Impact of Plant Breeding on the Genetic Diversity of Cultivated Strawberry as Revealed by Expressed Sequence Tag-derived Simple Sequence Repeat Markers

Abstract

<jats:p>Unlike other important crops analyzed so far for genetic diversity and population structure, the brief history and particularities of the genetics of the cultivated strawberry (<jats:italic>Fragaria</jats:italic> ×<jats:italic>ananassa</jats:italic> Duchesne) have limited its genetic characterization. The genomic composition and the pattern of inheritance have not been fully elucidated, although a number of studies have suggested a highly diploidized genome. In this study, the similarity relationships and structure of 92 selected strawberry cultivars with widely diverse origins have been established using simple sequence repeat (SSR) markers derived from expressed sequence tags (EST-SSR markers). Genetic analysis performed by the unweighted pair group method with arithmetic mean clustering revealed a distribution according to both date of cultivar release and breeding for a specific climatic adaptation. Additionally, a model-based clustering approach identified three populations among the strawberry cultivars with an overall F<jats:sub>ST</jats:sub> value of 0.15 to 0.16. Both analyses support a limited differentiation of modern cultivars, most probably as a consequence of the methodology of strawberry breeding. Interestingly, the collection of strawberry cultivars here analyzed showed comparable genetic differentiation to that observed in natural populations of <jats:italic>Fragaria chiloensis</jats:italic> (L.) Mill., one of its wild ancestors. Our results suggest that breeding has produced a small but significant reduction on the genetic diversity of <jats:italic>F</jats:italic>. ×<jats:italic>ananassa</jats:italic>. The panel of 10 EST-SSRs described in this work provided an extremely low probability of confusion (less than 10<jats:sup>−11</jats:sup>), offering an efficient and accurate method for cultivar identification.</jats:p>

Genome-Wide Association Analysis of the Anthocyanin and Carotenoid Contents of Rose Petals

“…The value of heterozygosity is in fact the percentage of polymorphic SNPs; thus, it is not surprising that the value is somewhat lower than that found with 24 SSR markers in garden roses (Vukosavljev et al, 2013). Unlike many other cultivated plant species (Kilian et al, 2007; Gil-Ariza et al, 2009; Wang et al, 2010; Gross et al, 2014), we did not see a reduction over time when we considered the year of release of the variety. This may corroborate observations on the sensitivity of rose for inbreeding depression, which makes selfing unsuitable as a breeding strategy (Pipino et al, 2011).…”

Genetic variation of resistance of the cultivated strawberry to crown rot caused by Phytophthora cactorum

“…As an example, pedigrees of 134 North American cultivars were traced and shown to originate from only 17 cytoplasmic sources [25]. Despite introgressions of wild strawberry germplasm increased initial diversity of the cultivated strawberry, loss of diversity was observed in modern strawberry cultivars [26,27]. However, our results showed that advanced lines can display large variability from high to low level of resistance (Table 5).…”

Allelic Variation ofMYB10is the Major Force Controlling Natural Variation of Skin and Flesh Color in Strawberry (Fragariaspp.) fruit

“…Since cultivated strawberry breeding began in the 1800s using a small number of lines (Darrow, 1966), the diversity of F. ×ananassa has been increased and its genome reshaped by repeated interspecific hybridization with phylogenetically diverse F. chiloensis and F. virginiana accessions (Darrow, 1966;Gil-Ariza et al, 2009;Hardigan et al, 2018;Liston et al, 2014;Hancock, 1999;Bringhurst and Voth, 1984;Hancock et al, 2002;. Introgression of beneficial alleles from these species also results in the accumulation of unfavorable alleles in cultivated strawberry.…”