Pachytene Analysis and Observations of Chromosome Association in Haploid Rice

Publisher Website
Google Scholar
Abstract
A pachytene analysis was made of the karyotype of haploid plants of cultivated rice (Oryza sativa). At diakinesis and metaphase-I, 30 different association types were found. The maximum association of haploid chromosomes is regarded as 2(3) + 3(2), but such types as 3(3) and 1(4) were also found with high frequency. Therefore, 2(3)+3(2) cannot be the maximum association. At pachytene, chromosome I showed associations with 3 different chromosomes. This chromosome could simultaneously associate with 3 others forming a group of 4. The distribution of association types may be considered to be a function of relative affinity and relative position. Assuming that the association in a haploid cell indicates the presence of homologous chromosome segments, the situation disproves the hypothesis that the basic number of rice could be 5.