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Organic and inorganic farm inputs in the form of fertilizers is a management practice to improve soil fertility for the growth and development of cultivated crops. A field experiment was conducted to evaluate the growth, yield and shelf-life response of cucumber (Classico F1 and Poinsett-76) to fertilizer applications. The experimental design was a randomized complete block in split plots with three repetitions of the treatments; Control (To: No fertilizer application), poultry manure (T1:20t ha-1), urban waste compost (T2:20t ha-1), NPK-20-10-10 (T3:0.7t ha-1), poultry manure (10t ha-1)+NPK-20-10-10 (0.35t ha-1) (T4), poultry manure (10t ha-1)+urban waste compost (10t ha-1) (T5), urban waste compost (10t ha-1)+NPK-20-10-10 (0.35t ha-1) (T6). Collected data on growth and yield variables from emergence till harvest were analyzed for variation in R version 4.0.1. Results showed that variety and fertilizer had a significant effect (P < 0.05) on all growth variables with Classico F1 variety recording the highest mean values for all growth and yield variables. T1 recorded the highest in all growth variables (vine length, No. of leaves and stem diameter), except for the leaf area in T5 of Classico F1 (404.20 cm2) with the lowest in T0 of Poinsett-76 (87.87cm2). Variety, fertilizer treatments and interactions showed significant effects (P < 0.05) on yield variables. Classico F1 was superior to Poinsett-76, yielding 31.91tha-1 in T1 while Poinsett-76 produced 20.36tha-1 in the same treatment. The lowest yield was recorded in the control treatments (4.45 tha-1 for Poinsett-76 and 7.55 tha-1 for Classico F1). Shelf-life evaluation showed the highest weight loss (20%) in fruits obtained in NPK-20-10-10 treatments within 21 days of storage. These results revealed that the integration of poultry manure or urban waste compost and chemical fertilizer (NPK-20-10-10) improves the growth and yield of cucumber as well as the shelf-life of harvested fruits in the western highlands of Cameroon.

Soil salinity represents a major constraint limiting crop production in arid and semi-arid countries. The effect of salinity induced by sodium chloride (NaCl) at five levels (0, 50, 100, 150 and 200 mM) was investigated on four germination traits and thirteen seedling growth characteristics in twenty cowpea [Vigna unguiculata (L.) Walp.] genotypes (ET11, KEB-CP004, KEB-CP006, KEB-CP009, KEB-CP 010, KEB-CP020, KEB-CP033, KEB-CP038, KEB-CP039, KEB-CP045, KEB-CP051, KEB-CP054, KEB-CP057, KEB-CP060, KEB-CP067, KEB-CP068, KEB-CP118, MTA22, NO74 and NO1036). The germination tests were carried out on Petri dishes in the laboratory while seedling growth experiments continued in plastic pots in the greenhouse, both setting up using a randomised complete block design with three replications. Genotypic responses were significant for all germination traits (p < 0.001). Germination percentage, germination rate index, and coefficient of velocity of germination were all decreased by salt stress. However, the mean germination time increased with increasing saline conditions. Significant differences were found between genotypes for most growth attributes. Growth rate (centimeter increased in height per week) decreased significantly with increasing salinity, starting at 100 mM NaCl (24.20% reduction, 2.66 cm / week) with maximum reduction (38.58%) corresponding to 2.16 cm/week observed at 200 mM NaCl, compared to control (3.51 cm/week growth rate). Also, significant decline in shoot weights, number of functional leaves and dry matter production were observed under salinity. Salinity also reduced water content in shoot and root and did not affect root weights. Under salinity, significant correlations were found between all germination variables (p < 0.001). Growth rate was significantly associated with ten out of the twelve other seedling growth traits. Also, the dry matter production under salinity was significantly associated with all other seedling growth characteristics with the exception of root water content. Given the effect of salt stress, cowpea genotypes, namely NO1036, KEB-CP004, KEB-CP038 and KEB-CP051, were the most tolerant while KEB-CP068 and ET11 were the most sensitive ones. The results confirm substantial genetic variation in salt stress tolerance among the studied genotypes. The most tolerant genotypes should be further explored in genetic improvement programs and should be promoted for culture in regions affected by salinity.

