Pathogen biology. Cell biology of pathogenesis. Signalling systems and gene expression regulating appressorium formation in magnaporthe grisea. Genetic regulation of sporulation in the rice blast fungus. Genetic interactions in magnaporthe grisea that affect cultivar specific avirulence/virulence on rice. Genomic structure and variability in pyricularia grisea. Molecular genetic approach to the study of cultivar specificity in the rice blast fungus. Avirulence genes and mechanisms of genetic instability in the rice blast fungus. Host plant resistance. International collaboration on breeding for resistance to rice blast. Present knowledge of rice resistance genetics and strategies for magnaporthe grisea pathogenicity and avirulence gene analysis. Mapping of blast resistance genes in rice. Molecular genetic analysis fo the rice bacterial blight resistance locus, Xa21. Current status for gene transfer into rice utilizing variety-independent delivery systems. Pathogen population dynamics and utilization of host plant resistance. Virulencecharacteristics of genetic families of pyricularia grisea in Colombia. Race-specific and rate-reducing resistance to rice blast in US rice cultivars. A strategy for accumulating genes for partial resistance to blast disease in rice within a conventional breeding program. Lineage exclusion: a proposal for linking blast population analysis to resistance breeding. Use of host genetic diversity to control cereal diseases: implications for rice blast. Figs, wasps, nematodes and sitting ducks: rice blast, from the outside looking in. Epidemiology, loss assessment, and management. The economic impact of rice blast disease in China. Current rice blast epidemics and their management in Thailand. Rice blast in west Africa: its nature and control. Understanding and modeling leaf blast effects on crop physiology and yield. Methodology for quantifying rice yield effects of blast. The epidemiological basis for blast management. Using simulation models to explore better strategies for the management of blast disease in temperate rice pathosystems. Blast management in high input, high yield potential, temperate rice ecosystems. Practical approaches to rice blast management in tropical monsoon ecosystems, with special reference to Bangladesh. Rice breeding programs, blast epidemics and blast management in the United States. Strategies for the discovery of rice blast fungicides. Biological control of rice leaf blast. Farmers' perspectives. Crop-livestock interactions: implications for crop improvement in sustainable agriculture. Assessing indigenous and traditional knowledge in farming systems. Rice, reason, and resistance: a comparative study of farmers' vs. Scientists' perception and strategies.

In large parts of the developed and developing worlds soil tillage by plough or hoe is the main cause of land degradation leading to stagnating or even declining production levels and increasing production cost. It causes the soil to become more dense and compacted, the organic matter content to be reduced and water runoff and soil erosion to increase. It also leads to droughts becoming more severe and the soil becoming less fertile and less responsive to fertiliser. This book brings together the key notes lectures and other outstanding contributions of the I World Congress on Conservation Agriculture and provides an updated view of the environment and economic advantages of CA and of its implementation in diferent areas of the World.

The estimated present value (US$42 million) of the proposed ILRI/ICRISAT/NARS collaborative research project on genetic improvement of millet and sorghum crop residues indicates fairly attractive returns, even with the cautious assumption made about likely adoption rates and the scope of the benefits (i.e. only meat and milk production in cattle in India). The estimated IRR to this research investment (28%) can be compared to market rates on alternative investments. Most longer-run, low-risk, private-sector investments yield rates of return three times as high as alternative investments. However, this raises the question of what is an appropriate rate of return to expect from 'public'good' type of investment such as the investment in international development oriented research. The same methodological approach was recently used (Kristjanson et al 1999) to estimate potential returns to a similary challenging crop-livestock research area, a vaccine against potential returns to a similarly challenging crop-livestock research area, a vaccine against trypanosomosis (a serious livestock disease that poses the greatest development constraint to mixed livestock-crop systems across Africa). Potential returns to this research were estimated at US$ 118 million, with an IRR of 25%, and a benefit:cost ratio of 15:1. In a comparison of predicted rates of return across 5 crop-livestock related research areas at ILRI, potential research benefits were estimated to outweigh the costs of the research by between 9 and 37 times. Returns of similar magnitudes have also been estimated for other crop improvement research. In an economic analysis of returns to 15 research themes at the Centro International de la Papa (CIP) the NPVs ranged from US$ 1 million to US$ 195 million (average US$ 67 million), with IRRs ranging from 13% to 51% (Walker and Collion 1997). ICRISAT ranked returns to 110 different research areas as part of their research priority-setting process several years ago. The average NPV, net benefit:cost ratio and IRR for the top 20 of those were US$ 61 million (with a range from US$ 8 million to US$ 265 million), 52:1 and 39%, respectively (Kelley et al 1995). Thus it appears that the magnitude of returns predicted in this study are very much in line with returns to similar research investments.