China is the world's leading producer of potatoes, growing 22% of all potatoes. Production continues to rise, owing to increases in both land devoted to potato production and yield per hectare. Most potato production occurs in the northern and southwest regions of the country. The processing of coarse starch is the most important component of the potato processing industry in China, but other processing industries, such as crisps and French fries, are expanding. Major production constraints include inadequate germplasm resources for cultivar development, the lack of high quality seed potatoes, and limited access to equipment for mechanized cultivation, planting, fertilizing, spraying, and harvesting. Additional weaknesses in storage and transportation technologies must be addressed, as they are the major constraints for the healthy development of the potato industry. The introduction and improvement of these technologies will ensure the sustainable development of the potato industry in China.

Phenotypic and genotypic characteristics of 48 Phytophthora infestans isolates, collected in five provinces in Northern China between 1997 and 2003, were determined and compared with reference isolates. Characterisation included mating type, virulence, mitochondrial DNA (mtDNA) haplotype and DNA fingerprinting patterns based on simple sequence repeats (SSR) and amplified fragment length polymorphisms (AFLP). All isolates had the A1 mating type, mtDNA haplotype IIa and an identical SSR genotype (designated as SG-01-01) that differed from SSR genotypes found in the reference isolates, including those representing the 'old' US-1 lineage that dominated the P. infestans population worldwide prior to 1980. In contrast, the virulence spectra were highly variable and virulence to all resistance genes present in the standard differential set (R1 to R11) was found. AFLP analysis revealed some diversity; eight different AFLP genotypes were found that could be grouped into two major clusters. This study shows that there is very little genotypic diversity in the P. infestans population in Northern China. The occurrence of many different races within this rather uniform population is discussed in the framework of recent insights into the molecular determinants of avirulence in potato-P. infestans'gene-for-gene' interactions.

Although nonspecific lipid transfer proteins (nsLTPs) are widely expressed during plant defence responses to pathogens, their functions and regulation are not fully understood. In this article, we report the isolation of a cDNA for the new nsLTP, StLTPa7, from cultivated potato (Solanum tuberosum) infected with Ralstonia solanacearum. The cDNA was predicted to encode a type 1 nsLTP containing an N-terminal signal sequence and possessing the characteristic features of nsLTPs. A phylogenetic analysis showed that the encoded amino acid sequence of the nsLTP was similar to those of other previously reported plant nsLTPs, which contain a putative calmodulin-binding site consisting of approximately 12 highly conserved amino acid residues. The expression of the StLTPa7 gene was studied during the early stages of potato-R. solanacearum interaction using real-time quantitative polymerase chain reaction (qRT-PCR) and Northern analyses, and a complex calcium (Ca2+)-associated pattern of expression was observed with the following features: (i) transcripts of the StLTPa7 gene were systemically up-regulated by infection with R. solanacearum; (ii) the StLTPa7 gene was stimulated by salicylic acid, methyl jasmonate, abscisic acid and Ca2+; (iii) qRT-PCR showed that, during the early stage of R. solanacearum infection, nsLTP transcripts accumulated over a time course that paralleled that of Ca2+ accumulation, detected using environmental scanning electron microscopy and energy-dispersive X-ray (EDAX) spectrometry; and (iv) the Ca2+ channel blocker, ruthenium red, partially blocked R. solanacearum-induced StLTPa7 expression. This report represents the first use of EDAX analysis to establish a synchrony between Ca2+ accumulation and nsLTP expression in response to potato-R. solanacearum interactions. Collectively, these results suggest that StLTPa7 may be a pathogen- and Ca(2+)-responsive plant defence gene.

In the 1990s, the integrated pest management (IPM) team for potato late blight (IPM-late blight) at the International Potato Center (CIP) began to address the management of this complex potato disease by combining crop protection with social and behavioral sciences. Since the early 2000s, the team has worked with research and development organizations in countries in Asia, sub-Saharan Africa, and South America to develop farmer discovery-based learning methods using farmer field schools (FFS). The principles of late blight control were more visible and understood by farmers when they could test options for managing late blight, particularly new potato clones with resistance to the disease, for themselves. CIP and partners have since adapted an approach combining FFS and participatory research to facilitate farmers’ access to information, knowledge, and technologies. Several manuals to implement FFS-IPM-late blight with farmers were subsequently developed. Results indicated that farmers using this approach learned new knowledge, assessed new potato clones, and changed crop management practices. Hence farmers realized a 32% average increase in potato productivity and income in Peru; similar changes occurred in other countries. The participatory research and training approach had a significant impact beyond IPM-late blight. In Peru and Bolivia, for example, more than 2,000 FFS were implemented between 2005 and 2012 on IPM for potato, other crops (coffee, cocoa, fruit trees), and livestock. In Uganda and Ethiopia, the experience expanded to potato seed management with the formation of seed cooperatives. Lessons have been drawn from this experience.