In Cameroon, cowpea plays an important role in traditional agroecosystems. Genetic variation in wild and cultivated cowpea in Cameroon has not yet been documented. Allozyme markers because of their codominance and polymorphism are useful tools for studying genetic variation and disparity in plant species. The present study was undertaken to elucidate the relationship between wild and cultivated cowpea from Cameroon. Ten enzyme systems encoding nineteen isozyme loci were used on 62 cowpea germplasm (45 wild and 17 cultivated). A total of thirty-two alleles were found. One allele was only found in cultivated samples (Enp98 ). Eight alleles were specific only to wild plant (Amp2 98 , Amp3a 103 , Amp4 96 , Fdh104 , Idh2 95 , Pgi3 92 , Pgm2 95 and Sdh95 ). Twenty-three alleles were common to both wild and cultivated accessions. Amp2 10 2 (z = −4.633, p < 0.001) and Fle3 96 (z = −2.858, p < 0.010) were significantly more represented in cultivated compared to wild cowpea forms. The mean number of alleles per locus in wild (1.632 alleles/locus) cowpea were significantly higher (t = 2.805, p < 0.010) compared to cultivated (1.263 alleles/locus) cowpea. Also, the proportion of polymorphic loci (P = 52.63%) and average Nei’s genetic diversity (He = 0.126) were important in wild, compared to the cultivated plants: P = 26.31% and He = 0.063, respectively. The low level of diversity found in domesticated accessions compared to wild can be attributed to a major genetic bottleneck that probably happened during the domestication process. Cluster analysis revealed by UPGMA dendrogram separated the 62 accessions into three clusters. Although an admixture of both wild and cultivated accessions within the same cluster were found, the dendogram, however, highlighted a visible separation between wild and cultivated cowpea. Wild cowpea with many more private alleles indicates an untouched resource available for future breeding.

A field experiment was conducted to investigate the effect of aqueous and ethanolic extracts of neem (Azadirachta indica A. JUSS) and garlic (Allium sativum L.) against Cercospora leaf spot (CLS) disease of groundnut (Arachis hypogaea L.). A split plot design using two exotic (“fleur” 11 var., 65-13 var.) and one local (village var.) variety of groundnut as the main factor and ten treatments comprising one negative control (sterile distilled water), one positive control (fungicide: spavozeb) and eight phyto-extracts replicated three times was applied. Treatments were applied to plots at 45, 60, 75 and 90 days after planting (DAP). Results showed that CLS disease incidence ranged between 66.67% and 88.89% at 65 DAP for 10% ethanolic extract of garlic and 20% aqueous extract of garlic, respectively. Disease severity was lowest for 20% ethanolic extracts of neem seeds (14.74%) and garlic bulb (14.99%) at 65 DAP. Yield obtained from treatments of ethanolic extracts of garlic (3.62 t ha−1) was significantly higher (p < 0.05) than the control (2.40 t ha−1) but comparable to the spavozeb treatment (3.09 t ha−1). Exotic varieties were more productive (3.13 and 3.43 t ha−1) than the more resistant local variety (2.67 t ha−1).

Genetic variation of quantitative traits is a prevalent characteristic among cultivated tomato varieties. Twenty tomato genotypes comprising indigenous varieties and commercial cultivars, cultured in the Western Region of Cameroon were evaluated using fourteen quantitative traits for disease resistance, phenotypic divergence and heritability estimates. The experiment was carried out using a randomized completed blocks design with three replications. Data collections were disease characteristics, plant development features and yield attributes. The analysis of variance revealed significant variation among genotypes for all the experimental quantitative traits. Hybrid varieties had significantly more fruit yield (1066.00 g/plant), single fruit weight (57.28 g), fruit diameter (4.47 cm) and pericarp thickness (0.54 cm) compared to standard and indigenous varieties. These indigenous varieties were significantly more resistant to late blight, alternaria leaf spot and viral diseases. They also had significantly higher collar diameter (16.30 mm), number of primary branches per plant (8.45), number of fruit per plant (31.58) and plant height (88.33 cm) compared to standard and hybrid plants. The genotype local 2 was the third most productive (1576.39 g / plant) after Rio Semagri (1984.80 g/plant) and Sakato F1 (1691.69 g/plant). Heritability and genetic advance estimates were high for twelve of the fourteen studied quantitative traits. Fruit yield showed significant positive correlations with single fruit weight and number of fruit per plant. However, significant negative correlation was found between fruit yield and time to 50 % flowering, 50 % fruiting, 50 % maturity and viral disease. The first three and the first four components in the principal component analysis explained, respectively, 77.85 % and 88.38 % of the total variation observed among genotypes. The first component determined 41.42 % of the total variation, dominated by the collar diameter, the number of primary branches per plant and plant height. This study clearly indicated that indigenous varieties are the most disease resistant genotypes and are having substantial fruit yield (945.30 g/plant) similar to standard varieties and at a touching distance to hybrid cultivars.

