Sustainable Agriculture and Soybean Breeding: Contribution of Soybean Yield Increase to Sustainable Agriculture
Soybean production has increased steadily in the USA since the beginning of twentieth century due to increases in yield (23.4 kg ha−1 year−1) and total area for soybean production (0.41 million ha year−1). This chapter discusses factors that influenced th
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Sustainable Agriculture and Soybean Breeding: Contribution of Soybean Yield Increase to Sustainable Agriculture Dusˇka Stojsˇin, Kevin W. Matson, and Richard A. Leitz
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Introduction
Continual human population growth has driven the need for increased food production worldwide. Greater food production was initially accomplished by increasing the area under cultivation. According to USDA statistical data (USDA-NASS 2011), farmland for soybean production increased almost 50-fold from 1924 to 2010 in the USA. This increase allowed for greater food and feed production, but it has also been associated with land degradation. More than 70 million cropland hectares eroded at rates higher than recommended for sustainable production (Hargrove et al. 1988). The limitation of land suitable for agricultural use, as well as farmland degradation due to misuse or overuse, made it necessary to focus on growing higher yielding crops on available crop land to lessen the demand to clear forested area for crop cultivation. Norman Borlaug estimated that if American farmers did not grow the high yielding crops available in recent decades, all the forest east of the Mississippi river would have to be cleared in order to produce the current food supply (Avery 1998). Globally, total area saved by modern agricultural systems was estimated to be almost 20 million square miles (Avery 1998). In this context, growing higher yielding crops is the most effective environmental conservation effort. The major factors contributing to soybean yield increases in the USA have been: genetic improvement of soybean varieties, optimization of agronomic practices, market trends, and government policies. Genetic improvement was estimated to D. Stojsˇin (*) Monsanto Company, Global Regulatory, 800 North Lindbergh Blvd., Mailzone V2C, St. Louis, MO 63167, USA e-mail: [email protected] K.W. Matson • R.A. Leitz Monsanto Company, Global Soybean Breeding, 800 North Lindbergh Blvd., Mailzone BB4A, St. Louis, MO 63167, USA e-mail: [email protected]; [email protected] D.D. Songstad et al. (eds.), Convergence of Food Security, Energy Security and Sustainable Agriculture, Biotechnology in Agriculture and Forestry 67, DOI 10.1007/978-3-642-55262-5_9, © Springer-Verlag Berlin Heidelberg 2014
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have contributed 45–50 % to the realized yield gain for soybean (Luedders 1977; Specht and Williams 1984). Most genetic changes contributed to improved pest resistance (Hartwig 1973; Riggs 2004; Parrott et al. 2008), alteration of plant morphology (Specht and Williams 1984; Boerma 1979), changes in plant physiology (Specht et al. 1999; Morrison et al. 2000; De Bruin and Pedersen 2009), or introduction of herbicide-tolerant varieties (Fernandez-Cornejo and Caswell 2006). These higher yielding varieties contributed to environmental protection not only via preservation of land needed for soybean production but also by reducing the need for chemical pest control (due to introduction of disease-resistance, insect-resistance or
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