Diversity analysis in space and time of an annual selfing species (common bean, Phaseolus vulgaris) and a perennial outcrossing species (cardoon, Cynara cardunculus)
Author(s)
Noorani, Arshiya
Date Issued
February 10, 2011
Type
Doctoral Thesis
Abstract
Evaluating changes in diversity over space and time are key in utilising and conserving biological resources. The aim of this study is to assess diversity in two different species with different breeding systems: in the cardoon a cross-fertilized, perennial and in the common bean a selfing, annual species. The study was designed such that wild types and traditional landraces for each species were obtained from the CIAT, IPK and University of Tuscia seed banks.
A total of 62 bean populations, totalling 498 individuals, were assessed in this study. There were eight wild populations from Latin America, 42 populations from Lazio, Italy, one Italian wild type and 10 Italian bean populations collected in 1950. DNA was extracted from all individuals in the study and amplified using 10 microsatellite markers. Results, based on 26 polymorphic loci, showed that the Lazio population were distinct from the cultivated varieties and from the wild types. The latter two groups of beans, however, were closer to each other than to the modern beans. Levels of polymorphism were high in all populations so that even if the populations from Lazio were different from the 1950 beans, no genetic erosion was found: AMOVA showed 37% diversity among populations and 63% within populations (p<0.000). Morphological data were also analysed through PCA for the Lazio beans. None of the 26 descriptors were significant in ascribing the diversity found, although seed and pod morphometrics were the relevant among the descriptors used.
There were 27 populations of cardoon in the study, of which nine were wild cardoon populations. The cultivated cardoon populations comprised eight European (non-Italian) populations (two of which collected in 1950), one Algerian population, and nine Italian populations. Seeds were obtained, germinated and DNA was extracted and amplified with four ISSR primers. The resulting 398 loci showed that two of the wild populations clustered together, but that there was no clear pattern as to diversity related to geographical origin or year of collection. Levels of polymorphism remained high in this species too, however, such that no genetic erosion was found. The morphological analysis involved data collection in the field and PCA performed. In contrast to the beans, diversity was defined by leaf length, plant height, total number of flowerheads and plant maturity.
Both species showed high levels of intra-varietal diversity, with the traditional varieties not clustering with the wild types. It is therefore possible that introgression has occurred from other sources of germplasm.
Additional information
Dottorato di ricerca in Ecologia e gestione delle risorse biologiche
File(s)![Thumbnail Image]()
Name
anoorani_tesid.pdf
Size
14.16 MB
Format
Adobe PDF
Checksum (MD5)
df169a6ef1d0dcd19d0c754ad5406f72