Apart from sugar production, the sugarcane plant is now viewed as a high value lowcost feedstock for renewable energy. However, in depth studies on the biomass potential of the crop are relatively new and current varieties have not been optimised to achieve the required high biomass yield for different end-uses. The objective of this study was to examine the possibility of using multivariate data analysis (MVDA) techniques in the selection of different types of high biomass canes. Sixty genotypes of different generations of crosses were evaluated for 18 inter-related traits. Principal component analysis compressed the different characters into five major principal components (PCs). The first two explained 77 % of total variation. PC1 emphasised on the cane quality traits while PC2 stressed on biomass characteristics. The biplot with the two PCs was very helpful in visualising the existing variations in the population. Cluster analysis defined six major groups in the population. Candidates from three of them were found suitable for commercial exploitation, for either sugar, fibre, or both as the main end-products. The MVDA techniques were thus found to be very effective in assessing the extent of genetic divergence between genotypes in the population and in the selection of different types of high biomass canes for multipurpose use. It was also clear that sucrose content was positively associated with cane diameter while high fibre varieties tended to be thinner and taller than the traditional commercial varieties.

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The rising need for crop diversification to mitigate the impacts of climate change on food security urges the exploration of crop wild relatives (CWR) as potential genetic resources for crop improvement. This study aimed at assessing the diversity of CWR of the Indian Ocean islands of Mauritius and Rodrigues and proposing cost-effective conservation measures for their sustainable use. A comprehensive list of the native species was collated from The Mauritius Herbarium and published literature. Each species was assessed for the economic value of its related crop, utilization potential for crop improvement, relative distribution, occurrence status and Red List conservation status, using a standard scoring method for prioritization. The occurrence data of the priority species were collected, verified, geo-referenced and mapped. A total of 43 crop-related species were identified for both islands and 21 species were prioritized for active conservation. The CWR diversity hotspots in Mauritius included Mondrain, followed by Florin and Le Pouce Mountain. Although a wide diversity of CWR has been recorded on both islands, most do not relate to major economic crops in use, therefore only a few species may be gene donors to economic crops at the regional and global level. For example, coffee, a major global beverage crop, has three wild relatives on Mauritius, which could potentially be of interest for future predictive characterization.

Significant genetic diversity for sucrose and fibre percentages exists in the species that served as the foundation of present day sugarcane cultivars. However, information is lacking worldwide on the recent contributions of sugarcane crop wild relatives (mainly Saccharum, Erianthus and Miscanthus wild species) in developing new varieties. There is renewed interest in using those relatives for creating new varieties to use as a dedicated bioenergy crop with higher fibre. This study focuses on past data analysis of sugarcane breeding in Mauritius with the objective to assess the efficiency in exploiting sugarcane wild relatives since 1970s to date. Pedigree analyses helped retrace the parentages of elite inter-specific hybrids reaching the final stages of selection. The studies confirmed the high prevalence of a few ‘wonder canes’ (successful hybrids with wild canes produced in the beginning of last century) among the ancestors of Mauritian varieties. Among the wild relatives, eight Saccharum spontaneum, two S. robustum, and one Erianthus clones were involved in generating elite genotypes worth evaluating at the advanced variety trial stages. A few early generation hybrids were released in the past for industrial exploitation, the latest one being M 1002/02 in 2016, with sugar as the primary output. Recent studies on the biomass potential and fibre yield of inter-specific hybrids are giving promising results, which expands the horizon in the use of sugarcane wild relatives for the generation of novel type of sugarcane varieties for multiple end-uses.

The use of near infrared spectroscopy, JEFFCO Infracana II, in the breeding and selection programme of the Mauritius Sugarcane Industry Research Institute (MSIRI) has led to a more reliable and rapid approach in estimating essential laboratory cane quality characters. The assessment of sucrose and fibre content now takes less than one minute per sample of cane with increased analytical precision and requiring considerably less labour. The latest calibration model in 2017 is based on approximately 3000 samples for Brix % cane, Pol % cane and fibre % cane. With this calibration model, the number of outliers generated that necessitate a separate laboratory analysis has been reduced to 5% or below. In fact, with the latest calibration model developed in 2018, the number of outliers has been considerable reduced and is now below 2%. The inclusion of more cane samples from high biomass and high sucrose sugar cane varieties will improve the robustness of the calibration models and further limit the number of outliers. Results from wet laboratory analyses were linearly regressed against those obtained from NIR giving a Pearson R2 values of 0.89 for Pol % cane, 0.90 for Brix % cane and 0.74 for fibre % cane.