Breeding and Genetics CYTOGENETICS OF SUGARCANE

The progress in the cytogenetics of sugarcane with special reference to researches during the last decade is reviewed. Standardisation of leaf squash, pollen grain squash and root t ip squash methods for chromosome study have been reported. Culturing of pollen grains and cells in vitro have been new additions. The basic chromosome number of Saccharum may be 5, 6, 8 and 10. A new line of investigation, i.e., study of chromosome morphology in several clones of Saccharum species, has been reported. The interspecific and intergeneric hybrids and nature of their chromosome constitution have been investigated. The Saccharum X Zea hybrid has been shown to be a genuine one. Recent data on the nature of pollen sterility in S. officinarum clones has shown that it may be genic. Critical meiotic studies have shown perfect pachytene pairing i n Narenga X Sclerostachya hybrids and colchicine induced polyploids of S. spontaneum. A recent view of Bremer tends to support Parthasarathy's hypothesis that S. barberi developed as a result of hybridisation between S. spontaneum and S. officinarum.