Unlike conventional sugar cane (Saccharum spp.) energy cane is a cane selected to have more fiber than sucrose in its composition. This is obtained simply by altering the genetic contribution of the ancestral species of sugarcane using traditional breeding methods. The resulting key feature is a significant increase in biomass yield. This happens because accumulating sugar is not physiologically a simple process and results in penalty in the side of fiber and yield. This review paper describes the initial conception of fuel cane in Puerto Rico in the second half of 1970s, the present resurgence of interest in it, how to breed energy cane, and the main characteristics that make it one of the most favorable dedicated bioenergy crops. The present status of breeding for energy cane in the world is also reviewed. Its potential contribution to the renewable energy market is discussed briefly.

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M&s, apple rootstocks, leaf mineral content, components of variance. SUMMARYThe relative effects of year to year variation and rootstock genotypes on the major content of leaves of four apple scion cultivars were studied. For nitrogen and phosphorus the main source of variation was due to years. For potassium, magnesium and calcium there were significant genetic effects. The results are discussed in relation to breeding for improved efficiency in mineral uptake in apple rootstocks. Particular reference is made to uptake of minerals associated with physiological disorders of stored apples.

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Modern sugarcane varieties are complex interspecific hybrids and are highly polyploid with a degree of aneuploidy. Although progress was initially good, by the 1960s it was realized that the exceedingly narrow genetic base of the existing clones was beginning to impede further progress. The need for the introduction of new genetic material into breeding programmes was generally accepted. Several new collections of wild relatives of sugarcane were made, particularly of Saccharum spontaneum. A wider collection of the cultivated forms of S. officinarum was also accumulated. This chapter describes a genetic base-broadening programme in the West Indies that utilizes this wide diversity of genetic material. Essentially, the programme repeats the nobilization stage of the crop's evolution, on a wider genetic base.