Sugarcane (S. Officinarum x S. Spontaneum)

Abstract

Sugarcane has been cultivated for thousands of years for producing sugar. Sugarcane is a fast-growing grass species that accumulates high amounts of sucrose in its stalks. Sugarcane is a complex polyploid with high levels of autopolyploidy and aneuploidy. Sugarcane belongs to the Saccharum species which include S. officinarum, S. spontaneum, S. robustum, S. barberi and S. sinense, species that have been used in the development of modern cultivars. S. spontaneum is known to possess wide genetic diversity and adaptability and has been used widely in modern introgression breeding. At time of crossing, biparental, melting pot and male-only mating are adopted. Melting pot involves crossing several males to one female, while male only involves intercrossing several plants. Several approaches to increase efficiency of breeding sugarcane have been adopted over the years. The proven cross and proven parents were popular in early days of sugarcane breeding. These have been superseded by family evaluation and estimation of breeding values using family data. Variety development involves testing genotypes across several field trials. However, sugarcane, unlike other crops, only experiences genetic recombination at crossing, and all subsequent stages are propagated from vegetative material. This disadvantage requires careful choice of parents to optimise the genetic recombinations required. The future of sugarcane breeding will focus on increasing genetic gains via family and parent evaluation, introgression to diversity gene pools and incorporating new genetic material as well as use of molecular markers to increase precision of trait breeding.