Multiplicación, histodiferenciación y regeneración de suspensiones celulares embriogénicas en plátanos vianda “Navolean” (AAB)

The results obtained show that the best cell density for the multiplication of the cell suspensions in the cultivar ‘Navolean’ is 3.0% settled cell volume. In the histo-differentiation phase the greatest formation of somatic embryos in the globular stage was obtained using a density of 12.0% final cell volume in liquid culture medium. The maturation of the embryos and an increase in germination was possible on using 0.5 gFW of somatic embryos during 30 days in the maturation culture medium. Using temporary immersion systems with 0.5 gFW of mature somatic embryos, the germination value was increased to 77.40%Key words: Musa, settled cell volume (SCV), somatic embryogenesis, temporary immersionEl mejor resultado para la multiplicación de las suspensiones celulares embriogénicas en el cv. ‘Navolean’ se obtuvo al utilizar una densidad celular del 3.0% del Volumen de Células Sedimentadas. En la etapa de histodiferenciación se logró la mayor formación de embriones somáticos en etapa globular utilizando como densidad 12.0% de volumen final de células en medio de cultivo líquido. Al emplear 0.5 gMF de embriones somáticos durante 30 días de cultivo en el medio de cultivo de maduración, fue posible lograr la maduración de los embriones e incrementar la germinación. Empleando sistemas de inmersión temporal con 0.5 gMF de embriones somáticos maduros se incrementó el valor de germinación a 77.40%.Palabras clave: embriogénesis somática, inmersión temporal, Musa, volumen de células sedimentadas (VCS

Embriogénesis somática en el cv. Navolean a partir de ápices de brotes de yemas axilares

In order to develop embryogenic cultures in AAB Musa genotypes without persistent male inflorescence, the process has had greater success from proliferating meristems for callus formation with embryogenic structures. Based on the previous information, other alternative explant sources for somatic embryogenesis development in cv. Navolean. Meristematic apexes were cultured in p5 culture medium supplemented with thidiazuron and ancymidol (0.2, 0.4, 0.6, mg.l-1) to obtain axillary buds. Later, axillary buds and proliferated meristems were tested for callus induction with embryogenic structures combinations with different 2,4-D concentrations. The best growth regulator for obtaining axillary buds was ancymidol (0.2 mg.l-1). For callus formation with embryogenic structures, axillary buds at 1.0 mg.l-1 2,4-D provided a higher percentage (13.6%). These results permitted the development of embryogenic cell suspensions from somatic embryos.Key words: Ancymidol, embryogenic cell suspension, plantainEl desarrollo de cultivos embriogénicos en los genotipos AAB de Musa, que no poseen inflorescencia masculina persistente, ha tenido mayor éxito a partir de multiyemas para la formación de los callos con estructuras embriogénicas pero esto pudiera incrementar la variación somaclonal. Teniendo en cuenta lo anterior se trabajó en la determinación de otra fuente de explante inicial alternativa para el desarrollo de la embriogénesis somática en el cultivar objeto de estudio. Se cultivaron brotes axilares en el medio de cultivo P5 suplementado con tidiazuron y ancimidol (0.2; 0.4; 0.6 mg.l-1 cada uno por separado) para lograr la brotación de yemas axilares. Posteriormente para formar los callos con estructuras embriogénicas se colocaron los ápices de brotes obtenidos de yemas axilares en un medio de cultivo ZZ con diferentes concentraciones de 2,4-D. El mejor regulador del crecimiento para la brotación de yemas axilares fue el ancimidol (0.2 mg.l-1). Para la formación de callos con estructuras embriogénicas, la concentración de 1.0 mg.l-1 de 2,4-D propiciaron el mayor porcentaje (13.6%). A partir de los embriones somáticos producidos se logró el establecimiento de suspensiones celulares embriogénicas. Se demostró que es posible el desarrollo de la embriogénesis somática en el cv. Navolean no solo a partir de scalps de multiyemas.Palabras clave: ancimidol, plátanos, suspensiones celulares embriogénica

