International Potato Center

About: International Potato Center is a facility organization based out in Lima, Peru. It is known for research contribution in the topics: Population & Phytophthora infestans. The organization has 1036 authors who have published 1460 publications receiving 47183 citations.

Insect pests of sweetpotato in Uganda: farmers’ perceptions of their importance and control practices

Abstract: Insect pests are among the most important constraints limiting sweetpotato (Ipomoea batatas) production in Africa. However, there is inadequate information about farmers’ knowledge, perceptions and practices in the management of key insect pests. This has hindered development of effective pest management approaches for smallholder farmers. A standard questionnaire was used to interview individual sweetpotato farmers (n = 192) about their perception and management practices regarding insect pests in six major sweetpotato producing districts of Uganda. The majority (93%) of farmers perceived insect pests to be a very serious problem. With the exception of Masindi and Wakiso districts where the sweetpotato butterfly (Acraea acerata) was the number one constraint, sweetpotato weevils (Cylas puncticollis and C. brunneus) were ranked as the most important insect pests. Insecticide use in sweetpotato fields was very low being highest (28–38% of households) in districts where A. acerata infestation is the biggest problem. On average, 65% and 87% of the farmers took no action to control A. acerata and Cylas spp., respectively. Farmers were more conversant with the presence of and damage by A. acerata than of Cylas spp. as they thought that Cylas spp. root damage was brought about by a prolonged dry season. Different levels of field resistance (ability of a variety to tolerate damage) of sweetpotato landraces to A. acerata (eight landraces) and Cylas spp. (six landraces) were reported by farmers in all the six districts. This perceived level of resistance to insect damage by landraces needs to be investigated. To improve farmers’ capabilities for sweetpotato insect pest management, it is crucial to train them in the basic knowledge of insect pest biology and control.

Protocol for DNA extraction from potato tubers

Abstract: A method to extract high-quality DNA from potato tubers was developed and tested on 3 wild potato species (Solanum raphanifolium, S. megistracrolobum, S. bukasovii) and on the tetraploid B3 bred population, (population number 393228, derived fromS. tuberosum subsp.tuberosum). The average yield of extracted DNA varied from 10–30 μg of DNA per gram of processed tissue. The DNA was pure and suitable for ligation-mediated polymerase chain reaction (LM-PCR) amplification, producing clear, distinctive, and reproducible banding patterns in polyacrylamide gels.

Some studies on the distribution and incidence of potato mop-top virus in Peru

Abstract: Symptoms of PMTV are distributed widely in potatoes in the highlands (Andes) of Peru, but have not been found in coastal plantings; they were observed in 9 out of 22 Peruvian Departments. Incidences of over 10% of affected plants in one or more crops were found in 14 different localities. Thirteen cultivars with symptoms were observed, 9 wereSolanum tuberosum subsp.andigena Juz. & Buk., 3 were hybrids ofS. tuberosum subsp.andigena xS. tuberosum subsp.tuberosum L orS. Curtilobum Juz. & Buk. and 1 wasS. juzepczukii Buk. Symptoms were also seen in 29 clones of the potato germplasm collection of the International Potato Center. Distribution and prevalence of PMTV in Peru appear to be related to those rainfall and temperature conditions that favour its fungus vectorSpongospora subterranea (Wallr.) Lagerh.

Tropical maize (Zea mays L.).

