RELATIONSHIP BETWEEN CHROMOSOME-9 OF MAIZE AND WHEAT HOMEOLOGOUS GROUP-7 CHROMOSOMES

Comparison of the genetic map of maize chromosome 9 with maps of wheat chromosomes has revealed a high degree of colinearity between maize c hromosome 9 and the group 4 and 7 chromosomes of wheat. The order of D NA markers on the short arm and a proximal region of the long arm of t he genetic map of maize chromosome 9 is highly conserved with the mark er order on the short arm and proximal region of the long arm of the g enetic maps of the wheat homeologous group 7 chromosomes. A major part of the long arm of the genetic map of maize chromosome 9 is homeologo us with a short segment in the proximal region of the long arm of the genetic map of the wheat group 4 chromosomes. Evidence is also present ed that maize chromosome 9 has diverged from the wheat group 7 chromos omes by both a pericentric and a paracentric inversion. The paracentri c inversion is probably unique to maize among the major cereal genomes .