Somatic embryogenesis in cv. Navolean using shoots apexes from axillary buds

In order to develop embryogenic cultures in AAB Musa genotypes without persistent male inflorescence, the process has had greater success from proliferating meristems for callus formation with embryogenic structures. Based on the previous information, other alternative explant sources for somatic embryogenesis development in cv. Navolean. Meristematic apexes were cultured in p5 culture medium supplemented with thidiazuron and ancymidol (0.2, 0.4, 0.6, mg.l-1) to obtain axillary buds. Later, axillary buds and proliferated meristems were tested for callus induction with embryogenic structures combinations with different 2,4-D concentrations. The best growth regulator for obtaining axillary buds was ancymidol (0.2 mg.l-1). For callus formation with embryogenic structures, axillary buds at 1.0 mg.l-1 2,4-D provided a higher percentage (13.6%). These results permitted the development of embryogenic cell suspensions from somatic embryos. Key words: Ancymidol, embryogenic cell suspension, plantai

Multiplication, histodifferentiation and regeneration of embryogenic cell suspensión on the plantain cultivar ‘Navolean’ (AAB)

The results obtained show that the best cell density for the multiplication of the cell suspensions in the cultivar ‘Navolean’ is 3.0% settled cell volume. In the histo-differentiation phase the greatest formation of somatic embryos in the globular stage was obtained using a density of 12.0% final cell volume in liquid culture medium. The maturation of the embryos and an increase in germination was possible on using 0.5 gFW of somatic embryos during 30 days in the maturation culture medium. Using temporary immersion systems with 0.5 gFW of mature somatic embryos, the germination value was increased to 77.40% Key words: Musa, settled cell volume (SCV), somatic embryogenesis, temporary immersio

Molecular diversity of Cuban cassava (Manihot esculenta Crantz) cultivars assessed by simple sequences repeats (SSR)

A total of 36 microsatellites (SSR) markers were used to analyze the genetic diversity of 163 accessions of cultivated cassava (Manihot esculenta Crantz), 94 accessions of them from the Cuban Cassava Germplasm Collection and 69 genotypes from different countries and conserved at the International Center for Tropical Agriculture (Colombia). This study was carried out to determine genetic diversity within and between all accessions to promote their better use and conservation strategies. Thirty-four of those markers were used for the genetic diversity study based on their higher polymorphism. The Cuban cultivars showed the highest average allele number per loci with 5.8 and 100% of the loci were polymorphic, as well as those from Guatemala. The average proportion of individual heterozygocity observed (HO) was high (0.5918 ± 0.0351), while the highest HO rates were observed in groups of genotypes from Cuba (0.6016) and Tanzania (0.6459). The total heterozygocity (HT) was high (0.6538 ± 0.1770), but only 7.4% (GST = 0.0740 ± 0.0377) was due to differences between the five countries studied. Genetic differentiation coefficients (estimated by F-statistics) were low to moderate (FST > 0.04) and 17 unique alleles with low frequency were found in Cuban cultivars. The results provide the first molecular characterization of Cuban cassava genotypes and showed a wide diversity among landraces from Cuba. Application of this valuable information can be used for genetic diversity conservation and genotype identification studies for the genetic breeding program of cassava

Field evaluation of regenerated plants by somatic embryogenesis from shoots apexes of axillary buds in ´Navolean’ (Musa spp., AAB).

The use of shoots apexes from axilary buds for callus induction with embryogenic structures in plantain ‘Navolean’ (Group AAB) permitted to develop a plant regeneration method through out somatic embryogenesis. In order to know the phenotypic variants that may be produced with the previously mentioned method , 1000 plants were planted in field conditions in comparison to those coming from somatic embryos obtained from multibuds as initial explants and organogenesis-derived plants (shoot tips)and conventionally derived plants (corms), during two growing cycles. The main morphological characters and yield components were evaluated. The total frequency of somaclonal variation during the first growing cycle in plants coming from somatic embryos obtained from shoots apexes from axilary buds as initial explants were 1.1%, and 8,6% in regenerated plants from somatic embryos obtained from multi-buds as initial explants. Later, in this same growing cycle, plants regenerated from somatic embryos (both sources) showed a similar performance between them and they were significantly superior in all evaluated variants in comparison to corm-derived plants. In the second growing cycle, significant differences were not observed in yield components of suckers from evaluated plants, in spite of the propagation method used. With regard to somaclonal variation, the best performance was obtained with shoots apexes from axilary buds as explants. Finally, the feasibility of using the new method was shown. Key words: embryogenic cell suspensions, somaclonal variatio