Genetic Diversity and Structure of the Portuguese Pear (Pyrus communis L.) Germplasm

Abstract

A rich heritage of traditional pear varieties is kept in national Portuguese collections. Out of these varieties, "Rocha" dominates national pear production. Although a noticeable phenotypic variation among clones of this variety has been reported, little is known about its genetic variability, as to date molecular studies have been performed on a single "Rocha" clone. Eleven Simple Sequence Repeats (SSR) markers were used to assess the genetic diversity of 130 local cultivars, 80 of them being "Rocha" clones. The results allowed the differentiation of 75 genotypes of which 29 are "Rocha". Three synonyms groups and four homonymous groups of other local varieties were confirmed. A Bayesian model-based clustering approach identified two distinct clusters. Using flow cytometry, six cultivars were found to be triploids. These results show high genetic variability among "Rocha" clones. In conclusion, there is a need for different "Rocha" clones to be preserved to enable the correct selection of the multiplication material.

Genetic Diversity and Structure of Local Pear Cultivars from Mountainous Areas from Aragon (Northeastern Spain)

“…The benefit and need of the genetic identification of pear germplasm banks, improving the management of collections by enabling the identification of duplicates, synonyms, and homonyms, as well as to understand the origins of local varieties, and to ascertain the importance of introgression, polyploidy, and hybridization in their evolution have been widely reported [15,28,30,31,33]. In the last decades, several regional germplasm collections have been promoted in order to face the erosion caused by the introduction of improved varieties in specialized orchards, maintain and preserve the autochthonous diversity.…”

“…Single Sequence Repeats Markers have also been used for this matter [24,25] and have been proven to be a smart choice option because of their transferability, synteny and great conservation [26], as well as their codominance, high polymorphism and ease of application [27], which facilitates result interpretation and ensure reproducibility. In pear, several works have been carried out in different countries to study genetic variability in pear, including modern cultivars and germplasm accessions using SSR markers, such as in Spain [13][14][15]28], Italy [29], Hungary [30], Sweden [31], Bosnia and Herzegovina [32] and Portugal [33,34]. However, there are few studies regarding the genetic diversity in fruit trees located in mountain areas [35][36][37].…”

Phenotypic Diversity of Almond-Leaved Pear (Pyrus spinosa Forssk.) along Eastern Adriatic Coast

“…So far, various Pyrus species have been the subject of scientific research, mostly the economically important taxa such as P. pyraster (L.) Burgsd. [16,[31][32][33], P. communis L. [34][35][36][37][38], P. pyrifolia (Burm.f.) Nakai [39,40], and P. ussuriensis Maxim.…”

Genetic diversity and similarity of pear (Pyrus communis L.) cultivars in Central Europe revealed by SSR markers

“…SSRs have become markers of choice because they are highly informative, reliable, and easy to use for cultivar identification, thereby improving the management of collections by enabling the identification of duplicates, synonyms, and homonyms. They are also valuable tools to understand the origins of local varieties, and to ascertain the importance of introgression, polyploidy, and hybridization in their evolution (Queiroz et al 2019).…”