Protoplast fusion technology for somatic hybridisation in Phaseolus

Abstract

The success of interspecific breeding between Phaseolus vulgaris L. (PV) and the two donor species Phaseolus coccineus L. (PC) or Phaseolus polyanthus Greenm. (PP) requires the utilization of the donor species as female parents. Although incompatibility barriers are post-zygotic, success in such F1 crosses is very limited due to early hybrid embryo abortion. Rescue techniques for globular or early heart-shaped embryos have been improved but hybrid plant regeneration remains very difficult. In this study we describe the use of protoplast fusion techniques within the genus Phaseolus, as an alternative to succeed crosses between PP or PC and PV. Large numbers of heterokaryons have been produced using different genotypes and procedures for fusion, based either on electro-fusion (750 or 1500 V.cm-1), or on the use of a chemical micro-method with polyethylene glycol (PEG 6000) as the fusing agent. Both divisions of heterokaryons and the formation of heterokaryon-derived microcalli were observed.

Keywords

• Protoplaste
• fusion
• Phaseolus vulgaris
• Phaseolus polyanthus
• Phaseolus coccineus