Institute Of Agricultural Research For Development Research Articles

Factors affecting lactation performances of Jersey-White Fulani and Holstein-Gudali genetic crossed groups of cows in Western Highlands of Cameroon

The aim of this study was to evaluate factors affecting daily milk yield, lactation peak milk and calving interval lactation peak of Jersey-White Fulani and Holstein-Gudali genetic crossed groups of cows in Western Highlands of Cameroon. Data on 404 genetic crossed cows obtained from the database of the Institute of Agricultural Research for Development (IRAD) of Bambui in the Western Highlands of Cameroon were used. These genetic crossed cows were results of crosses between imported Jersey (J) and Holstein (H) bull semen with local White Fulani (WF) and Gudali (G) cows. Results obtained revealed that only daily milk yield (DMY) varied significantly between the different genetic crossed groups of cows. Daily milk yield, lactation peak milk (LPM) and calving interval lactation peak (CILP) tended to increase with exotic blood level. Cows with 70% of Holstein exotic blood (75%Hx25%G) recorded the highest LPM (14.51 ± 2.97 kg) and the longest CILP (39.86 ± 9.89 days) being the highest DMY (6.74 ± 0.41kg) was in 50%Hx50%G genetic crossed group. Genetic crossed group II (75%Jx25%WF) registered the lowest DMY (5.59 ± 0.43 kg) and the lowest LPM (10.46 ± 1.16 kg) meanwhile the shortest CILP (27.19 ± 3.68 days) was obtained with genetic crossed group I (50%Jx50%WF). Performances obtained for both DMY, LPM and CILP with Holstein-Gudali (50%Hx50%G and 75%Hx25%G) crossed as compared to Jersey-White Fulani crossed revealed their high productive potential through their adaptability capacity to harsh conditions of tropics.

Combined Effect of Doses of Fertilizer and Different Densities on Agronomic Parameters of Rice (Oryza sativa (L.)) Adapted in Humid Area in The Valley of Benoué, Cameroon

The study was conducted on July 2021, at the Institute of Agricultural Research for Development (IRAD). The main objective of the study was to determine the dose of mineral fertilizers and densities which respond well to the rice culture, variety Nerica L36 in a humid area of the valley of Benoué. Fertilizers doses were: T1 (0 kg NPKSB+100 Kg Urea/ha); T2 (150 kg NPKSB+100 Kg Urea/ha); T3 (200 kg NPKSB+100 Kg Urea/ha; T4 (250 kg NPKSB+100 Kg Urea/ha). Three densities were considered: De1= 20 cm x 20 cm; De2= 25cm x 25cm; De3= 30 cm x 30 cm. The experimental design was a split-plot, with two factors in three replications: Factor 1 concerning fertilizers doses and Factor 2 relating to densities. Evaluation parameters were: the height of plant, the number of tillers, the number of panicle/plants, length of panicles, heading date at 80 % and maturity date. Harvest data collected were: the number of grains/panicles, weight of 1000 grains, potential yields. The results showed that the effect of different amounts especially doses 2, 3 and 4 were highly significant (P≤0.05) in influencing the height of plant, number of tillers, number of panicles/plants, length of panicles for all densities. These densities were considered suitable for growing aspect of rice. On the other hand, the densities 1 and 2 were suitable for the element of heading date at 80 % for the doses 1 and 2, maturity date with dose 1. However, yield aspects were most significant (P≤0.05) with the dose 2, 3 and 4 on a number of grains/panicles and potential yield especially, which permit us to deduce that densities 1, 2 and 3 were suitable for these yield parameters

Antifungal Potential of Acetone and Ethyl Acetate Extracts of Thevetia peruviana on Development of Phytophthora colocasiae, Causal Agent of Late Blight of Taro (Colocasia esculenta (L.) Schott) from Three Agro-Ecological Zones of Cameroon

