Time filter

Source Type

Chinchiná, Colombia

Tinoco H.A.,Autonomous University of Manizales | Ocampo D.A.,Autonomous University of Manizales | Pena F.M.,Autonomous University of Manizales | Sanz-Uribe J.R.,National Coffee Research Center
Computers and Electronics in Agriculture

This study shows a heuristic process for identification of natural frequencies and modes of vibration of the fruit-peduncle system of Coffea arabica L. var. Colombia by means of a modal analysis. From experimental data, the real topology of the fruit-peduncle system was approached with a proposed theoretical model. The geometric models can be generated in any ripening stage and these showed a good agreement when these are compared with real coffee fruits. The elastic properties of the fruit were determined from a sensitive analysis using experimental data of firmness for each ripening stage. It was observed that with the increase in the days of ripening, the fruit loses its elastic capacity. From a finite element modal analysis, the natural frequencies were identified for the fruit-peduncle system and the first 20 modes of vibration were selected and analyzed. A dynamic criterion was established to identify and define frequency intervals in which the modes of vibration produce rotations at the fruit-pedicel interface. The results shows that the modes associated to natural frequencies in specific intervals probably facilitate the separation between the interface fruit-pedicel for the ripe stage but these intervals are different from other ripening stages. The heuristic process developed in this study may be extrapolated to other varieties of coffee. © 2014 Elsevier B.V. Source

Castro Caicedo B.L.,University of Pretoria | Cortina Guerrero H.A.,National Coffee Research Center | Roux J.,University of Pretoria | Wingfield M.J.,University of Pretoria
Tropical Plant Pathology

The purpose of this study was to evaluate the resistance to coffee leaf rust (CLR) caused by Hemileia vastatrix and to Ceratocystis canker (Cc) in coffee genotypes derived from crosses of Coffea arabica var. Caturra with accessions of C. canephora backcrossed to Caturra. Twenty-three F3BC1 progenies including C. arabica var. Caturra and var. Colombia as controls were established in a field experiment. CLR evaluations were made during five years of natural infection, using an incidence rating scale. For Cc, artificial stem inoculations were made with an isolate of Ceratocystis colombiana and the results were assessed after one year. The selection process also included agronomic aspects such as plant height, canopy diameter, number of branch pairs, yield and grain characteristics. Twenty progenies showed >70% of rust resistance. Twelve progenies exhibited >80% of Cc resistance, while no resistance was observed in either of the controls. Only three progenies performed well for all criteria, including resistance to both pathogens and agronomic characteristics. © by the Brazilian Phytopathological Society. Source

Neu A.-K.,Leibniz Institute for Agricultural Engineering | Pleissner D.,Leibniz Institute for Agricultural Engineering | Mehlmann K.,Leibniz Institute for Agricultural Engineering | Schneider R.,Leibniz Institute for Agricultural Engineering | And 2 more authors.
Bioresource Technology

In this study, mucilage, a residue from coffee production, was investigated as substrate in fermentative l(+)-lactic acid production. Mucilage was provided as liquid suspension consisting glucose, galactose, fructose, xylose and sucrose as free sugars (up to 60 g L-1), and used directly as medium in Bacillus coagulans batch fermentations carried out at 2 and 50 L scales. Using mucilage and 5 g L-1 yeast extract as additional nitrogen source, more than 40 g L-1 lactic acid was obtained. Productivity and yield were 4-5 g L-1 h-1 and 0.70-0.77 g lactic acid per g of free sugars, respectively, irrespective the scale. Similar yield was found when no yeast extract was supplied, the productivity, however, was 1.5 g L-1 h-1. Down-stream processing of culture broth, including filtration, electrodialysis, ion exchange chromatography and distillation, resulted in a pure lactic acid formulation containing 930 g L-1 l(+)-lactic acid. Optical purity was 99.8%. © 2016 Elsevier Ltd. Source

Gartner G.A.L.,University of Caldas | McCouch S.R.,Cornell University | Moncada M.D.P.,National Coffee Research Center

Coffee is globally one of the most important export crops and is a prominent part of the economy in more than 50 countries in Latin America, Africa and Asia. In Colombia, it has been the leading export commodity for more than a century. However, genetic research on coffee has been rather sparse and mainly focused on the two major cultivated species, Coffea arabica L. and C. canephora P., leaving unexplored the genetic potential in other species. In this study, an interspecific mapping population consisting of 101 F1 hybrid plants from a cross between the diploid species C. liberica and C. eugenioides was evaluated for genetic segregation at 618 molecular marker loci. Of these, 168 SSRs and two ESTs exhibited polymorphic patterns that allowed segregation analysis and genetic linkage estimations. A genetic map consisting of 146 co-dominant loci and 11 predicted linkage groups was constructed using the mapping software JoinMap 3.0. The conjoined maternal/paternal map length is 798.68 cM, has an average saturation density of 6.01 cM/interval, and covers an estimated 66-86 % of the diploid coffee genome. Approximately 24 % of loci had null alleles, and 23.5 % exhibited segregation distortion. Knowledge derived from this study has important applications for quantitative trait locus analysis and marker-assisted selection in Colombian coffee breeding programs. © 2013 Springer Science+Business Media Dordrecht. Source

Avelino J.,CIRAD - Agricultural Research for Development | Avelino J.,Tropical Agriculture Research and Higher Education Center | Cristancho M.,National Coffee Research Center | Georgiou S.,Tropical Agriculture Research and Higher Education Center | And 7 more authors.
Food Security

Coffee rust is a leaf disease caused by the fungus, Hemileia vastatrix. Coffee rust epidemics, with intensities higher than previously observed, have affected a number of countries including: Colombia, from 2008 to 2011; Central America and Mexico, in 2012–13; and Peru and Ecuador in 2013. There are many contributing factors to the onset of these epidemics e.g. the state of the economy, crop management decisions and the prevailing weather, and many resulting impacts e.g. on production, on farmers’ and labourers’ income and livelihood, and on food security. Production has been considerably reduced in Colombia (by 31 % on average during the epidemic years compared with 2007) and Central America (by 16 % in 2013 compared with 2011–12 and by 10 % in 2013–14 compared with 2012–13). These reductions have had direct impacts on the livelihoods of thousands of smallholders and harvesters. For these populations, particularly in Central America, coffee is often the only source of income used to buy food and supplies for the cultivation of basic grains. As a result, the coffee rust epidemic has had indirect impacts on food security. The main drivers of these epidemics are economic and meteorological. All the intense epidemics experienced during the last 37 years in Central America and Colombia were concurrent with low coffee profitability periods due to coffee price declines, as was the case in the 2012–13 Central American epidemic, or due to increases in input costs, as in the 2008–11 Colombian epidemics. Low profitability led to suboptimal coffee management, which resulted in increased plant vulnerability to pests and diseases. A common factor in the recent Colombian and Central American epidemics was a reduction in the diurnal thermal amplitude, with higher minimum/lower maximum temperatures (+0.1 °C/-0.5 °C on average during 2008–2011 compared to a low coffee rust incidence period, 1991–1994, in Chinchiná, Colombia; +0.9 °C/-1.2 °C on average in 2012 compared with prevailing climate, in 1224 farms from Guatemala). This likely decreased the latency period of the disease. These epidemics should be considered as a warning for the future, as they were enhanced by weather conditions consistent with climate change. Appropriate actions need to be taken in the near future to address this issue including: the development and establishment of resistant coffee cultivars; the creation of early warning systems; the design of crop management systems adapted to climate change and to pest and disease threats; and socio-economic solutions such as training and organisational strengthening. © 2015, The Author(s). Source

Discover hidden collaborations