Genetic diversity of a germplasm collection of Cucurbita pepo using SRAP and AFLP markers

Abstract

Cucurbita pepo is a highly polymorphic species. The cultivars can be grouped into eight morphotypes in two subspecies, ssp. pepo and ssp. ovifera. A collection of 69 accessions representative of the morphotypes and some unclassified types was used for analysing the morphological and molecular diversity of this species. This collection includes commercial cultivars and Spanish landraces, which represent the great diversification of types that have arisen in Europe after this species arrived from America. For the molecular variability studies, two PCR-based systems were employed, AFLP and SRAP, which preferentially amplify ORFs. Principal coordinates analysis and cluster analysis using the UPGMA method clearly separate the accessions into the two subspecies through the use of both markers. However, the gene diversity and the genetic identity values among morphotypes and subspecies varied between the two marker systems. The information given by SRAP markers was more concordant to the morphological variability and to the evolutionary history of the morphotypes than that of AFLP markers. In ssp. ovifera, the accessions of the different morphotypes were basically grouped according to the fruit colour. This may indicate different times of development and also the extent of breeding in the accessions used. This study has allowed identification of new types that can be employed for the development of new cultivars. The landraces of the spp. ovifera, used as ornamental in Europe, have proved to be of great interest for preserving the diversity of C. pepo.

Combining ability, heterosis, genetic distance and their intercorrelations for waterlogging tolerance traits in chrysanthemum

“…Different methods have been used to evaluate the level of genetic distance, including morphological markers, isozymes and molecular techniques (Weeden and Wendel 1989;Ferriol et al 2003;Smýkal et al 2008). Significant time and effort are required to obtain morphological markers, which are frequently influenced by environmental factors.…”

Genetic diversity of Spanish Cucurbita pepo landraces: an unexploited resource for summer squash breeding

“…This Genebank maintains seed collections of old Winter and Summer squash Spanish cultigens of C.pepo ssp. pepo (Ferriol et al 2003). These were mainly collected from the farmers that still use them for self consumption and/or sale in local markets.…”

“…Most of the studies have been focused on the assessment of the genetic and evolutionary relationships between the wild types and the domesticates, between the two subespecies, and among the cultivar groups, including only a few representatives of European landraces (Ferriol et al 2003;Paris et al 2003).…”

AFLP and SRAP markers linked to the mj gene for root-knot nematode resistance in cucumber

“…Furthermore, sequence polymorphisms were not detected in the parents. Therefore, SRAP markers were used to develop markers since they have 20% codominant characters (Li and Quiros, 2001) and are often used in genetic diversity studies (Budak et al, 2004;Ferriol et al, 2003).…”