Improved efficiency of doubled haploid generation in hexaploid triticale by in vitro chromosome doubling

Abstract

Background: Doubled haploid production is a key technology in triticale research and breeding. A critical component of this method depends on chromosome doubling, which is traditionally achieved by in vivo treatment of seedlings with colchicine.

Results: In this study we investigated the applicability of an in vitro approach for chromosome doubling based on microspore culture. Our results show a pronounced increase in the proportion of doubled haploid triticale plants compared to the spontaneous doubling rate, but also compared to the doubling obtained by the standard in vivo approach. In addition, the frequency of plants surviving from culture medium to maturity is also much higher for the in vitro approach. Colchicine concentrations of 1 mM for 24 h or 0.3 mM applied for 48 or 72 h during the first hours of microspore culture performed best.

Conclusions: Our results suggest that for triticale, in vitro chromosome doubling is a promising alternative to the in vivo approach.

Figure 1

Effect of colchicine on embryo formation. Effect of different colchicine concentrations applied for 72 h on embryo formation 4 weeks after microspore isolation.

Figure 2

In vitrochromosome doubling.(A) Heatplot for the rate of fertile doubled haploid plants among regenerated green plants obtained by the tested in vitro methods and by the conventional in vivo approach. (B) Mosaic plot visualizing the contingency table. The area of each tile is proportional to the corresponding cell entry and the colors reflect the residuals (fit or lack of fit) of the loglinear model.