LOCATION OF A GENE REGULATING COLD-INDUCED CARBOHYDRATE PRODUCTION ONCHROMOSOME 5A OF WHEAT

Major changes in osmotic potential during cold acclimation are due to changes in sugar concentration, and there is a good correlation betwee n sugar content and frost tolerance. The objective of the present stud y was to localize a gene(s) responsible for carbohydrate accumulation during cold acclimation on chromosome 5A of wheat using recombinant li nes developed from the cross between the substitution lines Chinese Sp ring (Cheyenne 5A) and CS(Triticum spelta 5A). Previously, major genes influencing frost resistance (Fr1) and vernalization requirement (Vrn 1) had been localized on the long arm of that chromosome. The T. spelt a 5A chromosome carrying the Fr1 (frost-sensitive) allele for frost to lerance and the Vrn1 (spring-habit) allele for vernalization requireme nt did not have a major effect on the sucrose and fructan contents in the Chinese Spring background. On the other hand, the presence of Chey enne alleles for vernalization requirement, vrn1, and frost tolerance, fr I, significantly increased sugar concentrations. A recombinant lin e thought to exhibit recombination between the Vrn1 and Fr1 loci sugge sted that the gene regulating sucrose accumulation was closely associa ted with, or else represented a pleiotropic effect of, Vrn1, but was s eparable from the Fr1 locus.