La recherche agronomique sur Coffea arabica a débuté en 1933 dans la région des Grands Lacs. Elle... more La recherche agronomique sur Coffea arabica a débuté en 1933 dans la région des Grands Lacs. Elle s'est fortement développée au Burundi à partir de 1979 avec la mise en place d'un large programme de recherche. A présent, toutes les régions caféicoles du pays sont intégrées dans des activités de recherche très diversifiées qui tentent de répondre à l'ensemble de la problématique posée par la culture du caféier arabica au Burundi. En culture pérenne, les résultats expérimentaux fiables ne sont obtenus qu'après de nombreuses années de travail, quelquefois plus de vingt ans. Néanmoins, des résultats de recherche ont déjà été obtenus dans les domaines de la sélection variétale, des techniques culturales, de la fertilisation, de la défense de la culture et de l'étude socio-économique du milieu paysan producteur. (Résumé d'auteur)
The quality of coffee is influenced by many factors such as coffee variety, agricultural and post... more The quality of coffee is influenced by many factors such as coffee variety, agricultural and postharvest conditions, roasting parameters, and brewing. The pleasure of drinking coffee may be affected by off-notes such as burnt, green, earthy, or fermented. Their presence is related to the variety, fermentation during postharvest processing, or over-roasting of the beans. Sensory expert panels trained for the evaluation of coffee are able to detect off-notes and select coffees by well-defined quality criteria. The application of instrumental approaches detecting quality markers related to the perceived off-notes is shown to be useful to assist sensory panels. This paper describes the discovery of a new marker compound related to the fermented off-note occasionally perceived in coffees. The application of untargeted chemometric methods on volatile compounds revealed correlations between individual compounds and the sensory attribute. The new marker compound was identified as ethyl formate, which can be measured in the headspace of roasted and ground coffee by various analytical techniques including online proton transfer reaction mass spectrometry.
In Vitro Cellular & Developmental Biology - Plant, 2007
ABSTRACT The objective was to set up a pilot scale process for robusta (Coffea canephora) industr... more ABSTRACT The objective was to set up a pilot scale process for robusta (Coffea canephora) industrial propagation by somatic embryogenesis in liquid media. A batch production of pre-germinated embryos was initiated once every 2mo. in 2003 and 2004, then every mo. in 2005. Each run batch requires 4 to 6mo. to produce the pre-germinated somatic embryos and consists of three phases: (1) the development of torpedo stage embryos in Erlenmeyer flasks, (2) pre-germination in temporary immersion bioreactors to allow maturation from the torpedo stage to the cotyledonary stage, (3) maintaining the embryos under storage conditions before their shipment to coffee producing countries. Starting from 1kg of embryogenic calluses, a total of 4.4 million pre-germinated embryos for 17 clones were produced over 3yr. This embryo number was enough to potentially regenerate 2 million plants, as the global embryo-to-plantlet conversion rate was estimated to 46% after acclimatization and complete germination in the greenhouse. At the end of April 2006, 600,000 somatic seedlings were transferred into plastic bags in nurseries or were already planted in the fields, mainly in Thailand. The current capacity allows the production of 2.5 million embryos per year, equivalent to a potential of about 1.0 million plantlets. The technical package has recently been transferred to National Institutes in Mexico, Thailand, and Vietnam.
Coffea canephora is subject to enormous competitive challenges from other crops, especially for f... more Coffea canephora is subject to enormous competitive challenges from other crops, especially for farmer sustainability and consumer requirements. Coffee breeding programs have to focus on specific traits linked to these two key targets, such as quality character, largely depending on the bean's biochemical composition and field yield. Two segregating populations A and B, from crosses between a hybrid (Congolese×Guinean) FRT58 parental clone and a Congolese FRT51 genotype and between two Congolese parents FRT67 and FRT51, respectively, were used to characterize the quantitative trait loci (QTL) involved in agronomic and biochemical traits. A consensus genetic map was established using 249 SSRs covering 1,201 cM. Three QTL detection models per population with MapQTL (model I) and MCQTL (model II) followed by a connected population approach with MCQTL (model III) were compared based on their efficiency, precision for QTL detection, and their genetic effect assessment (additive, dominance, and parental-favorable allele). The analysis detected a total of 143 QTLs, 60 of which were shared between the three models; 28 found with two models; and two, 13, and 40 specific from models I, II, and III, respectively. The last model III based on connected populations is much more efficient in detecting QTLs with low variance explained and led to the genetic characterization of favorable allele. Thanks to this comparison of three QTL detection models on our quantitative genetic study, we will give a new insight for coffee breeding programs dedicated to managing complex agronomic or qualitative traits.