Aims: This study was aimed to evaluate the antifungal activities of acetone and ethyl acetate extracts of Thevetia peruviana seeds on the in vitro growth of the fungus.
 Study Design: A randomized sample block design containing four treatments (T- = Negative control; T2= Ethyl acetate extract; T3= Acetone extract; T+=Callomil Plus) with three repetitions was used. Plant extracts were used at three concentrations: C1: 12.5 µl/ml; C2: 25 µl/ml and C3: 50 µl/ml; the chemical fungicide at the dose of 12.5 μL/ml.
 Place and Duration of Study: The study was conducted in the University of Yaoundé 1, Faculty of Sciences, Department of Plant Biology, Laboratory of Phytopathology and Crop Protection, and in the Institute of Agricultural Research for Development (IARD) of Yaoundé, Laboratory of Phytopathology, during the year 2019-2020.
 Methodology: acetone and ethyl acetate extracts of T. peruviana were prepared and used at concentrations of 12.5, 25 and 50 µl/ml. P. colocasiae was isolated from infected taro leaf cultivars "Macumba or Ibo coco" located in three different regions: west, Littoral and Centre. The various explants were were put in V8 agar medium and maintained in pure culture. Mycelial fragments of P. colocasiae of about 0.8 cm in diameter were cut and placed in sterile Petri dishes containing Potato Dextrose Agar (PDA) medium supplemented with different concentrations of plant extracts and incubated at 23±1°C for seven days for the evaluation of the radial growth.
 Results: The results obtained showed that the acetone and ethyl acetate extracts have completely inhibited the growth of the strain of West at 25 μ/ml while total inhibition of the pathogen was not obtained with strain of Centre region. The lowest inhibition was obtained with the strain of Littoral region: 93.88 % for acetone extract and 90.78 % for ethyl acetate extract compare to 100 % for west and Centre region at highest concentration.
 Conclusion: The acetone and ethyl acetate extracts at the concentration of 25 μ/ml totally inhibited the in vitro radial growth of some strains of P. colocasiae. These extracts, which are effective against P. colocasiae, may substitute fungicides in the fight against taro leaf blight.

Effect of Microbial Inoculant on Physicochemical and Microbiological Properties of Cassava Fermentation Process and Fufu Produced

Aim: The effects of adding a microbiological inoculant on the physicochemical and microbiological properties during the fermentation process of cassava (Manihot esculenta Crantz) and on the sensory characteristics of the fufu produced using a local Bambili cassava variety were examined.
 Study Design: Completely Randomized Design was applied for this study.
 Place and Duration of Study: Study was carried out at the Food Technology and Post-Harvest Programme Laboratory (FTPHL) of the Institute of Agricultural Research for Development (IRAD) Bambui, North West Region of Cameroon, between January and April 2020.
 Methodology: Cassava was soaked in water and three treatments: 0%, 1% and 4% Light Matrix Organics (LMO) added to the water. The fixed submerged fermentation was used. Water samples were randomly collected daily and analysed for pH, temperature, Titratable Acidity (TA) and microbial counts. The experiment was carried out in triplicates, varying temperature each time (35oC in trial 1, 32oC in trial 2 and 21oC in trial 3). Sensory evaluation was carried out on the fufu produced.
 Results: Temperature, pH, TA and microbial counts followed the same trend in all 3 treatments. TA increased from 0.01-0.15%, while pH decreased from 6.9-4.85. Temperature increased then dropped at the end of the experiment. Total bacterial counts increased from log10 (3.49) to log10 (6.9) CFUml-1. Yeasts and moulds increased from log10 (7.15) CFUml-1 and then dropped to log10 (5.48) CFUml-1 at the end of the experiment. Coliforms decreased from log10 (4.66) CFUml-1 to log10 (3.30) CFUml-1. The above parameters did not vary significantly (p<0.05) within treatments. Also, soaking temperature affected the duration of fermentation, hence the finished product. The natural fermentation process was preferred for colour, taste and flavour while the 1% LMO sample was preferred for texture.
 Conclusion: Under good hygienic conditions; water fufu produced by natural fermentation will be of good quality for consumption.

Development of a Technical Itinerary for the Production of Avocado (<i>Persea américana</i> Mill.) Seedlings with Biofertilizers

