Sugarcane crops Plant growth promoting bacteria in growth, yield and productivity

Abstract

Sugarcane is an important industrial and cash crop in many countries of the world. It is grown in over 110 countries, in tropical and sub-tropical regions, in a range of climates from hot dry environment near sea level to cool and moist environment at higher elevations. Besides sugar production, sugarcane produces numerous valuable by-products like ethanol, bagasse, press mud, molasses, and essential items for industries like chemicals, plastics, paints, synthetics, fiber, insecticides, and detergents (http://www.pakissan.com). This crop is perhaps the most economically competitive source of ethanol and can effectively contribute to a cleaner environment. Ways of improving its productivity are subject to investigation in several countries. Worldwide climate change due to the intense use of greenhouse gasproducing energy sources has resulted in the development of sustainable energy. Consequently, sustaining and enhancing the growth and yield of sugarcane have become a major focus of research. Sugarcane and other grasses such as rice, wheat, maize, and sorghum, currently have much of their nitrogen (N) needs supplied by costly mineral fertilizers. It has been a general practice to apply 250 kg N ha 1 year 1 , or more in most of the sugarcane cultivating countries. In 2008, an estimated 1,743 million metric tons of sugarcane were produced worldwide, with about 50% of production occurring in Brazil and India. In India, sugarcane is grown over 4.2 million ha, producing about 250 million tons of canes annually and the nitrogen requirement of Indian sugarcane ranges from about 250 to 350 kg ha 1 . Brazil is the largest sugarcane producer in the world, with the crop occupying more than five million hectares with a yield of 495 M tons in 2007/2008 (UNICA 2009), 16 million m3 of alcohol in 2006 (Mendes et al. 2007; Oliveira et al. 2006) and annual application of nitrogen fertilizer for sugarcane is around 50 kg N ha 1 , with a cost near US$ 500 t 1 (http://www.udop. com.br). Researchers in Brazil are intensively working on further reducing the use of N-fertilizer application by one half (<125,000 t N year 1 ) due to the biological nitrogen fixation (BNF), so the producers could save estimated US$ 62.5 m year 1 (Oliveira et al. 2006). This approach can significantly reduce the cost of bio-energy in the whole world.