The Cytological Mechanism of Male Sterility in Intergeneric Hybrids of Sorghum×Saccharum
2014 年 79 巻 1 号 p. 79-83
詳細
2014 年 79 巻 1 号 p. 79-83
Microsporogenesis was analyzed in a rare intergeneric hybrid of sugarcane produced from a Sorghum×Saccharum cross. The original hybrid was found to be non-flowering. Some of the somaclones of this hybrid obtained by irradiating the callus at four Kr showed flowering. However, the somaclones were found to be male sterile. Here we report the occurrence of syncyte formation and subsequent chromatin degeneration in the somaclones of this hybrid. Syncytes were recorded in 58.3–85.7% pollen mother cells of somaclones that flowered. Meiosis progressed normally in microsporocytes till leptotene where the uninucleate cells appeared normal with loosely tangled, long thread-like chromosomes. Later, the whole nuclear mass divided into two or more groups, forming syncytes with multiple nuclei and micronuclei. Cytokinesis fractionated the syncyte into abnormal meiotic products. Degeneration of chromatin content was observed in both syncytes as well as in the uninucleate cells, resulting in anther sacs with fragmented chromatin mass. Complete pollen sterility resulted from these abnormalities. However, these plants were found to be female fertile and hybrids could be obtained by using it as a female parent in crosses with sugarcane.
