MORPHOLOGY AND CYTOLOGICAL BEHAVIOR OF ANEUPLOIDS OFSORGHUM BICOLOR

Abstract

Ten types of single trisomics were tentatively classified within a progeny of a selfed homozygous triploid plant of Sorghum bicolor Moench using morphological characteristics. Of the 111 offspring obtained, 40 were found to be diploid, 58 trisomic, 11 double trisomic, 1 triple trisomic and 1 plant (because no heads were formed) unknown. Most of these trisomics were less vigorous than the diploids. Trisomics differed in number of tillers, plant height, panicle length, and fertility. Two types of trisomics had abnormalities apparently related to the sterility observed in these types. In Type 8, pollen grains had papilliform appendages and in Type 9 ovaries contained tumorous growths.One double trisomic was tentatively identified as Type 1–4 according to morphological appearances. Cytological analysis of pairing relationships of metaphase I of this plant indicated a close correspondance to the theoretical expectation.The trisomic types (excluding variants) arranged in order of decreasing frequency of occurrence correlated well with their order in decreasing percentage of trivalent formation. This order, therefore, might be interpreted to give an indication of the relative length of the extra chromosome found in each trisomic type.