The cultivation of fruit trees generally requires a nursery phase during which the young seedlings are monitored and treated to improve their ability to adapt to the environment. This leads to the production of seedlings that are used to create orchards. It consists of four essential steps or operations: 1) The germination phase of the seeds in germinators for the production of rootstocks; 2) Transplanting into pots or bags; 3) Fertilisation in order to obtain seedlings of a satisfactory vigour (stem diameter) ready for grafting. The nursery phase requires a good understanding and mastery of plant regeneration and fertilisation techniques. In Cameroon, the demand for avocado (Persea americana) fruits is increasing, but the supply is not keeping up with this demand. After a summary monograph on the production practices of avocado seedlings in the Yaounde area, this work aims to optimise the aforementioned three steps in order to obtain seedlings of sufficient sizes for grafting. Three factors are considered in this study: 1) The substrate (Substrate), whose effects are evaluated by the germination rate (GR), the daily average germination (DAG) and the root volume of seedlings (RootV). 2) The transplanting date (TransD), determined by considering three dates including 40 (Trans40), 65 (Trans65) and 75 (Trans75) days after sowing, and 3) Fertilisation using biological fertilisers, evaluated by testing four fertilisation levels, Fert1 (10 gr of 20-10-10 plus 10 gr fowl droppings), Fert2 (Acaulospora tuberculata), Fert3 (Gigaspora margarita) and Fert4 (Mixed mycorrhizal strains of Gigaspora margarita and Acaulospora tuberculata). This third factor is evaluated by growth parameters including leaf area (LeafA), chlorophyll index (ChlorInd), gain in Plant height (GainPltH) and plant diameter (GainPltD). The trial took place in the First Seed company, a seed production unit located in the Simbock district of Yaounde for the field phase, and the Biological Control Laboratory of the Institute of Agricultural Research for Development (IRAD), Nlolbisson, Yaounde. Two trials were conducted, the first with the objective of determining the best substrate with a completely randomized block design in 2 replications, three substrates/replication. The second trial was done with a factorial design (Split plot) with three replicates, the main factor being the Transplanting Date (TransD) and the second factor the biological fertilizer. Data were separated using least significant difference at 5% treshhold. Results indicate a highly significant effect of substrate on RootV (p = 5.00E-03). This effect translated by an increase of 49.42% and 19.53% of root volume on sawdust respectively to sand and soil. Sawdust (100%) and soil (98%) affect germination by 8 days reduction over sand and the germination rate on these two substrates is higher than the one on sand (92%). The early transplanting (TransD40) allows a better growth of the seedlings in terms of stem length and the collar diameter. The only observation variable that stands out for the early nursery stage fertilisation is leaf area, which shows significant differences between the 4 fertilisation formulae tested. The chlorophyll index and leaf area are also strongly correlated with the seedling growth parameters. Our results show that the early transplanting stage (40 days after planting) combined with a germination on white sawdust should be proposed to reduce the production cycle of grafted seedlings in association with early application of biofertilisers or organic fertilizer.

Analysis of leaf phenotypic diversity of some Hevea Accessions/clones conserved at the Institute of Agricultural Research for Development (IRAD) Ekona, Cameroon

This study was carried out to estimate leaf morphological diversity of some accessions/clones from IRRDB 1981 Hevea germplasm collection conserved at IRAD Ekona, to determine the importance of leaf morphological descriptors in differentiating accessions/clones. A total of 36 clones/ accessions were characterized using 6 leaf morphological descriptors. Analysis of variance showed that there were significant differences in the leaf morphological parameters for the studied clones. The Principal Component Analysis (PCA) showed that all leaf descriptors were informative and contributed significantly to the variation. The first 2 Principal Component scores (PCs) accounted for 88% of the total variation. The cluster analysis based on significant PCs grouped all accessions and clones in to 6 main clusters at the distance of 1.5. This study permits the characterization of Hevea accessions and clones in to diverse groups using leaf morphological descriptors; hence this will be advantageous for production of diverse genotypes during breeding programs to broaden the Hevea gene pool.

Analysis of leaf phenotypic diversity of some Hevea Accessions/clones conserved at the Institute of Agricultural Research for Development (IRAD) Ekona, Cameroon

Analysis of leaf phenotypic diversity of some Hevea Accessions/clones conserved at the Institute of Agricultural Research for Development (IRAD) Ekona, Cameroon

Profitability and Impact of Inorganic Fertilizers on the Maize Production in Ekona, Cameroon

