The effect of specific chromosome and cytoplasm substitutions on the tissue culture response of wheat (Triticum aestivum) callus.

Calli were initiated from immature embryos of four lines of hexaploid wheat (Triticum aestivum L. em. Thell), the euplasmic nuclear donor 'Chinese Spring', 'Chinese Spring' in which both 4B chromosomes were substituted by those of the variety 'Cappelle-Desprez' and two alloplasmic lines in which these nuclei were substituted into the cytoplasm of Aegilops ovata. The calli were found to differ in their initia growth rates and their ability to organise shoot primordia and regenerate shoots. The 'Cappelle' 4B chromosomes had a very significant effect on all these characters. The potential for modelling genotypes for improved tissue culture characteristics is discussed.