Distribution, diversity and environmental adaptation of highland papaya (Vasconcellea spp.) in tropical and subtropical America

Vasconcellea species, often referred to as highland papayas, consist of a group of fruit species that are closely related to the common papaya (Carica papaya). The genus deserves special attention as a number of species show potential as raw material in the tropical fruit industry, fresh or in processed products, or as genetic resources in papaya breeding programs. Some species show a very restricted distribution and are included in the IUCN Red List. This study on Vasconcellea distribution and diversity compiled collection data from five Vasconcellea projects and retrieved data from 62 herbaria, resulting in a total of 1,553 georeferenced collection sites, in 16 countries, including all 21 currently known Vasconcellea species. Spatial analysis of species richness clearly shows that Ecuador, Colombia and Peru are areas of high Vasconcellea diversity. Combination of species occurrence data with climatic data delimitates the potential distribution of each species and allows the modeling of potential richness at continent level. Based on these modeled richness maps, Ecuador appears to be the country with the highest potential Vasconcellea diversity. Despite differences in sampling densities, its neighboring countries, Peru and Colombia, possess high modeled species richness as well. A combination of observed richness maps and modeled potential richness maps makes it possible to identify important collection gaps. A Principal Component Analysis (PCA) of climate data at the collection sites allows us to define climatic preferences and adaptability of the different Vasconcellea species and to compare them with those of the common papaya

Construction and characterization of two BAC libraries representing a deep-coverage of the genome of chicory (Cichorium intybus L., Asteraceae)

<p>Abstract</p> <p>Background</p> <p>The Asteraceae represents an important plant family with respect to the numbers of species present in the wild and used by man. Nonetheless, genomic resources for Asteraceae species are relatively underdeveloped, hampering within species genetic studies as well as comparative genomics studies at the family level. So far, six BAC libraries have been described for the main crops of the family, <it>i.e</it>. lettuce and sunflower. Here we present the characterization of BAC libraries of chicory (<it>Cichorium intybus </it>L.) constructed from two genotypes differing in traits related to sexual and vegetative reproduction. Resolving the molecular mechanisms underlying traits controlling the reproductive system of chicory is a key determinant for hybrid development, and more generally will provide new insights into these traits, which are poorly investigated so far at the molecular level in Asteraceae.</p> <p>Findings</p> <p>Two bacterial artificial chromosome (BAC) libraries, CinS2S2 and CinS1S4, were constructed from <it>Hin</it>dIII-digested high molecular weight DNA of the contrasting genotypes C15 and C30.01, respectively. C15 was hermaphrodite, non-embryogenic, and <it>S</it>₂<it>S</it>₂for the <it>S</it>-locus implicated in self-incompatibility, whereas C30.01 was male sterile, embryogenic, and <it>S</it>₁<it>S</it>₄. The CinS2S2 and CinS1S4 libraries contain 89,088 and 81,408 clones. Mean insert sizes of the CinS2S2 and CinS1S4 clones are 90 and 120 kb, respectively, and provide together a coverage of 12.3 haploid genome equivalents. Contamination with mitochondrial and chloroplast DNA sequences was evaluated with four mitochondrial and four chloroplast specific probes, and was estimated to be 0.024% and 1.00% for the CinS2S2 library, and 0.028% and 2.35% for the CinS1S4 library. Using two single copy genes putatively implicated in somatic embryogenesis, screening of both libraries resulted in detection of 12 and 13 positive clones for each gene, in accordance with expected numbers.</p> <p>Conclusions</p> <p>This indicated that both BAC libraries are valuable tools for molecular studies in chicory, one goal being the positional cloning of the <it>S</it>-locus in this Asteraceae species.</p

Varieties and breeding

This chapter describes the main and minor cultivars, as well as other species and botanical varieties, of pineapple. The genetics and breeding system, including cytogenetics, selection, and rogueing, are discussed. Considerations in hand pollination, seed handling, germination and nursery management are also mentioned

Varieties and breeding

This chapter describes the main and minor cultivars, as well as other species and botanical varieties, of pineapple. The genetics and breeding system, including cytogenetics, selection, and rogueing, are discussed. Considerations in hand pollination, seed handling, germination and nursery management are also mentioned