Summary Declining soil fertility and low fertilizer use are the major abiotic factors limiting the maize production in Cameroon. Therefore, the design and introduction of appropriate fertilizer schemes, which would improve maize yields and provide incentives for smallholder farmers, are considered imperative. In 2018, a field experiment was conducted on the farm of the Institute of Agricultural Research for Development (IRAD) in Ekona, the south-west region of Cameroon, to investigate the profitability and impact of inorganic fertilizers on maize production. The experiment was laid out in a randomized complete block design with four replications and four treatments, using different fertilizer rates per hectare in each treatment (namely unfertilized control (T1), 50 kg urea + 50 kg N-P-K (T2), 100 kg urea + 100 kg N-P-K (T3) and 150 kg urea + 150 kg N-P-K (T4)). The results obtained indicate that all the maize growth parameters (plant height, number of leaves per plant, stem girth and leaf area) and yield components considered (cob length, cob diameter and test weight of 100 grains) were significantly (P < 0.05) higher in T4 than T1. The grain yields recorded ranged from 4.09–5.88 t ha−1 and were also statistically (P < 0.05) higher in T4 than T1. The incremental income based on the fertilizer use was the highest in T4, followed by T3 and T2. The value cost ratio (VCR) was greater than 2 in all the treatments and was found to be highest in T2 (3.15), followed by T4 (2.52) and T3 (2.49). As T2, T3 and T4 did not differ statistically (P > 0.05), all the fertilizer rates considered were economically viable, but T4 provide the most cost-effective due to its higher grain yields and incremental income.

Efficacy of Methanolic and Aqueous Extracts of Thevetia peruviana (pers.) K. Schum on Growth of Phytophthora colocasiae Racib, Causal Agent of Taro Late Blight in Cameroon

This study aims to evaluate the antifungal activities of methanolic and aqueous extracts of Thevetia peruviana seeds on the in vitro growth of Phytophthora colocasiae. A randomized sample block design containing four treatments (T-: absolute control, AE, ME and Callomil Plus at the dose of 12.5 μL/ml) with three repetitions was used. Plant extracts were used at three concentrations: C1: 12.5 µl/ml; C2: 25 µl/ml and C3: 50 µl/ml. The study took place in the University of Yaoundé 1, Faculty of Sciences, Department of Plant Biology, Laboratory of Phytopathology and Crop Protection, and in the Institute of Agricultural Research for Development (IARD) of Yaoundé, Laboratory of Phytopathology, during the year 2019-2020.
 Aqueous and methanolic extracts of T. peruviana were prepared and used at the concentrations of 12.5, 25 and 50 μL/ml. P. colocasiae was isolated from infected taro leaf cultivars "Macumba/Ibo coco" located in three different regions in Cameroon: West, Littoral and Centre. The different leaf explants of taro were put in V8 agar medium and maintained in pure culture. Mycelial fragments of P. colocasiae of about 0.8 cm in diameter were cut and placed in sterile Petri dishes containing Potato Dextrose Agar (PDA) medium supplemented with different concentrations of plant extracts and incubated at 23±1°C for seven days for the evaluation of the radial growth. Methanolic and aqueous extracts have completely inhibited the growth of West and Littoral strains at 25 μL/mL while total inhibition of the pathogen was not obtained with strain of Centre region. The lowest inhibition was obtained with the strain of Centre region (85.1%) for aqueous extract and (70.95%) for methanolic extract compare to 100% for West and Littoral region at highest concentration. The aqueous extract at the concentration of 25 μL/ml totally inhibited the in vitro radial growth of some strains of P. colocasiae. This extract, active against P. colocasiae could be used as alternative to fungicides for the control of taro leaf blight. In other hand, the strain of Littoral region was most sensible to extracts than the others. This strain could be used to provide a genetic resource for future trials in natural conditions in greenhouse and in the field.

Effect of Plant Spacing on the Growth and Yield of Rainfed Rice (Oryza Sativa) in the Bimodal Rain Forest Zone of Cameroon

A study was carried out on plant density at the experimental field of the Institute of Agricultural Research for Development (IRAD) Nkolbisson, Yaoundé to determine the appropriate spacing to improve rainfed rice production in the bimodal rainfall forest zone of Cameroon. The experiment was conducted during the main cropping seasons of 2017 and 2018. The planting spacing used were 15cm x 15cm, 20cm x 20cm, 25cm x 25cm and 30cm x 30cm giving the plant populations of 444444, 250000, 160,000 and 111,111 plants / ha respectively using two varieties (Nerica 3 and Nerica 8). The experiment was laid out in a randomized complete block design with three replications. Significant differences were observed in the growth and yield across the years. Treatments were highly significant concerning the number of days to the appearance of the first flower, the number of days to 50% flowering, and the number of days to 50 % maturity. Plants were taller with more tillers and gave higher yields in 2017 than those of 2018. The spacing significantly affected the plant height, number of tillers, and panicle length for both varieties. The interaction of spacing and variety was significant for the number of tillers per m2 and the number of seeds per panicle, however, it was not for the weight of 1000 grains and the percentage of full bales. The yield components determining yield increase were the number of panicles / m2 and the number of seeds/panicles. Nerica 3 variety gave higher yields compared to the Nerica 8, the closer the spacing, the higher the yield. There were a strong significance and positive correlation between yield, number of panicles, and the number of grain per panicle. The spacing that gives the highest number of panicle per m2 was 15 cm X 15 cm and this spacing gave good yield in the region where the study was carried out.

