Study of the somaclonal variation produced by different methods of polyploidization in Asparagus officinalis L.

Abstract

Polyploid plants have been induced in differentAsparagus officinalis L. breeding programs in order to obtain plants with improved agronomical traits, such as large spear diameter or segregation ratios with a higher number of males. The polyploidization methods can produce somaclonal variation in the polyploid plants obtained and, therefore, unwanted changes in the agronomical traits of the initial elite plants. We used two different polyploidization methods to induce polyploid plants from diploid genotypes of commercial varieties and tetraploid genotypes of the Spanish landrace ''Morado de Hue ´tor''. The first method was the culture of rhizome buds in the medium ARBM-3 (Asparagus Rhizome Bud Medium), supplemented with different concentrations of colchicine (0.1-0.75 g l -1 ) for 10 and 20 days. The best polyploidization rate obtained was 25 % (0.5 g l -1 colchicine for 10 days). The second method was the regeneration of polyploid plants from callus culture, resulting in a polyploidization rate of 40 and 12.5 % for the diploid genotype CM077 and the tetraploid genotype HT156, respectively. Additionally, we have developed a new protocol to separate the mixoploids generated into their different genetic components, obtaining plants with a unique ploidy level. EST-SSRs markers were employed to analyze the genetic stability of polyploidy plants. Somaclonal variation was not detected for polyploidy plants obtained through the culture of rhizome bud explants. Therefore, these polyploid plants should maintain the agronomical traits of the initial elite plants. However, somaclonal variation was detected in the polyploid plants regenerated from callus culture.

Production of “super-males” of asparagus by anther culture and its detection with SSR-ESTs

“…Furthermore, different ploidy levels in the plantlets regenerated from the same anther were detected. The regeneration of tetraploid and octoploid plantlets from diploid microspores, as well as the mix of ploidy levels, can be possible due to the high endoreduplication rate occurring in the callus culture in A. officinalis (Kunitake et al 1998;Raimondi et al 2001;Pontaroli and Camadro 2005;Regalado et al 2015b), also described in the anther culture of A. officinalis Wolyn and Feng 1993;Shiga et al 2009). Other important result obtained in this ploidy analysis is the increase of the spear diameter of the plantlets associated with ploidy level (Fig.…”

“…A maximun of 16 plantlets regenerated from callus developed from a single anther were analyzed. The parts with different ploidy level of the plantlets cataloged as mixoploid were separated following the protocol described by Regalado et al (2015b). Growth regulators (mg l -1 ) Casein (mg l -1 ) Glutamine (mg l -1 ) Sucrose (g l -1 ) Glucose (g l -1 ) Agar (g l -1 ) NAA 2,4-D BA (Murashige and Skoog 1962) and adjusted to pH 5.7 Table 2 Composition of auxin and cytokinins of proliferation media (PM)…”

“…These ESTSSRs were chose because they amplified at least three alleles in plants of tetraploid genotype HT156 (Regalado et al 2015b), source of the anthers used as explants in this work. The same plantlets characterized with the sex-linked marker Asp1-T7 were characterized with these EST-SSRs.…”

Conservación de plantas regeneradas in vitro y análisis de la variación somaclonal de Cinchona officinalis, Linneo

“…Por ende, al igual que la propagación, es de importancia mantener la integridad genética derivada de las plantas propagadas bajo estas condiciones. La variación somaclonal puede originarse bajo ciertas situaciones de estrés que se producen durante el cultivo in vitro, los factores que la originan son diversos y han sido estudiados en algunas especies (Tabla 1) (Sharma et al, 2007Chandrika et al, 2010Rathore et al, 2011;Regalado et al, 2015).…”

“…Al igual que en Aloe vera (Rathore et al, 2011) y Bletilla striada produce cambios en el genotipo (Chakrabarty et al, 2003;Regalado et al, 2015). A parte de la presencia de esta auxina, el factor que también influyó para la variabilidad fue el tipo de regeneración, a través de callo (Fig.…”