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±1ºC, 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 5ºC. 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

Réunion: 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 3 years to study their response to cassava mosaic disease (CMD), investigate the influence of genotype × environment (G× E) 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 G × E interactions were highly significant (P < 0.01) for the disease. The G × E 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 G × E interaction effect for CMD was larger than that of genotypes. Examination of the G × E 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 CMD‐stable 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 cultivés pour trois années (1992–1993, 1993–1994 et 1994–19995) dans trois zones agro écologiques au Nigeria en vue d&apos;étudier leur réaction à la maladie d&apos;anthracnose du manioc (CAD), causée par les Colletotrichum gloeosporioides , examiner les modèles d&apos;interaction génotype x environnement (G x E) pour leur réaction à l&apos;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&apos;infection à l&apos;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&apos;infection d&apos;anthracnose à travers les environnements. Les principaux effets additifs et multiplicatifs d&apos;interaction (AMMI) du modèle statistique sélectionné AMMI3 comme le meilleur prédicteur d&apos;anthracnose parce que ayant la plus faible moyenne des racines carrées de différence de prédiction (0,41), et a expliqué 99% d&apos;interaction G x E de maladie d&apos;anthracnose de manioc. La sévérité d&apos;anthracnose était faible pendant toutes les trois années. La plus forte sévérité de la maladie était enregistrée en 1992–93 (2,1) et la plus faible en 1994–95 (1.69) le clone U/41044 était le plus résistant et le TME1 le plus susceptible à 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&apos;eux les bons sites d&apos;étude de résistance de manioc à l&apos;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 boil–and–eat 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