GESTATION LENGTH AND AGE AT FIRST CALVING OF CROSSBRED COWS IN CAMEROON

Data on 139 crossbred cows obtained from the database of the Bambui Centre of the Institute of Agricultural Research for Development (IRAD) in the Sudano-Guinean altitude zone of West Cameroon were used to evaluate the effect of calf’s sex, parity and season on gestation length and age at first calving. These animals, reared between 1985 and 1995, were crosses between the imported Jersey (J) and Holstein (H) bull semen with local White Fulani (WF) and Gudali (G) cows. Gestation length (GL) varied significantly between the different genetic crossbred groups, whereas no effect of genetic composition was observed on AFC. These traits were affected by the lactation number, but not by calf sex and season. 50%Hx50%G recorded the shortest GL (279.87±2.66 days) with 40% of cows calving between 24-28 months. 87.5%Jx12.5%WF registered the longest (289.14±3.89 days) gestation period. The highest (30.63±8.21 months) age at first calving was in75%Jx25%WF group. Performances obtained for both GL and AFC with Holstein-Gudali (50%Hx50%G) crossbreed as compared to Jersey crossbreed revealed their high reproductive potential through their adaptability capacity to harsh conditions of tropics.

Determining Appropriate Fertilizer Scheme for Maize and Sorghum Cultivation in the Sahel Agroecological Zone of Cameroon

The objective of this study was to investigate appropriate fertilization schemes to improve the production of maize and sorghum in the Sahel agroecological zone of Cameroon. The experiment was carried out in 2018 at IRAD (Institute of Agricultural Research for Development) Kismatari experimental field. The experimental setup was a complete randomized block design in four replicates and four treatments for each crop. For maize, treatments were: T1 (No input), T2 (100 kg NPK + 100 kg Urea.ha-1), T3 (150 kg NPK + 150 kg Urea.ha-1), and T4 (200 kg NPK + 200 kg Urea.ha-1). For sorghum, treatments were: T1 (No input), T2 (50 kg NPK + 50 kg Urea.ha-1), T3 (100 kg NPK + 100 kg Urea.ha-1), and T4 (150 kg NPK + 150 kg Urea.ha-1). All fertilizer treatments NPK and urea were applied to both crops respectively at 3 and 5 weeks after sowing. Nine weeks after sowing, the plant height was highest at T3, following by T2 and T4 for the two crops. The treatment T1 exhibited the lowest grain yield while T2 and T3 showed intermediate grain yield. The treatment T4 produced the highest biomass, number of ears.plant-1, and grain yield (maize: 3.3 t. ha-1, sorghum: 2.9 t.ha-1) for the two crops and thus appears to be the most appropriate fertilizer recommendation for maize and sorghum production in the Sahel zone. However, costs-benefits studies for the use of fertilizer NPK and urea are warranted to facilitate adoption by farmers in the agroecological zone.

English

The objective of this study was to test for appropriate quantity of fertilizer (NPK 12-11-18) required to boost the production of cassava (variety TME 419) in the forest zone of Cameroon. The trial was conducted at the experimental farm of the Institute of Agricultural Research for Development (IRAD) in Mbalmayo. The experimental design was completely randomized block design in three replicates. The treatments were as follows: T0 (Control (No input)); T1 (200 kg.ha-1); T2 (300 kg.ha-1); and T3 (400 kgha-1). The data were analyzed using the IBM SPSS Statistics 20 Software. The results showed that chemical fertilizer improves the growth (number of leaves, plant height, and petiole length) and yield (number of marketable root, yield) of cassava mainly because it enhances soil nutrient availability. Thus, NPK-fertilizer significantly (p<0.001) increased petiole length by 20.71, 27.83, and 31.62% for T1, T2, and T3, respectively at 5 months after planting (MAP). The highest plant height and number of leaves at 4 and 5 MAP was observed with T3 followed by T2 and T1. Similarly, the highest root yield (43.33±10.97 t.ha-1) was observed with treatment T3. Hence, the fertilizer application rate of 400 kgha-1 of NPK 12-11-18 appears most appropriate for intensification of cassava production in the humid forest agro ecological zone of Cameroon. Key words: Cassava, growth, NPK, root yield, soil fertility. &nbsp

