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Capsicum baccatum is one of the main pepper species grown and consumed in South America. In Brazil, it is commonly cultivated by family farmers, using mostly the genotypes bishop's hat genotypes (locally cambuci) and red chili pepper (dedo-de-moça). This study had the objective of characterizing 116 C. baccatum accessions from different regions of Brazil, based on morphological fruit descriptors and AFLP (Amplified Fragment Length Polymorphisms) markers. Broad phenotypic variability among the C. baccatum accessions was detected when using morphological fruit descriptors. The Ward modified location model (Ward-MLM) discriminated five groups, based mainly on fruit shape. Six combinations of AFLP primers detected polymorphism in 97.93% of the 2466 identified bands, indicating the high genetic variability in the accessions. The UPGMA coincided with the Bayesian clustering analysis and three large groups were formed, separating the wild variety C. baccatum var. praetermissum from the other accessions. There was no relation between genetic distance and geographical origin of the accessions, probably due to the intense exchange of fruits and seeds between farmers. Morphological descriptors used together with AFLP markers proved efficient in detecting the levels of genetic variability among the accessions maintained in the germplasm collections. These results can be used as an additional source of helpful information to be exploited in C. baccatum breeding programs. [ABSTRACT FROM AUTHOR]

Dioecy is a common phenomenon among Atriplex species. However, a mechanism of sex determination has not been determined in this group. We discovered a male-specific RAPD DNA fragment of 2075 bp which was identified with the primer OPAF-14 (5'GGTGCGCACT3') in Atriplex garrettii. The 2075 bp fragment was cloned and sequenced. The DNA sequence of the 2075 bp fragment contains several direct repeats, but no inverted repeats. Two 24-mer oligonucleotype primers which exclusively amplified this fragment were designed and used as SCAR primers. Cytogenetic analysis revealed no apparent heteromorphic chromosome suggesting that sex determination in A. garrettii is genetic, with no evidence of heteromorphic sex chromosomes.

Analysis of chromosome morphology was performed in 23 annual and 31 perennial taxa of Atriplex. The taxa analized were predominantly diploid with 2n = 18 chromosomes. However, tetraploid and hexaploid were also common in both annual and perennial species. While annual Atriplex species were highly variable in their karyotype constitution, perennial species had, comparatively, very uniform chromosome patterns. Differences in chromosome morphology and in haploid chromosome length suggested the presence of interspecific variation for DNA content among annual Atriplex species. Karyotype analysis suggested that perennial Atriplex species have evolved predominantly by centromeric shifts and polyploidy while annual Atriplex species differed by addition and deletion of chromatin associated with structural chromosome changes and polyploidy.

Ophrys iricolor and O. mesaritica are a pair of morphologically similar, closely related sexually deceptive orchids from the eastern Mediterranean. Ophrys iricolor is known to be pollinated by Andrena morio males and the specific pollinator of Ophrys mesaritica is determined as Andrena nigroaenea. Amplified fragment length polymorphism revealed O. iricolor and O. mesaritica to be genetically intermixed on the whole, although populations of O. iricolor and O. mesaritica in geographical proximity are strongly differentiated, suggesting that specific pollinators locally differentiate these taxa. Based on the available biological data and the system of pollinator attraction operative in Ophrys, we hypothesize that O. mesaritica may have arisen from O. iricolor by pollinator shift and that this is more probable than scenarios invoking hybridization as a result of mispollination by rare, non-specific flower visitors or specifically attracted insects. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 583–598. [ABSTRACT FROM AUTHOR]

Presents the findings of a karyotypic study of species of the Serjania and Urvillea genera of the family Sapindaceaea. Characteristics of karyotypes in the genus Serjania; Karyotypic evolution in the genus Urvillea.

• Premise of the study: Hypochaeris is considered a biological model to understand evolutionary processes in the vascular flora of South America, particularly from the temperate portion of the continent. We report the development and characterization of microsatellite markers for H. chillensis to assess the genetic variability and patterns of population structure of the species. • Methods and Results: Twelve microsatellite primers were isolated using a CT- and GT-enriched genomic library. PCR amplification detected one to five alleles, with 2.91 alleles per locus on average. Tested for cross-amplification, all primer pairs were successfully amplified in 10 South American species and in the putative ancestor of the group, H. angustifolia. • Conclusions: The microsatellites can be used to assess genetic diversity and population structure of H. chillensis. Application in other species will focus on the elucidation of adaptive radiation of the genus in South America. [ABSTRACT FROM AUTHOR]

Abstract: This study aims to analyze the diversity of Ty1-copia retrotransposons in 18 taxa of Hypochaeris, including two Old World species H. maculata (2n =2x =10) and H. angustifolia (2n =2x =8), and representatives of the South American species (16 accessions of 15 species; all 2n =2x =8). Analysis of 380 PCR-amplified sequences, corresponding to a conserved domain of the subset of Ty1-copia reverse transcriptase (rt) gene amplifiable with degenerate standard primers, showed high levels of intra- and interspecific heterogeneity. Nucleotide diversity (Pi) of the copia fragments was high in all species and varied from 0.229 (H. angustifolia) to 0.412 (H. chillensis). Higher sequence heterogeneity correlates positively with larger genome size among analyzed species. Phylogenetic analyses of amplified fragments revealed different patterns of intraspecific heterogeneity within species, with most sequences forming one well-supported main clade while a few sequences fall into small clades or are left ungrouped. The combined analysis of all sequences revealed the presence of three main clades and showed that highly diverged species contain closely related Tyl-copia group retrotransposons. One of the main clades includes rt sequences of all South American species and three sequences of their putative ancestor, H. angustifolia, but no sequence of the Old World H. maculata. FISH with copia retrotransposons in four Hypochaeris species, including H. maculata and H. angustifolia and New World H. apargioides and H. spathulata, revealed differences in the chromosomal distribution between the two groups. In Old World species copia retroelements are distributed over the whole length of the chromosomes, excluding rDNA sites and some centromeres. In the South American species the two largest chromosome pairs are enriched in copia, while most of the long arms of the two small pairs of chromosomes are devoid of these elements. The patterns of heterogeneity and chromosomal distribution of Ty1-copia retrotransposons in Hypochaeris are discussed in the context of the origin, genome evolution and organization of the South American species. [Copyright &y& Elsevier]

Parapiptadenia rigida is a tropical early secondary succession tree characteristic of the Tropical Atlantic Rainforest. This species is of great ecological importance in the recovery of degraded areas. In this study we investigated the variability and population genetic structure of eight populations of P. rigida. Five AFLP primer combinations were used in a sample of 159 individuals representing these eight populations, rendering a total of 126 polymorphic fragments. The averages of percentage of polymorphic loci, gene diversity, and Shannon index were 60.45%, 0.217, and 0.322, respectively. A significant correlation between the population genetic variability and the population sizes was observed. The genetic variability within populations (72.20%) was higher than between these (22.80%). No perfect correlation was observed between geographic and genetic distances, which might be explained by differences in deforestation intensities that occurred in these areas. A dendrogram constructed by the UPGMA method revealed the formation of two clusters, these also confirmed by Bayesian analysis for the number of K cluster. These results show that it is necessary to develop urgent management strategies for the conservation of certain populations of P. rigida, while other populations still preserve reasonably high levels of genetic variability.