Chickpea (Cicer arietinum L.) contributes 18% of the global production of grain legume and serves as an important source of dietary protein. An important decrease in cropping area and production has been recorded during the last two decades. Several biotic and abiotic constraints underlie this decrease. Despite the efforts deployed in breeding and selection of several chickpea varieties with high yield potential that are tolerant to diseases, the situation has remained the same for the last decade. Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris (Foc) is the major soil-borne fungus affecting chickpeas globally. Fusarium wilt epidemics can devastate crops and cause up to 100% loss in highly infested fields and under favorable conditions. To date, eight pathogenic races of Foc (races 0, 1A, 1B/C, 2, 3, 4, 5 and 6) have been reported worldwide. The development of resistant cultivars is the most effective method to manage this disease and to contribute to stabilizing chickpea yields. Development of resistant varieties to fusarium wilt in different breeding programs is mainly based on conventional selection. This method is time-consuming and depends on inoculum load and specific environmental factors that influence disease development. The use of molecular tools offers great potential for chickpea improvement, specifically by identifying molecular markers closely linked to genes/QTLs controlling fusarium wilt.

A set of 94 peach cultivars including Spanish native peach and foreign commercial cultivars were analyzed using 15 SSR markers, selected for their high level of polymorphism. The number of alleles obtained varied from two to 11 with an average of 6.73 giving 185 different genotypes. All the cultivars showed a unique genetic profile, each one using different genotypic combination of all loci. BPPCT001 was the most informative locus showing also the highest discrimination power. Only six loci allowed the unambiguous separation of all the Spanish native cultivars studied, and the genotypic combination of only eight loci permitted the total differentiation of the 94 peach cultivars analyzed. The six selected loci (BPPCT001, BPPCT006, BPPCT008, PS9f8, UDP98-022, and UDP98-412) seem to be very useful for future Spanish peach identification works, and they will help to establish a molecular data base for native peach cultivars. UPGMA analysis was performed from the genetic distance matrix, and allowed the arrangement of all genotypes according to their genetic diversity. The genetic diversity among cultivars, observed in this work, led to their separation according to their regional origin, their morphological characteristics, and especially according to their fruit traits. Analysis of molecular variance was performed for seven populations from different regions of Spain and USA to examine the distribution of genetic variation of the studied accessions, showing that the major variation occurred within populations in each geographic site. The results reveal the existence of two diversity regions in Spain for peach germplasm.

Twenty microsatellite primer pairs, previously developed in peach, were used to characterize and 23 to explore genetic relationships among 44 clones, representing three groups of rootstocks defined as: (1) Peach-based rootstocks (Prunus dulcis x P. persica, P. persica x P. davidiana); (2) Myrobalan-Marianna plums (P. cerasifera, and interspecific hybrids having P. cerasifera as a parent); and (3) Slow growing plums (P. insititia, P. domestica, and P. domestica x P. spinosa). Eighteen SSR markers, from the 20 initially used, were able to amplify polymorphic products for the Peach-based rootstocks and 13 common markers gave also polymorphism for the Myrobalan-Marianna and Slow growing plums groups. The Dice coefficient of similarity was calculated between all pairs of accessions and their genetic similarity represented by a principal coordinate analysis. The genetic diversity detected among the 44 clones studied divided them in three groups, which are in agreement with their current taxonomic classification and their morphological characteristics. A set of three microsatellites (BPPCT001, CPPCT022 and UDP98-407) can distinguish between all the clones analyzed. The analysis within groups reveal another two sets of three SSR to distinguish between the 35 clones from the peach based rootstocks and the myrobalan-Marianna plums respectively and only a 36 single SSR is needed to distinguish within the clones from the Slow growing plums group. These 37 results demonstrate the high potential of the SSR analysis for peach rootstock identification and 38 studies of diversity in Prunus species. 39 40