scholarly journals BREEDING OF COCOA TREES (THEOBROMA CACAO L.) RESISTANTTO PHYTOPHTHORA MEGAKARYA, AGENT OF BLACK POD DISEASE IN COTE DIVOIRE

2021 ◽  
Vol 9 (09) ◽  
pp. 793-803
Author(s):  
Boguinard Sahin Honorine Guiraud ◽  
◽  
Gnion Mathias Tahi ◽  
Klotioloma Coulibaly ◽  
Desire Pokou ◽  
...  

Backgrownd : Black pod disease is the cause of significant production losses of cocoa trees. This work aims to select tolerant and resistant genotypes to Phytoththoramegakarya within the main collection of cocoa trees of the National Center for Agronomic Research. Methods : The artificial inoculation test on leaf discs, was used in this study to assess the susceptibility of 52 clones of high-producing cocoa trees resistant in the field to black podcausing by P. megakarya. Results : Three groups of susceptibility to P. megakarya were demonstrated according to the reference controls. The first group is composed of two clones (IFC 1035 and CC 39) qualified as susceptible to black pod. These genotypes have respective sensitivity scores (NS) of 3 and 3.06 which are lower than those of the sensitive control NA32 (NS = 3.31). The second group is composed of 43 clones qualified as moderately resistant with sensitivity scores higher than 2.59 (PA150, moderately resistant control) and lower than 3.31 (NA32). The third group is composed of four clones qualified on the one hand as resistant (IFC 1041 and IFC 1027) with sensitivity scores higher than 1.73 (SCA6) and lower than 2.59 (PA 150) and on the other of very resistant to P. megakarya (NS> 1.73), with sensitivity scores greater than 1.73 Conclusion : These genotypes resistant to P. megakarya thus selected could constitute parents to be included in a variety improvement program with a view to the selection of plant material resistant to black pod disease.

2012 ◽  
Vol 10 (3) ◽  
pp. 254-257
Author(s):  
Erwin Aragon ◽  
Claudia Rivera ◽  
Helena Korpelainen ◽  
Aldo Rojas ◽  
Paula Elomaa ◽  
...  

A total of 60 farmers' cacao accessions (Theobroma cacao L.) from Nicaragua were investigated using microsatellite markers to reveal their genetic composition and to identify potentially resistant genotypes against the black pod disease caused by Phytophthora palmivora. These accessions were compared with 21 breeders' accessions maintained locally, two Criollo accessions from Costa Rica and two accessions from Ecuador. The analyses showed a low level of differentiation among groups of farmers' accessions (FST = 0.06) and that six Nicaraguan accessions were genetically closely related to the two Criollo accessions used as a reference. In addition, seven distinct genotypes were found to have allelic composition that may indicate linkage to resistance alleles, thus being potential parental lines in future breeding programmes.


2018 ◽  
Vol 54 (No. 2) ◽  
pp. 74-82
Author(s):  
Minyaka Emile ◽  
Banen Collette Vanessa Madina ◽  
Kusznierewicz Barbara ◽  
Doungous Oumar ◽  
Haouni Soungouna ◽  
...  

A new strategy to reduce the severity of black pod disease (BPD) in T. cacao plants using MgSO<sub>4</sub> nutrition was investigated. The dynamics of the tolerance to BPD of 18 susceptible T. cacao plantlets coming from the cross (♀SNK64 × ♂UPA14) was monitored during weekly (8 weeks) supply of MgSO<sub>4</sub> into the soil. Prior to MgSO<sub>4</sub> application, disease scores of the 18 plantlets (in six sets of three plantlets per set) were varying between 3.5 (susceptible) and 5 (highly susceptible). After MgSO<sub>4 </sub>application, a substantial decrease in disease scores was observed compared to the control. The percentage of disease tolerance gain of plantlets versus MgSO<sub>4</sub> supplied (0–2.96 g) presented a quasi-hyperbolic curve with asymptotic line corresponding to 60% (day 28) and 70% (day 56). Cysteine content was not significantly different between the six triplets before MgSO<sub>4 </sub>nutrition. On days 28 and 56 of MgSO<sub>4</sub> supplementation, cysteine content presented a pattern similar to the tolerance gain of plantlet sets. The monitoring of glutathione content versus MgSO<sub>4</sub> supplementation (compared to day 0) showed sigmoid (day 28) and hyperbolic (day 56) curves which were associated with defined mathematical laws determined by MALAB software. Negative and highly significant correlations were observed between disease scores, cysteine and glutathione contents in leaves while positive and highly significant correlations were observed between cysteine and glutathione contents in leaves. These data might mean that MgSO<sub>4</sub> nutrition significantly improved the tolerance of T. cacao. The mechanism of tolerance improvement might be associated with the synthesis of sulphur-containing compounds (cysteine and glutathione) which might be directly or indirectly used by T. cacao against P. megakarya.