Genetic mapping of DNA markers in pineapple

Two genetic maps of DNA-markers (RAPD, AFLP and ISSR) of Ananas comosus var. bracteatus and A. comosus var. comosus have been previously published by our team. These maps were constructed at the Laboratory of Genetics and Plant Breeding of FERN, University of Algarve, using an F1 mapping population derived from a cross performed in Martinique between the two botanical varieties. However, the use of a F1 population, the small size of this population and the use of molecular markers with dominant inheritance allowed only markers that were heterozygous in the parents to be included in those maps and prevented the construction of an integrated high-density map. A new genetic map, intended to cover all the pineapple genome, is currently under construction using a mapping population of 142 F2 plants. This new map will integrate the already published maps and will include markers that had remained unlinked, as they were polymorphic but homozygous in parental genotypes, as well as newly identified markers. At the present time, the new map consists of seven linkage groups (> 40 cM) that integrate markers from both parents, 21 groups (> 40 cM) with markers mostly from one parent, six groups ( 25 cm) with markers from one parent, and 12 smaller (< 25 cM) linkage groups, covering approximately 62% of the pineapple genome

Morphological characterization of pineapple (Ananas comosus) genetic resources from Benin

International audienceIntroduction - The narrow knowledge of the genetic variability in cultivated pineapple in the Republic of Benin and in other West African countries limits its efficient use and its expansion in the international market; it also hinders the efficient development of pineapple while the crop is listed among the top three priority fruit species to be promoted in Africa. Materials and methods - In this study, we assessed pineapple morphological diversity of 55 accessions collected in Benin. Ten qualitative and twenty quantitative traits were used to describe them. Stepwise discriminant analysis and hierarchical cluster analysis were performed to identify quantitative morphological traits which best differentiate accessions and group them into cultivars/morphotypes. Results and discussion - Five pineapple cultivars were identified and characterized for Benin, including 'Smooth Cayenne', 'Baronne de Rothschild', 'Perola', 'Singapore Spanish', and 'Green Spanish'. We observed significant morphological variation among the cultivars. The collected materials were grouped in three clusters based on flowering date, fruit diameter, fruit shelf life, water content, leaf width, fruit weight and the crown height and weight. Correlation analyses between descriptors revealed positive relationships between fruits weight, peduncle diameter, and conicity index in 'Cayenne' and 'Spanish'. Conclusion - This study showed the existence of clear morphological variation among pineapple cultivars which could be used for fruit improvement through clonal selection and farmer training on propagule production and crop homogeneity. 'Singapore Spanish' and 'Green Spanish' could be promoted for their attractive shell color and long shelf life

A genetic map of pineapple (Ananas comosus (L.) Merr.) including SCAR, CAPS, SSR and EST-SSR markers

Despite the paramount importance of pineapple (Ananas comosus L.) in world production and trade of tropical fruits, the genomics of this crop is still lagging behind that of other tropical fruit crops such as banana or papaya. A genetic map of pineapple was constructed using an F2 segregating population obtained from a single selfed F1 plant of a cross A. comosus var. comosus (cv. Rondon, clone BR 50) x A. comosus var. bracteatus (Branco do mato, clone BR 20). Multiple randomly amplified markers (RAPD, ISSR and AFLP) were brought together with SSR and EST-SSR markers identified among sequences uploaded to public databases and with sequence-specific markers (SCAR, SSR and CAPS) derived from random amplified markers. Sixty-three randomly amplified markers (RAPD, ISSR and AFLP) were selected and cloned, resulting in 71 sequences which were used to generate sequence-specific SCAR and CAPS markers. The present map includes 492 DNA markers: 57 RAPD, 22 ISSR, 348 AFLP, 20 SSR, 12 EST-SSR, 25 SCARs, 8 CAPS, and the morphological trait locus "piping", gathered into 33 linkage groups that integrate markers inherited from both botanical varieties, four linkage groups with markers only from var. comosus and three linkage groups with markers exclusively from var. bracteatus. The relatively higher mapping efficiency of sequence-specific markers derived from randomly amplified markers (50.7%) versus SSR (31.4%) and EST-SSR (28.9%) markers is discussed. Spanning over 80% of the 2,470 cM estimated average length of the genome, the present map constitutes a useful research tool for molecular breeding and genomics projects in pineapple and other Bromeliaceae species