Manejo de la contaminación bacteriana en la propagación in vitro de yemas axilares de Colocasia esculenta cv. ‘INIVIT MC-2012’

The in vitro propagation of Colocasia esculenta is limited by the presence of microbial contaminants, especially bacteria. The objective of this work was to demonstrate that the inclusion of actions for the bacterial contamination management in the in vitro propagation of C. esculenta cv. ‘INIVIT MC-2012’, from field explants, can reduce losses. Two in vitro propagation protocols were used and the incidence of bacterial contaminants in the establishment and multiplication stages was compared. One protocol modified the other with actions for the management of bacterial contamination. In each one, 20 primary rhizomes were taken from which at least two axillary buds were extracted and from each one a line was established. The number of explants contaminated with bacteria per subculture was quantified. Bacterial contamination was observed in the culture medium below or around the explants, indicating the initial explant as the primary source of contamination. With the application of the modified protocol, the percentage of losses due to bacterial contamination in all subcultures evaluated was reduced. In the in vitro establishment it did not exceed 5%. The combination of actions for the management of bacterial contamination among which are the reduction of the size of the explant, the work by lines and the visual detection of contaminants prior to the subculture of the plant material reduces the presence of bacterial contaminants in the in vitro propagation of C. esculenta cv. ‘INIVIT MC-2012’. Keywords: contaminant detection, explant, taroLa propagación in vitro de Colocasia esculenta se limita por la presencia de contaminantes microbianos, especialmente bacterias. El objetivo de este trabajo fue demostrar que la inclusión de acciones para el manejo de la contaminación bacteriana en la propagación in vitro de C. esculenta cv. ‘INIVIT MC-2012’ a partir de explantes de campo, puede reducir las pérdidas. Se emplearon dos protocolos de propagación in vitro y se comparó la incidencia de contaminantes bacterianos en las fases de establecimiento y multiplicación. Un protocolo modificó al otro con acciones para el manejo de la contaminación bacteriana. En cada uno se partió de 20 rizomas primarios de los que se extrajeron al menos dos yemas axilares y de cada una se estableció una línea. Se cuantificó el número de explantes contaminados con bacterias por subcultivo. La contaminación bacteriana se observó en el medio de cultivo debajo de los explantes o alrededor de estos lo que indica al explante inicial como fuente primaria de contaminación. Con la aplicación del protocolo modificado se redujo el porcentaje de pérdidas por contaminación bacteriana en todos los subcultivos evaluados. En el establecimiento in vitro no rebasó el 5%. La combinación de acciones para el manejo de la contaminación bacteriana entre las que se encuentran la reducción del tamaño del explante, el trabajo por líneas y la detección visual de contaminantes previo al subcultivo del material vegetal reduce la presencia de contaminantes bacterianos en la propagación in vitro de C. esculenta cv. ‘INIVIT MC-2012’. Palabras clave: explante, detección contaminantes, malang

Evaluación en campo de plantas regeneradas por embriogénesis somática a partir de ápices de brotes de yemas axilares en cv. ‘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 variationEl uso de ápices de brotes de yemas axilares para la inducción de callos con estructuras embriogénicas en el cultivar de plátano vianda ‘Navolean’ (Grupo AAB), posibilitó el desarrollo de una metodología de regeneración de plantas por embriogénesis somática en el cultivar objeto de estudio. Con el objetivo de conocer la variabilidad fenotípica que se podría producir mediante la misma, se plantaron en el campo 1 000 plantas que se compararon durante dos ciclos de cultivo con otras procedentes de embriones somáticos obtenidos de scalps de multiyemas como explante inicial, con plantas obtenidas por organogénesis (ápices meristemáticos) y mediante la propagación convencional (cormos). Para ello se evaluaron los principales caracteres morfológicos de la planta y componentes del rendimiento.La frecuencia total de variación somaclonal durante el primer ciclo de cultivo en las plantas procedentes de embriones somáticos donde el explante inicial habían sido ápices de brotes de yemas axilares fue de 1.1% y de 8.6% en las plantas regeneradas de embriones somáticos scalps de multiyemas. Luego en este mismo ciclo de cultivo las plantas regeneradas de embriones somáticos (ambas procedencias) mostraron un comportamiento similar entre ellas y en todas las variables evaluadas fueron superiores en relación con las plantas procedentes de cormos con diferencias significativas. En el segundo ciclo de cultivo, al evaluar los hijos, de las plantas estudiadas no se observaron diferencias significativas en los componentes del rendimiento, independientemente del método de propagación utilizado. Referente a la variación somaclonal, se obtuvo el menor índice en las plantas obtenidas por embriogénesis a partir de ápices de yemas axilares. Finalmente se demostró la factibilidad de utilizar la nueva metodología desarrollada.Palabras clave: suspensiones celulares embriogénicas, variación somaclona

Obtaining of somatic embryo and establishment of embryogenic cell suspension in Plantain cv ‘Navolean’ (AAB)

Cells suspension of plantains and bananas with promising results have been reported internationally, however, in Cuba it is not at so for AAB group. So, the following working objectives have to be considered: in vitro multiplication of the material used as explant source. For in vitro multiplication of the material used as explant source. For in vitro multiplication of the material, several 6-BAP and IAA concentration were studied. Induction of embryogenic cultures was the developed form “scalps” incubated in solid medium ZZ. Suspensions were established in 10 ml and 25 ml Erlenmeyers containing liquid medium ZZ. The best medium for explant multiplication was MS (salts and vitamins), additional thiamin (1 mg.l-1), sucrose (40 g.l-1); 4.50 mg.l-1 6-BAP, 0.88mg.l-1 IAA and solidified agar (6.0 g.l-1) (medium 7). A 4.66% callus formation with embryogenic cultures was obtained, and cell suspensions were established 20 days after incubation in 10 ml Erlenmeyers. Media were changed every third day. Key Words: somatic embryogenesis, plantain, scalp

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

New somaclone of plantain (Musa AAB) obtainet by biotechnological techniques

Results obtained from Plant Breeding Programs on Musa spp. In the tissue culture Laboratory at INIVIT since 1987 is presented. Procedures described by IAEA with some modifications for mutation induction through in vitro culture were used. Meristematic sproutings (2-3 mm) from in vitro formed buds were isolated. Ionizan radiaton were carried out in a Cobalt 60 source at a rate of 50 Gy. A somaclone (‘Z-13’) is generalized due the following characteristics; tolerance to “Black Sigatoka” disease (Mycosphaerella fijiensis Morelet), average height of 2.70 m, a bunch in a truncated cone shape with 16.5 fingers per hand and a predominantly astringent taste, the stem is under soil level to have a better anchoar and a higher yield. Morphologic and molecular characterization showed the differences within selected variants in relation to the donor. The new mutant is proposed to be registered as a new cultivar by The International Atomic Energy Agency (IAEA). Advanced growers from Villa Clara and Ciego de Ávila, Cuba participated in the selection program. Key words: buds, in vitro mutations, tissue culture, somaclonal variatio