The effect of medium composition on callus induction and plant regeneration frequencies from mature embryos of wheat cultivars with various resistance to Parastagonospora nodorum

Abstract

Bread wheat (Triticum aestivum L.) is one of the three most important cereal crops of the world and it is grown under a variety of pedo-climatic conditions. The crop suffers from many fungal pathogens, and especially from Parastagonospora nodorum (Berk.) Quaedvlieg, Verkley and Crous., which represents the major deleterious biotic stress factor to the cereal species in question. Parastagonospora (syn. Stagonospora, Septoria) nodorum blotch (SNB) is a disease of wheat (T. aestivum L.) elicited by this necrotrophic fungus on all green plant parts. It reduces assimilative area of glumes, peduncles, stems, leaf blades and sheaths what affects adversely quantity and quality of grain yield. Among wheat cultivars complete resistance to P. nodorum is not encountered. The effect of resistance breeding by conventional methods may be supported by biotechnological tools, e.g. by somatic embryogenesis or androgenesis. This study was undertaken to improve callus induction and plant regeneration from mature embryos of five winter wheat cultivars with various resistance levels to P. nodorum. For the purpose three type of auxins [2,4 dichlorophenoxyacetic acid (2,4-D); 3,6-dichloro-o-anisic acid (dicamba); 1-naphthaleneacetic acid (NAA)], and the effect of maltose vs. sucrose were evaluated. The results demonstrated relatively high embryogenic potential of all winter wheat cultivars used in the study. Inducing media supplemented with dicamba and sucrose were the most suitable for embryogenic callus formation, however, the highest efficiency of plant regeneration was obtained on medium without phytohormones.