Oryzalin Treatment of Potato Diploids Yields Tetraploid and Chimeric Plants from which Euploids could be Derived by Callus Induction

Abstract

Shoot apices from six diploid potato genotypes for polyploidisation were treated with oryzalin and colchicine solutions at different concentrations and incubation times. In addition to chimeric plants, diploids, one octoploid and completely ploidy doubled plants (4x) were regenerated in these experiments. Tetraploid plants were obtained for three of the six genotypes treated with oryzalin, and no tetraploid plants were obtained after colchicine treatments of any of the genotypes. The best result of 43% tetraploid plants was achieved using 28.8 μM oryzalin and 24 h of incubation with the L37 genotype. Moreover, we determined that doubled plants should not be selected on the basis of a single measurement and require additional ploidy checks in successive clonal generations. Some L37 plants that were initially identified as tetraploids by flow cytometry produced diploid or mixoploid plants in the next clonal generation. Morphological characters of doubled L37 plants were compared with the original genotype. The PVY resistance present in a parental clone was maintained in all regenerants and significant differences among ploidy variants were found for some quantitative characters. Molecular AFLP analyses did not show any differences among genotypes. Since polyploidizing substances may produce a large proportion of chimeric plants, we applied a method to increase the number of tetraploid plants. Callus culture of chimeric leaf explants was performed on regeneration medium and tetraploid shoots were obtained in four of the six genotypes tested. The best result of 40% tetraploid plants was achieved with explants from the L37 genotype. This method was successful in producing additional tetraploid genotypes from mixoploid plants obtained after oryzalin treatments.

Genetic stability at nuclear and plastid DNA level in regenerated plants of Solanum species and hybrids

“…Binsfield et al (1996), for example, found isozyme variation in plants regenerated from S. tuberosum. By contrast, Barandalla et al (2006) did not detected AFLP polymorphism in regenerated plants of diploid Solanum genotypes. To shed additional information on the association between molecular stability and somaclonal variation, in this work we produced regenerants from 29, 39, 49 and 69 genotypes of Solanum species and hybrids using a regeneration method routinely employed in our laboratory (Iovene et al 2002).…”

“…Lack of polymorphisms associated with in vitro regeneration was reported in tomato (Smulders et al 1995), Norway spruce (Fourré et al 1997), oil palm (Rival et al 1998), begonia (Bouman and De Klerk 2001), almond (Martins et al 2004), and potato (Barandalla et al 2006;Sharma et al 2007) using RAPD, ISSR and AFLP markers. By contrast, major differences were found in alfalfa (Piccioni et al 1997), in Codonopsis lanceolata (Guo et al 2006), wild pear (Palombi et al 2007) using RAPD and ISSR markers.…”

Impact of colchicine application during callus induction and shoot regeneration on micropropagation and polyploidisation rates in two Miscanthus species

“…The autotetraploids of Rosa chinensis minima exhibited lower pollen stainability in comparison with diploids (Zlesak et al 2005). However, chromosome doubling in potato plants did not affect pollen viability (Barandalla et al 2006).…”

Colchicine and oryzalin effects on tetraploid induction and leaf anatomy of Solanum commersonii ssp.

“…The choice of the antimitotic substance and adjustments in its concentration and exposure time are limiting factors in polyploidization induction. Some studies have reported that there is evidence of a strong interaction between the antimitotic treatment and potato genotype (BARANDALLA et al, 2007;CHAUVIN et al, 2003).…”

“…With regard to obtaining tetraploid plants in potato genotypes, the use of oryzalin was more effective than colchicine. However, the success obtained with the use of oryzalin depends on the genotype (BARANDALLA et al, 2007;CHAUVIN et al, 2003). The use of oryzalin (10µM; exposure: 24h) provided the best chromosome duplication results only for the L 37 potato genotype (CHAUVIN et al, 2003).…”