THE RYE GENOME IN WINTER HEXAPLOID TRITICALES

Abstract

In 8 winter triticales (.times. Triticosecale Wittmack) chosen from the Cambridge crossing program, all 7 rye (Secale cereale L.) chromosomes were present. However, a number of rye cromosomes showed an obvious reduction in the size of C.sbd.bands at one or more telomeres, compared with normal rye. In 2 lines the C.sbd.band at the short arm telomere of 2R was obviously larger than normal in rye. Comparison of these results with those published for spring triticales suggests that divergent selection pressures may determine the number and structure of rye chromosomes in winter and spring lines. The differences may represent environmental adaptation and reflect selection pressure on the rye genome in triticale to conform to the cline for DNA amount per diploid genome on latitude previously described in cereal grain crops.