The purpose of the study was to evaluate the possible genetic effect on vegetative propagation of... more The purpose of the study was to evaluate the possible genetic effect on vegetative propagation of Coffea canephora. Diversity for somatic embryogenesis (SE) ability was observed not only among two groups of C. canephora Pierre (Congolese and Guinean), but also within these different genetic groups. The results therefore showed that, under given experimental conditions, SE ability is depending on genotype. Furthermore the detection of quantitative trait loci (QTLs) controlling the SE and cutting abilities of C. canephora was performed on a large number of clones including accessions from a core collection, three parental clones and their segregating progenies. On the one hand we detected eight QTLs determining SE. Six positive QTLs for SE ability, whatever the criteria used to quantify this ability, were localized on one single chromosome region of the consensus genetic map. Two negative QTLs for SE ability (frequency of micro calli without somatic embryo) were detected on another linkage group. Deep analysis of the six QTLs detected for SE ability came to the conclusion that they can be assimilated to one single QTL explaining 8.6-12.2% of the observed variation. On the other hand, two QTLs for average length of roots and length of the longest sprouts of cuttings were detected in two linkage groups. These QTLs detected for cutting ability are explaining 12-27% of the observed variation. These observations led to conclude that SE and cutting abilities of C. canephora Pierre appeared to be genetic dependent but through independent mechanisms.
Considerable work has been devoted in the last decades to the identification and quantification o... more Considerable work has been devoted in the last decades to the identification and quantification of key aroma-active compounds in coffee as well as their precursors. The aim of this work was to demonstrate the applicability of a data-driven holistic method rather than a targeted chemical study. As an illustrative example, coffees at different roast degrees were analysed with a range of instrumental techniques (LC-MS, GC-MS, PTR-MS) and evaluated by a sensory panel. This allowed identifying correlations between chemical markers and sensory qualities and developing a deeper understanding on reaction mechanisms involved in coffee aroma formation.
La recherche agronomique sur Coffea arabica a débuté en 1933 dans la région des Grands Lacs. Elle... more La recherche agronomique sur Coffea arabica a débuté en 1933 dans la région des Grands Lacs. Elle s'est fortement développée au Burundi à partir de 1979 avec la mise en place d'un large programme de recherche. A présent, toutes les régions caféicoles du pays sont intégrées dans des activités de recherche très diversifiées qui tentent de répondre à l'ensemble de la problématique posée par la culture du caféier arabica au Burundi. En culture pérenne, les résultats expérimentaux fiables ne sont obtenus qu'après de nombreuses années de travail, quelquefois plus de vingt ans. Néanmoins, des résultats de recherche ont déjà été obtenus dans les domaines de la sélection variétale, des techniques culturales, de la fertilisation, de la défense de la culture et de l'étude socio-économique du milieu paysan producteur. (Résumé d'auteur)
The quality of coffee is influenced by many factors such as coffee variety, agricultural and post... more The quality of coffee is influenced by many factors such as coffee variety, agricultural and postharvest conditions, roasting parameters, and brewing. The pleasure of drinking coffee may be affected by off-notes such as burnt, green, earthy, or fermented. Their presence is related to the variety, fermentation during postharvest processing, or over-roasting of the beans. Sensory expert panels trained for the evaluation of coffee are able to detect off-notes and select coffees by well-defined quality criteria. The application of instrumental approaches detecting quality markers related to the perceived off-notes is shown to be useful to assist sensory panels. This paper describes the discovery of a new marker compound related to the fermented off-note occasionally perceived in coffees. The application of untargeted chemometric methods on volatile compounds revealed correlations between individual compounds and the sensory attribute. The new marker compound was identified as ethyl formate, which can be measured in the headspace of roasted and ground coffee by various analytical techniques including online proton transfer reaction mass spectrometry.
