RFLP MAPPING OF RYE CHROMOSOME 7R REVEALS A HIGHLY TRANSLOCATED CHROMOSOME RELATIVE TO WHEAT

A RFLP map of rye, Secale cereale, chromosome 7R was constructed using 22 DNA probes including genes coding for leaf acyl carrier protein III, chloroplast fructose-1,6-bisphosphatase, alpha-amylase-2, EmBP-1, and a peroxidase. All probes had previously been located in wheat, Triticum aestivum, and a comparison of the wheat and rye maps reveals that chromosome 7R contains four segments that are homologous with segments of chromosomes of four homoeologous groups of wheat, 5L, 4L, 7S and 7L including the centromere, and 2S. Within these segments the rye and wheat maps are colinear and orientated in the same way relative to the centromere. The implications of rearrangements such as detected in 7R for triticale breeding and interspecific chromosome recombination and manipulation are discussed.