2019 ◽  
pp. 15-20
Author(s):  
N.V. Proletova

Цель исследования заключалась в разработке эффективной селективной системы invitro для создания устойчивых к антракнозу генотипов льна. В качестве объекта исследований использованы сорта и линии льна Linum usitatissimum L., различающиеся по устойчивости к антракнозу. Штаммы гриба, включённые в исследования, различались по вирулентности. В исследованиях использовали методики Доспехова, Курчаковой, Методические рекомендации по созданию, поддержанию, хранению и практическому использованию Коллекции микроорганизмов возбудителей болезней льна. В результате разработана селективная система invitro гриб Colletotrichum lini Mannset Bolley лён, позволяющая отбирать клетки льнадолгунца invitro, устойчивые к культуральному фильтрату, из которых с большей эффективностью можно получать растениярегенеранты, устойчивые к патогену. В культуральных фильтратах исследуемых штаммов возбудителя установлено наличие аминокислот: аланин, глицин, аспарагин, цистеин, аспарагиновая и глютаминовая кислоты, аргинин, треонин. Выявлена зависимость отзывчивости клеток льна на присутствие в среде продуктов жизнедеятельности гриба возбудителя антракноза от величины экспланта. Клетки пыльников в селективных условиях были более уязвимы, чем клетки незрелых зародышей. Выявлено влияние генотипа льна на потенции клеток к морфогенезу в селективных условиях. Клетки генотипов Л 95787, Алексим, Пенджаб, Зарянка обладали высокой морфогенетической активностью. Морфогенетический потенциал генотипов Л 150684, Росинка был исчерпан уже ко 23 пассажу. При разработке схемы селекции льна invitro на устойчивость к антракнозу получено 86 побегов, проверка которых на искусственном инфекционнопровокационном фоне показала, что генотипы различались по устойчивости. Наряду с устойчивыми и среднеустойчивыми к антракнозу линиями (на уровне 5075) были и формы, восприимчивые к болезни. У устойчивых и среднеустойчивых генотипов параметры устойчивости были на 1237 выше, чем у исходных форм.The purpose of the research was to develop an effective selective system invitro for the creation of flax genotypes resistant to anthracnose. Flax varieties and lines of Linum usitatissimum L. differing in resistance to anthracnose were used as the object of research. The fungal strains included in the researches differed in virulence. Dospekhov and Kurchakovas methods, Methodical recommendations on the creation, maintenance, storage and practical use of the Collection of microorganisms of flax pathogens were used in the researches. As a result, a selective invitro system called Fungal Colletotrichum lini Mannset Bolleyflax has been developed which allows the selection of cells of longstalked flax invitro resistant to culture filtrate from which pathogenresistant regenerants can be obtained with greater efficiency. In the culture filtrates of the studied pathogen strains the presence of amino acids is established: alanine, glycine, asparagine, cysteine, aspartic and glutamic acid, arginine, threonine. The dependence of the responsiveness of flax cells to the presence in the environment of waste products of the fungus, the causative agent of anthracnose, on the size of the explant was revealed. Anther cells under selective conditions were more vulnerable than cells of immature germs. The influence of flax genotype on cell potency to morphogenesis in selective conditions has been revealed. Cells of genotypes L 95787, Alexim, Penjab, Zaryanka possessed high morphogenetic activity. The morphogenetic potential of genotypes L 150684, Rosinka was exhausted already by passage 23. When developing a plan for the selection of flax invitro for resistance to anthracnose 86 shoots were obtained, checking them on an artificial infectiousprovocative background showed that the genotypes differed in resistance. Along with resistant and moderately resistant to anthracnose lines (at a level of 5075), there were also forms susceptible to the disease. In resistant and moderately resistant genotypes, resistance parameters were 1237 higher than in the original forms.


2016 ◽  
Vol 46 (4) ◽  
pp. 429-433
Author(s):  
Renato Carrer Filho ◽  
◽  
Renata Maria Oliveira ◽  
Vanessa Duarte Dias ◽  
Geisiane Alves Rocha ◽  
...  

ABSTRACT Vascular wilting in tomato plants is an important disease caused by soil-inhabiting pathogens, especially Verticillium dahliae, which results in significant production losses. Control measures against this disease are difficult to implement due to intrinsic pathogen characteristics, such as high adaptability to the subterranean environment, in association with the host, and development of resistance structures that remain viable in the soil for long periods. The introgression of genes that express resistance is the main control measure and requires a continuous characterization program of resistant accessions. This study aimed at identifying tomato (Solanum lycopersicum) accessions resistant to V. dahlia, by using the phenotypic and genotypic methods. The reaction of 33 tomato accessions to different V. dahliae isolates was reinforced by molecular analysis, through markers linked to Ve resistance genes. The combination of bioassays and specific molecular markers showed a high correlation (94.3 %), with the selection of 25 accessions resistant to V. dahliae.


2012 ◽  
Vol 7 (2) ◽  
pp. 39-54 ◽  
Author(s):  
D. Nyadanu ◽  
R. Akromah ◽  
B. Adomako ◽  
C. Kwoseh ◽  
S.T. Lowor ◽  
...  

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