15 research outputs found
Biochemical and bioactive phytonutrients changes in tissues of two cultivars of fresh-cut cassava in stick form under refrigerated storage
The aim of this study was to evaluate the effects of fresh-cut in stick form of two cassava cultivars on their biochemical and antioxidant characteristics, at two harvest times. The fresh cut cassava sticks were packaged in polypropylene, maintained at 5±1ÂșC, with 90±5% relative humidity for 12 days. The concentration of carotenoids, total soluble phenolic compounds and the activity of phenylalanine ammonia lyase and antioxidant capacity were significantly higher for the sticks of cultivar 'Amarela' cassava than for the sticks of cultivar 'Cacau'. The concentrations of carotenoids, total soluble phenolic compounds, and the activity of phenylalanine ammonia lyase and antioxidant capacity were all significantly greater when harvested at 14-month of age. There was a significant increase in the activity of phenylalanine ammonia lyase during the 12 days of storage at 5ÂșC. However, there was a decrease in total carotenoids, soluble phenolic compounds, and in the antioxidant capacity of the two cultivars
Effets de la mycorhize à vésicules et arbuscules, de la température et du phosphore sur la fusariose de la patate douce
RĂ©union: International Society for Tropical Root Crops. Africa Branch, Triennial Symposium, 2d, 14-19 Aug. 1983, Douala, CMDans IDL-638
Effects of vesicular arbuscular mycorrhizae, temperature, and phosphorus on Fusarium wilt of sweet potato
Meeting: International Society for Tropical Root Crops. Africa Branch, Triennial Symposium, 2d, 14-19 Aug. 1983, Douala, CMIn IDL-737
Reaction of cassava genotypes to the cassava mosaic disease in three distinct agroecologies in Nigeria
Nine cassava genotypes were grown at six representative sites in Nigeria for 3âyears to study their response to cassava mosaic disease (CMD), investigate the influence of genotypeâĂâenvironment (GĂâE) interactions on their reactions to the disease, and identify genotypes with stability to the disease, using the Additive Main Effects and Multiplicative Interaction statistical model. Environments, genotypes and GâĂâE interactions were highly significant (Pâ<â0.01) for the disease. The GâĂâE interactions accounted for 19.5% of the treatment sums of squares for CMD and influenced the relative ranking of genotypes across environments. The magnitude of the GâĂâE interaction effect for CMD was larger than that of genotypes. Examination of the GâĂâE interaction structure revealed specific areas where screening of cassava genotypes for resistance to CMD could be performed best. The study identified genotypes such as TMS 30001 and 63397 with resistance to CMD and CMDâstable clone U/41044, which could be distributed to growers, and sites such as Ibadan and Ubiaja with high CMD severity for screening genotypes for reaction to CMD
The influence of host genotype X environment Interactions on the response of Cassava Anthracnose disease in diverse agro-ecologies in Nigeria
Nine cassava ( Manihot esculenta ) genotypes were grown for three
years (1992-1993, 1993-1994 and 1994-1995) in three agro-ecological
zones in Nigeria to study their reaction to cassava anthracnose disease
(CAD), caused by Colletotrichum gloeosporioides , investigate genotype
x environment (G x E) interaction patterns for their reaction to
anthracnose, and to identify genotypes with stability of resistance to
the disease. Mean squares for environments, genotypes and G x E
interactions were highly significant (P<0.0001) for anthracnose
infection. Significant G x E interactions, accounting for 19% of the
treatment sums of squares, indicated that genotypes responded
differentially to anthracnose infection across environments. The
additive main effects and multiplicative interaction (AMMI) statistical
model selected AMMI3 as the best predictor for anthracnose because it
had the smallest root mean square prediction difference (0.41), and
explained 99% of the G x E interaction for cassava anthracnose disease.
Anthracnose severity was low in all three years. Highest disease
severity was recorded in 1992-93 (2.1) and the least in 1994-95 (1.69).