Comparative Effect of Biological Fixation of Nitrogen and Chemical Fertilizer on Yield Optimization of Two Sorghum Varieties in the Western Highlands

Sorghum (Sorghum bicolor (L) Moench) is a staple food in Africa, South Asia and Central America. In Cameroon, it is the main food of the population of the Sudano-Sahelian zone. Its production could decline by up to 20% by the middle of the century, due to climatic disturbances. This climatic disturbance in Cameroon has led to several consequences among which, low crop yields. The comparative effect of the biological fixation of nitrogen and chemical fertilizer on the optimization of yield of two varieties of Sorghum, was conducted from July to October at IRAD (Institute of Agricultural Research for Development) station of Foumbot. The experimental design was a complete randomized block with two factors: varieties of sorghum (V1: S35 and V2: BIOGLOR) and treatments (T0: Control, T1: 20-10-10 and T2: Sorghum / NITU beans). The collar diameter, the number of leaves and plant height were evaluated each week and yield in the end of the cropping season. As a result, treatment T1 induced very significantly (P ˂ .01) growth (shoot length, leaf and collar diameter). T1 (V1: 1.30 ± 0.11 t.ha-1, V2: 2.01 ± 0.07 t.ha-1) and T2 (V1: 1.12 ± 0.02 t.ha-1, V2: 2.15 ± 0.03 t.ha-1) showed statistically equal yields, and significantly different from T0 (V1: 0.50 ± 0.06 t.ha-1, V2: 0.55 ± 0.05 t.ha-1). The BIOGLOR variety had the highest yield (1.57 ± 0.57 t.ha-1) compared to the S35 variety (0.97 ± 0.19 t.ha-1). The treatment T2 is the recommended fertilizer system because of the higher grain yield of sorghum and its ability to protect the environment.

Enhancing Micro-propagation of Some Cameroonian Plantain (Musa paradisiaca L) Cultivars/Landraces

Aims: This study was conducted to enhance germplasm conservation of some indigenous plantain landraces through tissue culture techniques in Cameroon.
 Study Design: The experiment was laid out in a completely randomized design (CRD) with three treatments in four replications.
 Place and Duration of Study: The study was conducted in the tissue culture laboratory of the Institute of Agricultural Research for Development (IRAD), Bambui, Cameroon, in the first half of 2018.
 Methodology: Explants were gotten from three plantain land races (Kwah, Ngumbe and Sangmoh) gotten from Bambui. Shoot tips were excised and cultured on Murashige and Skoog (MS) medium supplemented with 30 g of sucrose, 5 ml of ascorbic acid, 4 ml of 6- benzylaminopurine (BAP 1 mg/l), 1 ml indole-3- acetic acid (IAA 1 mg/l) and 6 g of agar at pH of 5.8±0.1 for shoot initiation and proliferation. Data was collected over a period of 12 weeks every 4th week on the average number of buds, shoot length, number of leaves, number contaminated and number dead.
 Results: All the landraces responded positively to shoot tip culture, since they could adapt and regenerate by producing buds with Ngumbe giving the highest mean number (7.0) of buds and Sangmoh giving the lowest (3.0). Analysis of variance revealed significant differences (p = 0.05) in most of the parameters measured except for number contaminated. High dead rate was recorded in Kwah with dead mean of 3.0. Ngumbe was found to regenerate better than Kwah and Sangmoh.
 Conclusion: It is recommended that the three plantain landraces, germplasm be conserved. The ramification of this finding vis-à-vis germplasm conservation and increase productivity is explained.

English

The need of characterization of local ecotypes has emerged because of abandonment of traditional varieties and a loss of genetic resources, associated with increasing demography and environmental. Thus, a study was conducted at the Institute of Agricultural Research for Development (IRAD) of Njombé multipurpose station with the objective of characterizing ten local accessions of cassava both morphologically and qualitatively. The work was carried out on two plots following the device Block Full Randomized with 3 repetitions. The yield parameters of leaves, stems, tuberous roots and dry matter of cassava were analysed using analysis of variance (ANOVA) and Duncan test mean separation at 5% using R 3.3.1 software. The evaluation of the cyanogenic potential was made following the method of Picrate Test. During the process of processing into cassava chips, tuberous roots were peeled, washed, cut with a knife, dried in the sun for three days, then packaged in plastic bags and stored as chips. As a result of this analysis, there was a highly significant difference (P Ë‚ 5%) in accessions for yield parameters in leaves, stems, tuberous roots and dry matter content. Accession 68 had an excellent yield of leaves (4.08 t/ha), stems (16.91 t/ha), and tuberous roots (8.95 t/ha). The accession 66 had excellent matter content (40%). From the morphological characterization, it appears that the accessions are all different, even if similarities were observed. The evaluation of the cyanogenic potential revealed that the accessions were low in cyanide content. In view of the conversion into cassava chips, accession 46 with the high percentage (39.20%) of obtaining the chips would be the one to be popularized for the best yield in chips. Key words: Characterization, morphology, quality, processing, cassava accession, chips. &nbsp

