Cyto genetic studies of the b chromosomes in sorghum nitidum
Proceedings of the National Science Council Republic of China 4(3): 297-306
Of 249 progeny plants obtained from self cross of an S. nitidum plant with 1 B chromosome, 169 did not have B chromosome. Progeny plants (78) carried 1 B chromosome and only one each had 2 B and 3 B chromosomes. The mode of inheritance of B chromosomes is toward a decrease of B chromosome frequency in the offspring. In somatic cells of the anther wall, the B chromosomes did not seem to divide at anaphase and they sometimes lagged. Examination of microsporocytes showed that the 2-B chromosome type behaved in a more stable and regular fashion at meiosis than did odd number types. Meiotic elimination of the B chromosome was low in the 2-B plant. The lagging of a few B chromosomes suggest the presence of moderately defective but functioning centromere. The mean chiasma frequencies of the A chromosomes in the 0-B plants and the 1-B plants were compared by using t test; the latter was significantly higher than the former. However, no significant difference was shown in pollen fertility, plant weight, sessile spikelet number, tiller number and leaf size between 0-B class and 1-B types.