impacts include crop failures, altered functioning of natural and manmade ecosystems, and species extinctions (Ewel et al., 1999). For example, in just one year the impact of the introduced golden apple snail (Pomacea canaliculata) on rice production cost the Philippine economy an estimated US$28-45 million, or approximately 40% of the Philippines' annual expenditure on rice imports (Naylor, 1996).

The late 20th century saw the emergence of highly virulent forms of wheat stem rust and cassava mosaic disease that are serious threats to food security.

The Ug99 race of Puccinia graminis, first discovered in East Africa, is virulent on most major resistance genes in wheat, which have provided effective worldwide protection against epidemic losses from wheat rust over the past 40 years (CIMMYT, 2005; Pretorius et al., 2002; Wanyera et al., 2006). Yield loss from Ug99 typically ranges from 40 to 80%, with some instances of complete crop failure (CIMMYT, 2005). The capacity for long-range wind dissemination of viable spores on the jet stream, the ubiquity of susceptible host germplasm, and the epidemic nature of wheat stem rust pose a significant threat to wheat producing regions of Africa and Asia, and possibly beyond. The Ug99 race recently crossed the Red Sea to Yemen, and is projected to follow a similar trajectory as the Yr-9-virulent wheat stripe rust, making its arrival in Central and South Asia possible within the next five or more years (CIMMYT, 2005; Marris, 2007).

Cassava mosaic virus (CMV) is a threat to a staple crop vital for food security.

In the late 1980s, CMV underwent recombinant hybridization of two less virulent virus types resulting in a severe and rapidly spreading form of cassava mosaic disease (Legg and Fauquet, 2004). CMD has expanded, via whitefly transmission and movement of infected planting stock, throughout East and Central Africa causing regional crop failure and famine (Mansoor et al., 2003; Anderson et al., 2004; Legg and Fauquet, 2004). CMD represents the first instance of a synergy between viruses belonging to the same family, which could confront agriculture with the future emergence of new and highly virulent geminivirus diseases (Legg and Fauquet, 2004). Cassava is important to future food security in Africa since it is hardy under normally low diseasepressure conditions, and has minimal crop management requirements. These qualities make it an emergency crop in conflict zones (Gomes et al., 2004), and a potentially important component of agricultural diversification strategies for adaptation to climate change.

Cereal cultivars resistant to insect pests have reduced yield losses.

Aphids, sun pest and Hessian fly are among the most serious pests of cereals worldwide (Miller et al., 1989; Ratcliffe and Hatchett, 1997; Mornhinweg et al., 2006). Hessian fly attacks result in yield losses of up to 30% in USA and Morocco, with estimated damage exceeding US$20 m per annum (Lafever et al., 1980; Azzam et al., 1997; Lhaloui et al., 2005). The most effective means of combating this pest has been found to be the development of cultivars with genes H1 to H31 for host plant resistance (antibiosis, antixenosis and tolerance) (Ratcliffe and Hatchett, 1997; Williams et al., 2003; Ohm et al., 2004). The development of wheat varieties resistant to the Hessian fly has been estimated to generate an internal rate of return of 39% (Azzam et al., 1997). A similar resistance approach has been taken with Russian wheat aphid, Diuraphis noxia) in wheat and barley in the US (Mornhinweg et al., 2006), and with soybean aphid (Aphis glycines). Storage pests, such as weevils, lower the quality of stored grain and seeds, and damage leads to secondary infection by pathogens, causing major economic losses. Host plant resistance has been identified against weevils, such as the maize weevil, Sitophilus zeamais and Callosobruchus spp., which also affect legumes e.g., cowpea (Dhliwayo et al., 2005).

Ethnoveterinary medicine for livestock could be a key veterinary resource.

Ethnoveterinary medicine (EVM) differs from the paternal approach by considering traditional practices as legitimate and seeking to validate them (Köhler-Rollefson and Bräunig, 1998). Systematic studies on EVM can be justified for three main reasons (Tabuti et al., 2003), they can generate useful information needed to develop livestock healing practices and methods that are suited to the local environment, can potentially add useful new drugs to the pharmacopoeia, and can contribute to biodiversity conservation.

3.2.1.2.3 Improving quality and postharvest techniques Traditionally, breeding was concerned primarily with yield, adaptation and disease/pest resistance rather than quality and postharvest processing traits. In recent years, more emphasis has been given to quality, especially user-defined quality (i.e., consumer acceptance), industrial processing and bioenhancement. In particular, more breeding programs are now focusing on fodder and forage quality, and not just grain quality.

Breeding for improved and enhanced quality is increasingly important.

Bioenhancement or biofortification is not a new concept, e.g., CIMMYT has worked on quality protein maize (QPM) for more than two decades, but concerns over micronutrient deficiencies (Bouis et al., 2000; Graham et al., 1999; www. harvestplus.org) in modern diets are driving renewed interest. Vitamin A deficiency affects 25% of all children under 5 in developing countries (i.e., 125,000 children), while aneimpacts