STUDY OF GENETIC DIVERSITY AND ANALYSIS OF THE DEGREE OF SIMILARITY IN SOME APPLE AND PLUM VARIETIES USING RAPD MARKERS

Molecular evaluation of germplasm is an important step in breeding programs, and the application of molecular biological techniques has led to important results in terms of both within- and between-species variability of traits. The RAPD technique has been successfully used to reveal allelic polymorphism as well as to measure genetic similarity. In this study, the genetic diversity of 25 genotypes and cultivars for apple species and 26 genotypes and cultivars for plum species was assessed with six RAPD markers. All these cultivars belong to the ex situ collection of apple and the ex situ collection of plum at the Research Institute for Fruit Growing Pitesti. The average number of amplified bands was 19.2 for apple and 17.66 for plum. Statistical analysis of intraspecific allelic polymorphism was expressed using the PIC (Polymorphic Information Content) index, which takes into account the allelic frequency. Two statistical indices were used to quantify genetic diversity: the Shannon index and the Simpson index. The degree of similarity between varieties was analyzed using the NTSYSpc version 2.1. Following RAPD analyses, the allele sizes of the analyzed varieties were within the range quoted in the literature, the genetic profiles of the studied varieties suggesting a medium to high genetic diversity, except for markers OPBC-04 and OPBB-05 for plum species, which expressed a high genetic diversity. Genetic distances calculated based on polymorphism of migrated bands in agarose gel confirmed the known genealogies of the apple and plum varieties studied. Thus, the smallest genetic distance for apple species was found between 'Jonagold' and 'Golden Delicious', 'Pionier' and 'Rustic', 'Jonathan' and 'Idared', 'Wagener Premiat' and 'Granny Smith', 'Remar' and 'Aura', 'Romus 3' and 'Rome Beauty', and the largest between Malus floribunda and the other genotypes studied. In plum, the smallest genetic distance was found between 'Dani' and 'Tita', 'Roman' and 'Tuleu gras', 'Dara' and 'Haganta', 'Romanța' and 'Stanley', 'Anna Spath' and 'Renclod Violet', and the largest between 'Lama', 'Black Diamond' and the other genotypes studied.

Pisum elatius in the flora of Bulgaria

At the Northern Black Sea coast – Kaliakra cape and Yailata (Kamen briyag) are identified as two localities of Pisum elatius. Pisum elatius is one of the priority species of wild relatives of grain legumes crops group, more specifically for the cultivated pea (Pisum sativum). The localities are quoted at the flora of Bulgaria and have been confirmed by the team annually for the period 1998 – 2020. Plant morphological description in the flowering phase and bean formation is done and the structure, size and populations vulnerability are described. The differences in the species at both localities are found in the plant's habitus, height and positioning. Seeds from the species have been collected for ex situ collection.

Diversity and Relationships among Neglected Apricot (Prunus armeniaca L.) Landraces Using Morphological Traits and SSR Markers: Implications for Agro-Biodiversity Conservation

Apricot (Prunus armeniaca L.) is an economically important tree species globally cultivated in temperate areas. Italy has an ample number of traditional varieties, but numerous landraces are abandoned and at risk of extinction because of increasing urbanization, agricultural intensification, and varietal renewal. In this work, we investigated the morphological and genetic diversity present in an ex-situ collection of 28 neglected varieties belonging to the so-called “Vesuvian apricot”. Our aim was to understand the level of diversity and the possible link between the promotion of specific fruit types (e.g., by public policies) and the intraspecific variation in apricot. The combination of five continuous and seven categorical traits allowed us to phenotypically distinguish the varieties; while fruit quality-related attributes displayed high variation, both apricot size and skin colour were more uniform. The twelve fluorescent-based Simple Sequence Repeats (SSRs) markers identified cultivar-specific molecular profiles and revealed a high molecular diversity, which poorly correlated with that described by the morphological analysis. Our results highlighted the complementary information provided by the two sets of descriptors and that DNA markers are necessary to separate morphologically related apricot landraces. The observed morphological and genetic differences suggest a loss of diversity influenced by maintenance breeding of specific pomological traits (e.g., skin colour and size). Finally, our study provided evidence to recommend complementary strategies to avoid the loss of diversity in apricot. Actions should pivot on both the promotion of easily identified premium products and more inclusive biodiversity-centred on-farm strategies.

