Chiasma frequency was determined from total chiasma counts, and the distribution of these exchanges was determined by the ratio of proximal to distal chiasmata. No effect of trisomy IO could be demonstrated. Confirmation was obtained of earlier work showing more proximal and fewer distal chiasmata in K10 plants than in controls. However, diakinesis data failed to confirm the ability of KIO to i...

The recombination frequency as influenced by five independent recessive ds genes was measured on three segments of different chromosomes of rice, Oryza sativa L. Each ds gene in the homozygous condition resulted in an almost equally reduced recombination frequency in the three segments. When the mean reduction in recombination frequency was related to the reduction of chiasma frequency, the fiv...

N an individual heterozygous for an interchange between two non-homoloI gous chromosomes, the observed amount of gene recombination in an interstitial region depends on the frequency of the respective centromere disjunction types and upon the chiasma (crossover) frequency expected for the two interstitial regions of the interchange complex. An interstitial region is considered to be the chromos...