Growth and Yield Response of Maize (Zea mays L.) To Different Weed Control Methods in the Western Highlands of Cameroon

Weed control is an important agronomic practice that improves growth and maximizes yield in maize. An experiment was carried out to investigate the ‘effect of different weed control methods on the growth and yield of maize (Zea mays L.) in the western highlands of Cameroon. The work was carried out during the 2017/2018 main cropping season from the 14th of March to the 14th of July at the Institute of Agricultural Research for Development (IRAD) Bambui experimental field. The experiment was laid out in a Randomized Complete Block Design (RCBD) and replicated three times. The experiment comprised of seven treatments: weedy check or control (T1), constant hand hoeing (T2), delay hand hoeing (T3), pre-emergence herbicide application of Atrazine 90 DF ( 0.9 kg ha-1) (T4), post-emergence herbicide application of Ultramais 100 SC (1.9 litre ha-1) (T5), pre- herbicide application of Atrazine 90 DF ( 0.9 kg ha-1) + Ultramais 100 SC (1.9 litre ha-1) (T6) and delay post-emergence herbicide application of Ultramais 100 SC (1.9 litre ha-1) (T7). The white maize variety CHC 201 (“KASAI”) was used during the experiment and sown in plot sizes of 4 m x 5 m with a planting density of 80cm by 50cm with 2 plants per station with the aim of achieving a plant population of 50,000 plants ha-1. All agronomic practices were followed from planting to harvesting. The data recorded were plant height, number of green leaves per plant, leaf area, stem girth, days to 50% tasseling, days to 50% silking, ear height, ear length, ear girth, number of gain rows per ear, number of gains per ear, 1000 grain weight and grain yield.. The data collected were analyzed with the aid of STATGRAPHICS Plus 5.0 Software and ANOVA was run to find the differences between the various treatments. The highest 1000 grain weight (314.13g) came from the pre-emergence plus post-emergence herbicide application treatment and did not differ significantly (P˃0.05) from the constant hand hoeing treatment (307.83g). The lowest 1000 grain weight (234.67g) was seen in the weedy check treatment. The constant hand hoeing had the highest grain yield (6.27 ton ha-1) and this did not differ significantly (P˃0.05) from the pre-emergence plus post-emergence herbicide application treatment (6.07 ton ha-1). The lowest grain yield (3.18 ton ha-1) was seen in the weedy check treatment. From the study, the pre-emergence plus post-emergence herbicide application may be recommended for increasing maize yield particularly in the case of high scale production.

Growth and Yield response of Maize (Zea mays L.) to Different Rates of NPK fertilizer and Poultry manure in the Western Highlands of Cameroon