Ex situ conservation of Cistus heterophyllus subsp. carthaginensis (Cistaceae) saves the taxon from introgression by Cistus albidus

Cistus heterophyllus subsp. carthaginensis is a critically endangered plant taxon from E Spain. Only two populations, one in La Pobla de Vallbona, Valencian Community (consisting of only one plant) and the other in Llano de Beal, Cartagena municipality, Autonomous Community of the Region of Murcia, are presently known. The low number of individuals and introgression by the closely related C. albidus are the major threats to the conservation of Cistus heterophyllus subsp. carthaginensis. In the years 2007, 2008, 2011, and 2013 seeds were collected from the Murcia population within the efforts to protect this taxon. In this work, we compare the natural population of Murcia with the ex situ plants originated from the recollected seeds, the only known sample from Valencia, and a specimen of North Africa of C. heterophyllus using genotyping by sequencing. The natural population of Murcia shows clear signals of introgression by C. albidus while the ex situ plants are much less affected, suggesting that the major part of the introgression of the natural populations took place after the specimens for the ex situ collection were taken. The Murcian samples seem not to be very close to the Valencian plant, but the systematic relationships among the studied populations remain unclear. The ex situ conservation efforts are a key to the conservation of this taxon.

Genetic Diversity and Population Structure of Algerian Endemic Plant Species Avena macrostachya Bal. ex Cross. et Durieu

Avena macrostachya is still a relatively unknown species. Using sequence-related amplified polymorphism (SRAP) markers, a simple and inexpensive technique, allowed us to conduct experiments on genetic differentiation and to study the population structure of this Algerian endemic oat. The results obtained showed lower than expected genetic diversity within the A. macrostachya species. The cause may be endemism of the species as well as genetic drift possible during collection, and maintenance of the accessions in gene bank and seed reproduction. No clear genetic structure was found in the examined collection, which indicates a close relationship between the populations collected in the Djurdjura National Park in Algeria. Considering the endemism of the species, its breeding potential and the small-scale ex situ collection, careful monitoring of natural sites and repeating of the collection mission are, therefore, absolutely crucial.

Phenotypic diversity assessment within a major ex situ collection of wild endemic coffees in Madagascar

Background and Aims Like other clades, the Coffea genus is highly diversified on the island of Madagascar. The 66 endemic species have colonized various environments and consequently exhibit a wide diversity of morphological, functional and phenological features and reproductive strategies. The trends of interspecific trait variation, which stems from interactions between genetically defined species and their environment, still needed to be addressed for Malagasy coffee trees. Methods Data acquisition was done in the most comprehensive ex situ collection of Madagascan wild Coffea. The structure of endemic wild coffees maintained in an ex situ collection was explored in terms of morphological, phenological and functional traits. The environmental (natural habitat) effect was assessed on traits in species from distinct natural habitats. Phylogenetic signal (Pagel’s λ, Blomberg’s K) was used to quantify trait proximities among species according to their phylogenetic relatedness. Key Results Despite the lack of environmental difference in the ex situ collection, widely diverging phenotypes were observed. Phylogenetic signal was found to vary greatly across and even within trait categories. The highest values were exhibited by the ratio of internode mass to leaf mass, the length of the maturation phase and leaf dry matter content (ratio of dry leaf mass to fresh leaf mass). By contrast, traits weakly linked to phylogeny were either constrained by the original natural environment (leaf size) or under selective pressures (phenological traits). Conclusions This study gives insight into complex patterns of trait variability found in an ex situ collection, and underlines the opportunities offered by living ex situ collections for research characterizing phenotypic variation.