ABSTRACT
El objetivo fundamental de este trabajo fue describir los cambios morfoanatómicos y/o de elementos químicos que ocurren en explantes foliares de Coffea arabica L. cv. Catuai, inducidos a producir embriones somáticos. Los explantes se cultivaron en el medio de Murashige y Skoog con algunos suplementos. Se tomaron y fijaron muestras de los explantes en FAA o glutaraldehido con el fin de realizar estudios bajo microscopía óptica, epifluorescencia y electrónica (barrido y transmisión). También, se hizo un microanálisis de rayos X. Se logró embriogénesis somática directa e indirecta. Se describe el origen y se caracterizan morfoanatómicamente los embriones producidos. Entre los indicadores de inducción embriogénica pueden considerarse: deposición de calosa y cutina en las paredes celulares, deposición de almidón, presencia de material fibrilar o membranoso sobre callos embriogénicos. En relación a elementos químicos indicadores de embriogénesis en el cultivar de café estudiado, el calcio pareció jugar un papel importante, al igual que los iones cloro y sodio.
The objective of this research was to describe cultivated in Murashige and Skoogs culture medium. Samples of theexplants were placed in FAA or glutaraldehyde buffer with to be studied under optical, epifluorescence and electronic microscope (SEM and TEM). Aditionally X-rays microanalysis were made. Direct and indirect somatic embryogenesis was obtained. The origin of produced embryos was described and characterized from the morphoanatomical point of view. Among the markers of embryogenic induction can be regarded the following aspects: callose deposition and cutine on the wall cell, starch deposition and the presence of either fibrillar or membranous material on embryogenic calluses. Calcium seems to play an important role during embryogenesis as a chemical marker just as chlorine and sodium ions.
Subject(s)
Coffee/genetics , Coffea Cruda/analysis , Embryonic Development , Glutaral/analysis , Culture Techniques/classification , Agriculture , BotanyABSTRACT
Inter-simple sequence repeat (ISSR) markers were used to evaluate genetic divergence among eight Coffea species and to identify the parentage of six interspecific hybrids. A total of 14 primers which contained different simple sequence repeats (SSR) were used as single primers or combined in pairs and tested for PCR amplifications. Two hundred and thirty highly reproducible fragments were amplified, which were then used to estimate the genetic similarity and to cluster the Coffea species and hybrids. High levels of interspecific genetic variation were revealed. The dinucleotide motif (GA)9T combined with other di- tri- and tetra-nucleotides produced a greater number of DNA fragments, mostly polymorphics, suggesting a high frequency of the poly GA microsatellite motifs in the Coffea genomes. The genetic similarity ranged from 0.25 between C. racemosa and C. liberica var. dewevrei to 0.86 between C. arabica var. arabica and Hybrid N. 2. The C. arabica species shared most of its markers with five of the six hybrids suggesting that it is the most likely candidate as one of the progenitors of those hybrids. These results revealed that ISSR markers could be efficiently used for genetic differentiation of the Coffea species and to identify the parentage of Coffea interspecific hybrids
Subject(s)
Coffee/genetics , Genetic Markers , Random Amplified Polymorphic DNA TechniqueABSTRACT
The RAPD technique associated with restriction digestion of genomic DNA was used to assess the genetic variability within and among nine populations of Coffea arabica, including six progenies belonging to the Sarchimor germplasm, the progeny PR 77054-40-10 (Catuaí Vermelho IAC 81 x Icatu), and two commercial cultivars (IAPAR 59 and Catuaí Vermelho IAC-81). These populations were evaluated using analysis of molecular variance (AMOVA), genetic similarity among progenies, and percentage of polymorphic loci. A total of 99 RAPD markers were evaluated of which 67 (67.67 percent) were polymorphic. AMOVA showed that 38.5 percent and 61.5 percent of the genetic variation was distributed among and within populations, respectively. The fixation index (F ST) of the genotypes was 0.385. The mean genetic variability estimated within populations ranged from 15.58 (IAPAR 59) to 8.27 (Catuaí Vermelho IAC 81). A distinct level of genetic variability was revealed for each of the coffee progenies and varieties studied. The methodology used in this investigation was useful to determine the genetic variability within and among C. arabica L. populations providing significant information for coffee breeding