Abstract: From its origins in Mexico, maize has spread throughout the cropping world and now has the largest annual production of any cereal crop. Maize adapted to the tropics has a shorter breeding history than its temperate equivalent, and maize yields in the tropics average 46% those of temperate regions. Diverse microclimates in its center of origin in Mexico resulted in a great diversity of landraces, and early improvement focused on identifying and compositing the most productive of these into genetically diverse populations that have subsequently formed the basis of modern inbred line extraction and pedigree breeding. The International Maize and Wheat Improvement Center (CIMMYT) has been the focus of much of this research for the past 50 years, and they, along with multinational seed companies, have been largely responsible for the major movements of elite tropical maize germplasm to Africa and Asia. Crop improvement has focused primarily on changing biomass partitioning by reducing plant height, increasing ear growth, reducing barrenness, and consistently focusing on increasing biotic and abiotic stress tolerances. Photoperiod sensitivity and tassel size, however, remain high and harvest index and tolerance to plant density low relative to temperate maize. Tropical maize breeding programs have shown genetic gains of around 100 kg/ha/year under optimal conditions, though less under abiotic stress. Genetic rates of gain have averaged 1–2% annually despite the high incidence of stresses in target environments, and today farm yields in tropical environments are increasing at the same rate (70–80 kg/ha/year) as in temperate production areas. Although open-pollinated varieties (OPVs) have been largely superseded by hybrids, there are niches in low-yielding environments or where commercial seed companies are dysfunctional where OPVs have a role. Tropical maize breeding programs should maintain their focus on yield stability in stressed environments, increased yield potential by further changes in plant morphology and partitioning, precise high-throughput phenotyping, and the systematic adoption of real-time marker-assisted selection (MAS). Considerable improvements in technologies that shorten the selection cycle have been made, e.g., the combination of doubled haploid inbred line production and MAS, especially genomic selection. Effective management of the deluge of genotypic and phenotypic data is a continuing priority. Impact will however only be achieved by increasing the rate of varietal turnover at the farm level so the challenges of global warming can be effectively met by the new generation of stress-tolerant maize cultivars. This can only come about through effective private-public partnerships in the seed sector and in a continued investment in well-trained motivated plant breeders and agronomists committed to quality fieldwork with the widest possible array of useful genetic variation.

Nutrient-dense orange-fleshed sweetpotato: advances in drought-tolerance breeding and understanding of management practices for sustainable next-generation cropping systems in Sub-Saharan Africa

Abstract: Almost half of children < 5 years old living in sub-Saharan Africa (SSA) suffer from vitamin A deficiency and 60% suffer from iron deficiency. Thus, there has been a strong commitment to breeding for, promoting awareness of, and delivering adapted pro-vitamin A rich orange-fleshed sweetpotato (OFSP) in SSA during the past two decades and for enhanced iron content since 2014. This review article focuses on major breeding efforts in SSA to enhance the drought tolerance of OFSP and reviews integrated crop management practices for improved and sustained sweetpotato production in SSA farming systems. Under climate change, the frequency and severity of droughts is expected to increase. Technical issues are presented in the context of addressing challenges along the entire value chain to ensure adoption. First, the use of an accelerated breeding scheme reduced the breeding cycle from 8–10 to 4–5 years. Since 2010, 19 drought-tolerant OFSP cultivars have been released in Mozambique, 7 in Malawi, and 2 in South Africa. Moreover, research in four breeding populations using the heterosis exploiting breeding scheme (HEBS) demonstrated that within one breeding cycle of 5 years, clones with significantly higher root yield, abiotic tolerance, host plant resistance to pests and diseases, and early maturity can be produced. In the future, HEBS will be combined with greater use of modern genomic tools, new phenotyping tools, and CRISPR/Cas9-mediated gene editing. Second, beyond genetic enhancements, evidence is presented that using improved crop management systems, existing sweet potato yields can be increased 2–4 times. Current knowledge is reviewed concerning sweetpotato’s role in diverse farming systems, but integrated crop management is clearly under researched. Third, the outlook for drought tolerance breeding indicates that two distinct classes of nutrient-rich cultivars are emerging: (1) Early maturing cultivars (< 4 month growing period) that escape drought but also serve humid environments with small landholding size per capita; and (2) Medium maturing (4–6 month growing period) cultivars that avoid drought, are drought tolerant and exhibit continuous root formation. Increasing commercialization of the crop and climate change will drive demand, and the willingness of farmers to invest in improved sweetpotato crop management.