Browsing by Author "Garcia-Gonzales, Rolando"

Now showing 1 - 6 of 6
  • No Thumbnail Available
    Item
    Descriptive Genomic Analysis and Sequence Genotyping of the Two Papaya Species (Vasconcellea pubescens and Vasconcellea chilensis) Using GBS Tools
    (2022) Carrasco, Basilio; Arevalo, Barbara; Perez-Diaz, Ricardo; Rodriguez-Alvarez, Yohaily; Gebauer, Marlene; Maldonado, Jonathan E.; Garcia-Gonzales, Rolando; Chong-Perez, Borys; Pico-Mendoza, Jose; Meisel, Lee A.; Ming, Ray; Silva, Herman
    A genotyping by sequencing (GBS) approach was used to analyze the organization of genetic diversity in V. pubescens and V. chilensis. GBS identified 4675 and 4451 SNPs/INDELs in two papaya species. The cultivated orchards of V. pubescens exhibited scarce genetic diversity and low but significant genetic differentiation. The neutrality test yielded a negative and significant result, suggesting that V. pubescens suffered a selective sweep or a rapid expansion after a bottleneck during domestication. In contrast, V. chilensis exhibited a high level of genetic diversity. The genetic differentiation among the populations was slight, but it was possible to distinguish the two genetic groups. The neutrality test indicated no evidence that natural selection and genetic drift affect the natural population of V. chilensis. Using the Carica papaya genome as a reference, we identified critical SNPs/INDELs associated with putative genes. Most of the identified genes are related to stress responses (salt and nematode) and vegetative and reproductive development. These results will be helpful for future breeding and conservation programs of the Caricaceae family.
  • No Thumbnail Available
    Item
    Genetic diversity and population structure of Chilean blueberry Gaultheria pumila (L.f.) DJ Middleton (Ericaceae)
    (2020) Pico-Mendoza, Jose; Garcia-Gonzales, Rolando; Quiroz, Karla; Pinoargote, Miryan; Rodriguez-Alvarez, Yohaily; Chong, Borys; Caceres-Ruz, Pablo; Pino, Hugo; Caligari, Peter D. S.; Carrasco, Basilio
    Gaultheria pumila (L.f.) D.J. Middleton is a native shrub of Chile that produces edible berry fruits. This species is related to the cultivated Vaccinium species; for this reason it is currently called Chilean blueberry locally. Although G. pumila has important attributes, it has been largely ignored, and remains an unexplored genetic resource. This study investigates the genetic diversity to support the efforts to domesticate the species. Sampling was carried out in 11 sites collected from four Regions of Chile. In total, 160 individuals were collected and analyzed using a set of 10 simple sequence repeats (SSRs) markers. The average observed heterozygosity was Ho = 0.50, while the expected heterozygosity was He = 0.46. The fixation index (F-IS) showed an average of -0.07, and the proportion of differentiation among populations (F-ST) was 0.11. The average level of polymorphic loci in all populations (PPL) was 96.97%. AMOVA showed that the genetic diversity among populations was very low (Phi PT = 6%). Significant correlations were found between genetic and geographic distance. Multivariate and Bayesian analyses identified two genetic groups. These results will be very useful to support the efforts to domesticate and increase the value of this species.
  • No Thumbnail Available
    Item
    Heterogeneous genetic structure in a natural population of Rauli (Nothofagus nervosa)
    (2011) Carrasco, Basilio; Eaton, Lafayette; Letelier, Luis; Diaz, Carole; Garcia-Gonzales, Rolando
    B. Carrasco, L. Eaton, L. Letelier, C. Diaz, and R. Garcia-Gonzales. 2011. Heterogeneous genetic structure in a natural population of Rauli (Nothofagus nervosa). Cien. Inv. Agr. 38(3): 441-452. Heterozygote deficiencies in natural populations of outbreeding tree species are common and thought to be due mainly to biparental inbreeding. Inbreeding is believed to be caused by family structure within populations, a product of limited seed dispersal and probably limited pollen dispersal. Although both theory and simulation studies predict that structure should be apparent where trees are isolated by distance, most studies of structure in natural populations have detected only a weak spatial genetic structuring. In this contribution, we compare the use of spatial autocorrelation methodology and F statistics with the concept of relatedness to examine the spatial genetic structure in the natural population of a native southern beech and to explore the discrepancy between theory and observations. Autocorrelation detected structure in only a few of the nine enzyme loci tested in an estimated patch size of approximately 10 m. By successively eliminating the largest distances in the Gabriel map, the population was separated into groups or patches of neighbors, which were then tested for relatedness. Three groups of relatives were found interspersed with seven groups of unrelated individuals. The F statistics for these groups also showed weak genetic structure. We suggest that heterogeneity of family structure within natural populations may be one reason why more spatial genetic structure has not been detected.
