Cytological studied in Saccharum. IV. Hybrids from S. officinarum x S. spontaneum
Jour Heredity 48(4): 141-145
Meiotic chromosome pairing is described for hybrids from 80-chromosome Saccharum officinarum. clone Cana Blanca x 96-chromosome S. spontaneum. clone Mandalay. The maximum association of chromosomes observed in 128-chromosome (2n + n) hybrids is 63II + 2I. In an 88-chromosome (n + n) hybrid, 44II is the maximum chromosome association. There is no evidence of synaptic association between the chromosomes of S. officinarum and those of S. spontaneum in either 2n + n or n + n hybrids. Autosyndesis in the hybrids indicates that the 40 gametic chromosomes of S. officinarum consist of 2 groups of 20, and, similarly, that the 48 gametic chromosomes of Mandalay, S. spontaneum, consist of two 24-chromosome groups. The proposal that 10 is the basic chromosome number in S. officinarum is supported. Either 8 or 12 as basic chromosome numbers in the Mandalay clone of S. spontaneum would fit the data presented. Eight seems preferable, however.