Biological Nitrogen Fixation in Sugarcane

Abstract

Sugarcane, Saccharum and related genera, belongs to the grass family known until 2001 as Gramineae (Ellis, 1986; Reeder, 1957). In 2001, the Grass Phylogeny Working Group (GPWG) developed a robust phylogeny of the family based on the evolutionary relationships among grasses as well as the structure of grass genomes. The new name of the family is Poaceae, subfamily Panicoide, based on nuclear markers (Gaut, 2002). Currently, this crop is cultivated in the belt 35°N to 35°S and from sea level to 1000m altitude on a wide diversity of soil types (Malavolta, 1994). It is used mainly for sugar and alcohol production. Around 327 BC, it was an important crop in the Indian subcontinent (Aranha and Yahn, 1987). The approximate center of New Guinea is considered as the home of the officinarum species, with its migration occurring mostly by primitive people carrying the sweetest canes with them as they travelled to India, Burma, Indochina, Indonesia, the Solomon Islands, New Caledonia, and Hawaii (Clements, 1980). It has been cultivated in over 120 countries and among member countries of the Food and Agriculture Organization (FAO) of United Nations. It is cropped on an area of 19,682,410 hectares (FAO, 2002). The major sugarcane producers are based in larger countries, such as Brazil (360,556,000 tons) and India (279,000,000 tons), however, the highest yields at more than 100 t ha are obtained in countries like Peru, Egypt, and Senegal, compared to Australia and Brazil at only ca. 75 t ha. In Brazil, sugarcane is planted on more than 5.2 million ha, 9% of the land under cropping. In 2001, the country exported 11,528 million tons of sugar. Generally, one third of the cane production is directed to the manufacture of hydrated ethanol (95%) representing 12-14 billion L year. Industrial processing occurs in more than 300 mills/distilleries, all of which are privately owned, and represents an