  • No Thumbnail Available
    Item
    In vitro culture of Luma chequen from vegetative buds
    (2013) Mancilla, Hector; Quiroz, Karla; Arencibia, Ariel; Carrasco, Basilio; Garcia-Gonzales, Rolando
    Luma chequen, a small tree or large shrub belonging to the Myrtaceae family, is endemic to South America and has medicinal, nutritional and ornamental potential. However, its native habitat is deteriorating gradually, and it is suffering from the effects of fragmentation that is being caused by the conversion of forest land to agricultural land and the natural expansion of monocultural plantations of exotic species, such as Pinus radiata. The purpose of this work is to develop an effective procedure for establishing in vitro cultures of the native Chilean species L. chequen. Aseptic nodal segments were evaluated after exposure to a disinfecting agent (1% solution of sodium hypochlorite) for different lengths of time. Murashige and Skoog (MS) or Woody Plant (WPM) culture media with 6-Bencilaminopurine (BAP) or 2-isopentenil adenine (2-iP) added to a concentration of 1 mg L-1 were evaluated. Although no significant differences were observed between cultures with and without additives, 40.43% of the explant cultures were successfully established. Furthermore, the choice of basal medium or the addition of plant growth regulators was not found to affect the shoot formation efficiency.
  • No Thumbnail Available
    Item
    IN VITRO PROPAGATION OF CEDAR (Cedrela odorata L.) FROM JUVENILE SHOOTS
    (2011) Garcia-Gonzales, Rolando; Delgado, Miladys; Gonzalez, Yailin; Gonzalez, Anibal; Garriga, Miguel; Caligari, Peter D. S.; Carrasco, Basilio; Quiroz, Karla
    Cedrela odorata L. is one of the most important timber species currently traded in the Caribbean and Central America; however, it has been intensively exploited. In vitro techniques and clonal propagation can help to develop new plantations and assist in establishing improvement programs for this species. The aim of this study was to develop a protocol to establish in vitro conditions and to micropropagate this species from nodal explants from juvenile cuttings taken from field trees. Disinfection of node explants with 5% propiconazole CE 25 during 3 min resulted in 100% explant disinfection and 60% morphogenic response on those established explants. Shoot development was optimized by cultivating in vitro node explants in Murashige and Skoog basal medium supplemented with 2 mg L-1 6-bencilaminopurine and 3 mg L-1 naphthaleneacetic acid. This medium resulted in 100% shoot development from the in vitro node explants with a 3.93 cm mean height. Rooting was also stimulated 6 wk after individualization of the regenerated plants on the same micropropagation medium with a mean of 3.9 roots per plant. In vitro plants did not show morphologic differences when compared to ex vitro seeds.
  • No Thumbnail Available
    Item
    MOLECULAR TOOLS FOR RAPID AND ACCURATE DETECTION OF BLACK TRUFFLE (Tuber melanosporum Vitt.) IN INOCULATED NURSERY PLANTS AND COMMERCIAL PLANTATIONS IN CHILE
    (2011) Cordero, Cecilia; Caceres, Pablo; Gonzalez, Gloria; Quiroz, Karla; Bravo, Carmen; Ramirez, Ricardo; Caligari, Peter D. S.; Carrasco, Basilio; Garcia-Gonzales, Rolando
    Truffle (Tuber melanosporum Vitt.) culture is an agroforestry sector in Chile of increasing interest due to the high prices that truffles fetch in the national market and the recent evidence that its commercial production is possible in Chilean climatic and soil conditions. In this study, the efficiency of three methods of DNA extraction from a mix of 5 g of soil and roots from both nursery and field plants of Quercus ilex L. mycorrhized with T. melanosporum were evaluated, and a simple and reproducible protocol was established. Detection of T. melanosporum was performed by the technique of cleaved amplified polymorphic sequence (CAPS) from amplicons generated with the primers ADL1 (5'-GTAACGATAAAGGCCATCTATAGG-3') and ADL3 (5'-CGTTTTTCCTGAACTCTTCATCAC-3'), where a restriction fragment of 160 bp specific for T. melanosporum was generated, which allows the discrimination of this species from the rest of the species belonging to the Tuber sp. genus. Direct detection of T. melanosporum in one step was also obtained by polymerase chain reaction (PCR) from total DNA isolated from mycorrhized roots and with the primers ITSML (5'-TGGCCATGTGTCAGATTTAGTA-3') and ITSLNG (5'-TGATATGCTTAAGTTCAGCGGG-3'), generating a single amplicon of 440 bp. The molecular detection of T. melanosporum by the methods presented here will allow the rapid and accurate detection of mycorrhization of trees, both under nursery and field conditions. This technology will also provide more security to farmers by controlling the quality of the mycorrhized trees they will plant and also by following the mycorrhization status of established orchards.