Clone U/41044 was the most resistant and TME1 the most susceptible to
CAD. Clone 30555 showed the most stable reaction and TME1 the least
stability to CAD. The most disease was recorded in Ibadan and Owerri,
making them good sites for screening cassava for anthracnose
resistance.Neuf génotypes de manioc ( Manihot esculenta ) étaient
cultivĂ©s pour trois annĂ©es (1992â1993, 1993â1994
et 1994â19995) dans trois zones agro Ă©cologiques au Nigeria
en vue d'étudier leur réaction à la maladie
d'anthracnose du manioc (CAD), causée par les Colletotrichum
gloeosporioides , examiner les modĂšles d'interaction
gĂ©notype x environnement (G x E) pour leur rĂ©action Ă
l'anthracnose, et identifier les génotypes ayant une
stabilité de résistance à la maladie. Les carrées
des moyennes pour les interactions environnements, génotypes et G
x E étaient significativement élevées (P<0,0001) pour
l'infection Ă l'anthracnose. Les interactions significatives G x
E, comptant pour 19% des sommes des traitements des carrées, ont
indiqué que les génotypes ont répondu
différentiellement à l'infection d'anthracnose à travers
les environnements. Les principaux effets additifs et multiplicatifs
d'interaction (AMMI) du modÚle statistique sélectionné
AMMI3 comme le meilleur prédicteur d'anthracnose parce que ayant
la plus faible moyenne des racines carrées de différence de
prédiction (0,41), et a expliqué 99% d'interaction G x E de
maladie d'anthracnose de manioc. La sévérité
d'anthracnose était faible pendant toutes les trois années.
La plus forte sévérité de la maladie était
enregistrĂ©e en 1992â93 (2,1) et la plus faible en
1994â95 (1.69) le clone U/41044 Ă©tait le plus rĂ©sistant
et le TME1 le plus susceptible Ă la CAD. Le clone 30555 a montre
la plus stable réaction et le TME1 la plus faible à la CAD.
La plupart des maladies était enregistrée en Ibadan et
Owerri, faisant d'eux les bons sites d'étude de résistance de
manioc Ă l'anthracnose
Boilable cassava varieties: what is their role within the context of the global agricultural economy?
Cassava production and utilization in Cameroon have undergone a long evolution. The post-independenceand pre-1990 eras were marked by activities that considered cassava to be a subsistence food crop. Duringthis period, farmers relied on coffee and cocoa as the major cash crops. Cassava growers used mainly boilâandâeat varieties that could be sold in local markets.. The crop gradually became important as a cash cropwhen coffee and cocoa prices fell in the world market. In recent years, cassava has gained prominence in allparts of the country where the crop is now grown for cash. Varieties responding to this market demand havehad to be developed and disseminated to growers. The issue of the types of varieties needed to give cassavaits place in the world market needs to be revisited. Effective processing and high quality control of processedproducts have to be addressed adequately for cassava to insert itself in the global econom
Pre-planting removal of host-plant residues to reduce African root and tuber scale infestations in cassava fields in Cameroon
The African root and tuber scale (ARTS) Stictococcus vayssierei Richard is a subterranean insect originally infesting several native plant species in the forest zones of Central Africa. With help of the native ant Anoplolepis tenella Santchi, ARTS has recently emerged as a major constraint to cassava production. We conducted an experiment in 18 farmer fields in two villages in the Forest Margins Benchmark Area of Cameroon to test the hypothesis that removal from fallows of known host-plant residues prior to field establishment will reduce subsequent ARTS infestation on cassava. Two 20m x 20m plots ('treated' and control) were established in each of 18 fields. Both plots were prepared and subsequently managed by the farmer according to field practices prevalent in the area. In the 'treated' plot, however, all host-plant residues were removed thoroughly prior to cassava planting. Densities of ARTS and its associated ant were determined on a sample of ten plants in each plot at three, six and nine months after planting (MAP). Overall average ARTS density per plant was not significantly different between treated and control plots. However, variation in ARTS densities between fields within a village was high, and in several fields ARTS densities were
significantly higher in one plot compared with the other. ARTS densities were higher in control than in treated plots in 4 out of 18 fields, while higher scale densities occurred in treated compared with control plots in one field. ARTS densities did not differ between plots in the remaining 13 fields. These results indicated that removal of host-plant residues before planting as it was practiced in this study cannot significantly reduce ARTS infestations on cassava. Explanations and recommendations are provided for further testing of the impact of pre-planting host-plant residue removal on ARTS infestations in cassava fields in Central Africa