Cytogenetical analysis on aneuploids obtained from pollenclones of rice (Oryza sativa L.).

Rice aneuploids were obtained from 1,715 pollenclones with a mean frequency of 10.2% in anther culture (1983 to 1985). Among the aneuploids obtained, the frequency of primary trisomics ranged from 5.4% to 6,7%, tetrasomics from 1.1% to 1.7% monosomics from 0.9% to 1.3%, nullisomics from 0.5% to 1% and double trisomics from 0.5% to 0.7%. The chromosome complements of those aneuploids were identified by pachytene analysis on the absolute length of the extra chromosomes. Pollen clonal aneuploids showed a different range of variation in agronomic characters from dihaploids of the same origin but the phenotypic variations ressembled those found in aneuploids created by conventional breeding methods. The meiotic chromosome behavior of PMC revealed various chromosomal aberrations of aneuploids: loose pairing, trivalents, univalents, straggling chromosomes, bridges and laggards.