of genetic diversity and population structure, in H. niveus ssp. tephrodes. We also compared our results to findings from five related sunflower species that have been analyzed with these same markers, including annuals and perennials that range from rare to widespread. The Algodones sunflower harbors lower levels of standing genetic variation, but similar levels of population structure as compared to other sunflower species. We also discovered that a disjunct population from northern Mexico was genetically distinct from populations elsewhere in the range. Given the occurrence of such a genetically unique population, our recommendations include population surveys of the southern portion of the range in hopes of bolstering the existing germplasm collection. © 2012 Springer Science+Business Media Dordrecht.

Publication Title

Conservation Genetics