Molecular characterization of almond accessions from the island of La Palma (Canary Islands, Spain) using SSR markers

Abstract

In this study, 15 simple sequence repeat (SSR) markers were used for genetic diversity analysis of 45 almond accessions, which included 25 local cultivars from La Palma Island and three other commercial cultivars. A total of 110 amplification fragments were produced, with an average value of 7.9 alleles per locus. Twelve of the SSR markers can be considered as highly informative, with values of expected heterozygosity and power of discrimination above 0.5 and 0.8, respectively. Due to cases of synonymy and homonymy, 37 different genetic profiles were obtained, with the homonymy of the soft-shell varieties known as 'Mollar' being the most significant. Cluster analysis identified four groups within the accessions. One of these groups exclusively consisted of the two commercial cultivars 'Guara' and 'Ferraduel'. The other commercial cultivar used in the study, 'Desmayo Largueta', was in a cluster with three cultivars from the same locality. The analysis of molecular variance revealed that the within-localities component accounts for most of the total variation, suggesting that La Palma almond cultivars did not originate independently in different parts of the island. The results of the study reveal the genetic singularity of La Palma almond cultivars and the genetic diversity among them.

Genetic Diversity of Local Peach (Prunus persica) Accessions from La Palma Island (Canary Islands, Spain)

“…Both NJ and STRUCTURE analyses showed a close relationship between La Palma and Spain mainland samples, which suggested the main origin of La Palma samples from the Iberian Peninsula. Similar results were obtained for other fruit tree species for which genetic diversity in La Palma was studied and compared to that in Spain, like almond [50], apple [51], chestnut [52], apple [53], or grapevine [54]. The rest of the accessions from La Palma that grouped in other clusters could be due to more recent plant introductions.…”

Morphological and Molecular Characterization of a New Self-Compatible Almond Variety

“…The use of SSR markers for the genotyping of almond varieties and their relatives is well established in the literature [15][16][17][18][61][62][63][64][65][66][67][68]. The great sample variability in these reports does not allow a comparison of diversity indices with the values of the current study.…”

Positioning Portugal in the Context of World Almond Production and Research

“…Currently, almond cultivation relies on a small number of highly productive cultivars. However, almond germplasm is composed of thousands of accessions that show great variability in terms of adaptation to different soil and climate conditions, resistance to biotic and abiotic stress and almond quality characteristics [71][72][73][74][75][76][77][78]. The self-incompatibility of most almond cultivars, coupled with the extensive use of seeds for propagation, has played an important role in differentiating the vast genetic diversity within the species [74,75].…”

“…As said before, self-incompatibility of most almond cultivars coupled with the extensive use of seeds for propagation plays an important role in the vast genetic diversity observed within this species [74,75]. Several research works have used simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) molecular markers to study the genetic diversity and relatedness of numerous accession and cultivars from Spain [77][78][79], Italy [80][81][82], Iran [83] Australia and the United States of America [84,85]. All these works evidence that the geographical diversity of the accessions of the studied collections is reflected on their genetic diversity.…”