Low soil fertility is one of the factors hindering crop production in Cameroon. This is attributed to the fact that continuous cropping is carried out without adequate external farm inputs. The adoption of an Integrated Soil Fertility Management (ISFM)technique such as the combination of organic manure and chemical fertilizers is being taken as one of the solutions tothis problem. A study was conducted during the main cropping season in the experimental farm of the Institute of AgriculturalResearch for Development (IRAD), Bambui in the Western Highlands of Cameroon to investigate the effect of different rates ofNPK fertilizer and poultry manure on the growth and yield of maize (Zea mays L.). The field was laid out in a randomizedcomplete block design with tree replications and twelve treatments which were: no input (control), 300KgNPK/ha + 0Kg PM(Poultry manure)/ha, 150KgNPK/ha + 0Kg PM/ha, 0KgNPK/ha + 2.5tons PM/ha, 0KgNPK/ha + 5tons PM/ha, 0KgNPK/ha+10tonsPM/ha,150KgNPK/ha+2.5tonsPM/ha,150KgNPK/ha+5tonsPM/ha,150KgNPK/ha+10tonsPM/ha, 180KgNPK/ha + 2.5tonsPM/ha,180KgNPK/ha+5tons PM/ha and180KgNPK/ha + 10tons PM/ha. Each plot measured 4m x 5m. Planting was done at a spacing of 80cm x 50cm with two seeds per station to maintain a plant population of 50,000 plants per hectare. All cultural practices were followed from planting to harvesting. The data collected were plant height, number of leaves per plant, stem girth, leaf area, Ear length, Ear girth, number of grain rows per ear, number of grains per ear, weight of 1000 grains, and grain yield. The analysis of variance (ANOVA) was run to find the differences between the various parameters and the LSD Fisher’s multiple range test was executed to compare the different treatments. The results of the study showed that application of 0kgNPK/ha + 10tonsPM/ha and 0kgNPK/ha + 5tons PM/ha significantly (P<0.05) increased the growth and yield of maize as compared to the other treatments. The application rate of 300kgNPK/ha + 0kg PM/ha also enhanced the growth and yield of maize. Besides that, the treatment 150KgNPK/ha + 2.5tons PM/ha also gave higher yields. This later treatment may be recommended to maize producers in the study area to improve maize yields since it is more economical in terms of cost of production.

Germination rates of frozen grain legume seeds in Cameroon: Poster

A project on collection and conservation of genetic resources was carried out in Cameroon in 2014 in villages around Yaounde, Mbalmayo, and Ebolowa. Samples of all grain legume species cultivated by the farmers were collected from the 15th of March till early May 2015. Farmers in these zones cultivate mostly ground nuts, followed by soybean and cowpea. A total of 39, 13, and 45 samples were collected from Yaounde, Mbalmayo, and Ebolowa, respectively. After collection, samples were sun-dried, treated, labeled, plasticized, and stored in the freezer at -20oC in the Institute of Agricultural Research for Development (IRAD) store room at Nkolbisson, Yaounde. A trial was carried out at IRAD Kumba experimental farms in 2016 to purify and maintain 14 cowpea and 12 groundnut samples from the freezer, under the C2D project. There were highly significant differences (P< 0.05) amongst samples (treatments) for the germination rate. Cowpea samples had a germination rate ranging from 0.33 to 47.67%, while germination rates for groundnuts were between16.67 to 68.33%. Out of the 26 samples, only 5 (19%) had germination rates above 50%. Due to irregular power supply, freezing turned out to be an ineffective storage method for grain legume seeds. Seeds are now being maintained in vivo in small quantities and on seasonal basis which renders the job of plants breeders very difficult and ineffective. Alternatives storage methods and facilities for grains and seeds in developing countries like Cameroon remain an urgent need to boost research and ensure food security.

English

A field experiment was conducted to evaluate the effects of intercropping and planting densities on the growth and yield of maize (Zea mays) and soybeans (Glycine max).&nbsp; A 1 ha plot located at the Institute of Agricultural Research for Development (IRAD), Ekona, South West Region of Cameroon was used. There were two blocks: block 1 which was fertilized with 60 kg/ha NPK (20:10:10) and top dressed with urea at 50 kg N and block 2 which was unfertilized. The experimental design was a randomized complete block design with three replications and a total of 15 treatments. Treatments were intercropped combinations of maize (53,320, 40,000 and 26,666 plants/ha) and soybeans (200,000, 160,000 and 100,000 plants/ha) and six sole-cropped treatments. Intercropping affected grain yields for both soybeans and maize; however, the effect on maize was not significant (P &ge; 0.05). Maize at 53,320 plants/ha intercropped with soybeans at 200,000 plants/ha produced the maximum&nbsp; mean number of pods (34.67), pod weight (13.09 g), number of grains (69.6) and grain weight (8.66 g) per pod. The productivity of the intercropping system indicated yield advantage of 25 to 80% in the unfertilized block and 33 to 96% in the fertilized block as depicted by the land equivalent ratio of 1.25 to 1.8 and 1.33 to 1.96, respectively. All the intercropped combinations had relative value total above unity (1.32 and 1.29) in both unfertilized and fertilized blocks, respectively, meaning a high profitability of this system as compared to monocropping. Maize at a population density of 53,320 plants/ha intercropped with soybean at a plant density of 200,000 plants/ha showed the highest profitability and overall, was the best intercropping combination in this study.&nbsp; &nbsp; Key words: Intercropping, soybean, maize performance, yield.