Development of new wheat varieties resistant to FHB through microspore in vitro selection technology

Germplasm resistant to Fusarium Head Blight (FHB) is the most important and powerful tool to manage the disease. Based on natural selection, microspore culture offers a method to develop new germ lines with a varying degree of resistance to FHB. An in vitro selection in presence of Fusarium trichothecenes was used to develop homozygous doubled haploid lines of various genotypes showing resistance against FHB. Microspores from F1 of 21 crosses of spring and winter wheat (Triticum aestivum L.) were subjected to selection against mixtures of Fusarium toxins (DON, 3-ADON, 15-ADON, NIV, T-2) in culture media. So far a total of 3232 doubled haploid lines were produced that have been incorporated into Canadian wheat breeding towards development of FHB resistant germplasm. The presence of trichothecenes in media had deleterious effects on the viability of microspores, formation of embryo like structures and regeneration rate of plants from embryo like structures. The response of different crosses was different to mycotoxins and as well as to media components and growth regulators. We found a novel epigenetic modifier Trichostatin A to be very efficient in stimulating embryogenesis and improving regeneration of plantlets. We were able to regenerate doubled haploids for crosses very recalcitrant to tissue culture. The doubled haploids lines produced through microspore culture technique will be screened for FHB resistance and DON accumulation in growth chamber followed by field trials in different regions of Canada.