In Vitro Cellular & Developmental Biology - Plant, 2007
ABSTRACT The objective was to set up a pilot scale process for robusta (Coffea canephora) industr... more ABSTRACT The objective was to set up a pilot scale process for robusta (Coffea canephora) industrial propagation by somatic embryogenesis in liquid media. A batch production of pre-germinated embryos was initiated once every 2mo. in 2003 and 2004, then every mo. in 2005. Each run batch requires 4 to 6mo. to produce the pre-germinated somatic embryos and consists of three phases: (1) the development of torpedo stage embryos in Erlenmeyer flasks, (2) pre-germination in temporary immersion bioreactors to allow maturation from the torpedo stage to the cotyledonary stage, (3) maintaining the embryos under storage conditions before their shipment to coffee producing countries. Starting from 1kg of embryogenic calluses, a total of 4.4 million pre-germinated embryos for 17 clones were produced over 3yr. This embryo number was enough to potentially regenerate 2 million plants, as the global embryo-to-plantlet conversion rate was estimated to 46% after acclimatization and complete germination in the greenhouse. At the end of April 2006, 600,000 somatic seedlings were transferred into plastic bags in nurseries or were already planted in the fields, mainly in Thailand. The current capacity allows the production of 2.5 million embryos per year, equivalent to a potential of about 1.0 million plantlets. The technical package has recently been transferred to National Institutes in Mexico, Thailand, and Vietnam.
Coffea canephora is subject to enormous competitive challenges from other crops, especially for f... more Coffea canephora is subject to enormous competitive challenges from other crops, especially for farmer sustainability and consumer requirements. Coffee breeding programs have to focus on specific traits linked to these two key targets, such as quality character, largely depending on the bean's biochemical composition and field yield. Two segregating populations A and B, from crosses between a hybrid (Congolese×Guinean) FRT58 parental clone and a Congolese FRT51 genotype and between two Congolese parents FRT67 and FRT51, respectively, were used to characterize the quantitative trait loci (QTL) involved in agronomic and biochemical traits. A consensus genetic map was established using 249 SSRs covering 1,201 cM. Three QTL detection models per population with MapQTL (model I) and MCQTL (model II) followed by a connected population approach with MCQTL (model III) were compared based on their efficiency, precision for QTL detection, and their genetic effect assessment (additive, dominance, and parental-favorable allele). The analysis detected a total of 143 QTLs, 60 of which were shared between the three models; 28 found with two models; and two, 13, and 40 specific from models I, II, and III, respectively. The last model III based on connected populations is much more efficient in detecting QTLs with low variance explained and led to the genetic characterization of favorable allele. Thanks to this comparison of three QTL detection models on our quantitative genetic study, we will give a new insight for coffee breeding programs dedicated to managing complex agronomic or qualitative traits.
The purpose of the study was to evaluate the possible genetic effect on vegetative propagation of... more The purpose of the study was to evaluate the possible genetic effect on vegetative propagation of Coffea canephora. Diversity for somatic embryogenesis (SE) ability was observed not only among two groups of C. canephora Pierre (Congolese and Guinean), but also within these different genetic groups. The results therefore showed that, under given experimental conditions, SE ability is depending on genotype. Furthermore the detection of quantitative trait loci (QTLs) controlling the SE and cutting abilities of C. canephora was performed on a large number of clones including accessions from a core collection, three parental clones and their segregating progenies. On the one hand we detected eight QTLs determining SE. Six positive QTLs for SE ability, whatever the criteria used to quantify this ability, were localized on one single chromosome region of the consensus genetic map. Two negative QTLs for SE ability (frequency of micro calli without somatic embryo) were detected on another linkage group. Deep analysis of the six QTLs detected for SE ability came to the conclusion that they can be assimilated to one single QTL explaining 8.6-12.2% of the observed variation. On the other hand, two QTLs for average length of roots and length of the longest sprouts of cuttings were detected in two linkage groups. These QTLs detected for cutting ability are explaining 12-27% of the observed variation. These observations led to conclude that SE and cutting abilities of C. canephora Pierre appeared to be genetic dependent but through independent mechanisms.
Considerable work has been devoted in the last decades to the identification and quantification o... more Considerable work has been devoted in the last decades to the identification and quantification of key aroma-active compounds in coffee as well as their precursors. The aim of this work was to demonstrate the applicability of a data-driven holistic method rather than a targeted chemical study. As an illustrative example, coffees at different roast degrees were analysed with a range of instrumental techniques (LC-MS, GC-MS, PTR-MS) and evaluated by a sensory panel. This allowed identifying correlations between chemical markers and sensory qualities and developing a deeper understanding on reaction mechanisms involved in coffee aroma formation.
Uploads
Papers by Charles Lambot