On average the MSIRI has released one new cane variety every year over the last 50 years. Sugar yield has significantly increased at a rate of 0.5% per unit area per year during that period. This increase is largely due to the use of improved varieties.
The variety-improvement programme lays emphasis on high yielding and high-sucrose varieties resistant to the main diseases, adapted to various agro-climatic conditions, suitable for harvesting at different periods of the crop season and for mechanized harvesting. Increased attention is given to the production of varieties which are self- or easy-trashing and those with increased fibre content for cogeneration.
It is expected that identification of molecular markers associated with disease resistance traits and agronomic characters will assist the breeding and selection programme while genetic transformation technology will allow the production of improved varieties. In vitro plantlets of new potato and sugar cane varieties are being used respectively to bulk minitubers for the seed potato scheme and for the establishment of disease-free sugar cane nurseries. Molecular diagnostic tools are applied for the early identification of pathogens in symptomless plants.
Technologies have been developed in plant pathology and entomology for sugar cane and associated food crops. The main diseases of sugar cane in Mauritius, namely gumming, leaf scald, yellow spot, smut and rust are kept under control by growing resistant varieties, using disease-free cuttings and by adopting sound cultural and sanitary practices. Control of pests relies essentially on long-term efforts for biological control though the introduction of parasites and predators.
The feasibility of growing other crops such as maize, groundnut, potato, bean and tomato on sugar cane lands has been studied, and appropriate varieties and cultural practices have been developed for intercropping and rotational cropping.
The Mauritius Herbarium was founded in 1960 and forms part of the Biology Sector of the MSIRI. It is the main repository of the Mascarene plant diversity and related bibliography available in the region. Apart from safeguarding these unique collections, The Mauritius Herbarium is involved in taxonomical and ecological projects, and supports both national and international research. Presently its most important ongoing project is the publication of the Flore des Mascareignes, in collaboration with the Royal Botanic Gardens, Kew (UK), and the Museum d’Histoire Naturelle de Paris. This project, which is also supported by l’Institut pour la Recherche et le Développement, was initiated in 1971 and is due to be completed in 2005.