THE EXISTENCE OF A DUPLICATED OR PARALLEL GENETIC SYSTEM FOR FERTILITY RESTORATION IN CMSC OF MAIZE (ZEA-MAYS L.)

The inheritance of fertility restoration in cmsC in maize proved to be very complex. Besides the group of three dominant complementary genes (Rf4, Rf5. Rf6), the data hitherto collected indicated that this syst em of fertility restoration in cmsC was not unique. Using the group of inbred lines in C-cytoplasm, converted to full restorers, as female t esters for the group of inbreds known as restorers for cmsC, we found cases of segregation in F2 generations in ratio of 15:1 male fertile t o male sterile plants respectively. At the same time, the male sterile segregants did not appear in any of the two backcrosses, what was act ually the crucial criterion for ''absolute restorerness'' of the cross ed parents. This situation is possible only if fertility restoration o f the mio parents used in crosses was based on different genetic syste ms. This second one, here discovered, could be a duplication, partial or complete, of the previously described one, or a parallel and indepe ndent genetic device for fertility restoration in cmsC.