This study was carried out to determine effects of salinity on germination and seedling development of commercially important common bean genotypes in Cameroon. The seeds of eight genotypes were used for both trials. The germination experiments were carried out on petri dishes in the laboratory while early growth trials continued in plastic pots in the screenhouse. Both stages were setup using a randomized complete block design with three replications. Germination and early growth trials of the different genotypes were studied using distilled water as control or osmotic potentials of 50, 100, 150 and 200mM NaCl to study the effects of salinity on germination and seedling growth characteristics. Leaf concentrations of Na+ and K+ were determined. At the germination level, germination percentage, germination index and the coefficient of velocity of germination decreased with increasing salinity while the mean germination time and time to 50% germination increased with increasing level of salt. All the growth variables decreased with increasing salinity with the exception of the root length which was not affected by salinity. It was observed that increasing salinity induced a significant increase in leaf Na+ and substantial reduction in the accumulation of K+ in the leaves. For ions accumulation, germination variables and growth parameters, significant differences at 0.001 probability levels were found among salinity treatments, common bean genotypes and most of their interactions. Significant correlations were found between all germination variables and between most growth parameters. From the effect of salt application, the common bean genotypes namely KEBCB049, KEB-CB053 and Mac-33 were the most tolerant while KEB-CB055 and KEB-CB050 were the most sensitive. The results confirm that there is genotypic variation in salinity tolerance and that the most tolerant genotypes should be further explored in selection programs, with the aim that they should be promoted for cultivation in tropical zones affected by salinity.

Characterization of the genetic diversity and analysis of the genetic relationship between accessions of a crop species is a key step in breeding superior cultivars. The main objective of the hereby study was to determine the genetic variation between 30 cowpea accessions collected throughout the eight divisions of the Western Region of Cameroon using qualitative traits. Phenotypic variation of these accessions was evaluated using diversity indices and cluster analyses. A total of twenty qualitative traits were used for the study. Fifteen of them (75%) were polymorphic, displaying each at least two phenotypic classes. The monomorphic characters were growth pattern, leaf color, leaf hairiness, plant hairiness and pod hairiness, each with only one phenotypic class. Results showed a relatively significant level of genetic diversity among the studied cowpea accessions. Overall, the average of the observed and effective number of phenotypic classes per qualitative trait were Na = 2.350 and Ne = 1.828 respectively. The Nei’s genetic diversity and the Shannon weaver diversity index were He = 0.369, ranging from zero (monomorphic trait) to 0.655 (growth habit) and H’ = 0.609, ranging from zero (monomorphic trait) to 0.996 (seed crowding), respectively. The dendrogram constructed from the twenty qualitative traits revealed 05 accessions clusters with the number of accessions in each cluster varying from one to eleven. Information obtained from this study is likely be useful for future cowpea breeding program.

This study investigates the impact of salinity (NaCl) on growth and ions accumulation in the leaves of three cowpea genotypes: OU100 and KEB-CP118 from Cameroon and ICV12 from Kenya. Four levels of salinity were used (0mM, 50mM, 100mM and 150mM) and the experiment was carried out in the greenhouse. Growth parameters were measured on 8 weeks old plants. Leaf ions concentrations (Na+, K+, K+/Na+) were determined. It was observed that increasing salinity induced significant increase in Na+ and substantial reduction in the accumulation of K+ in the leave of all genotypes. Pearson’s correlation analysis revealed significant association among most of the growth parameters. Water content in shoots was not affected by salinity for all genotypes; however salinity induced a reduction of water content in the root for ICV12 and OU100 genotypes. Generally, results highlighted that high salt concentrations significantly delayed the growth process. The delay was more pronounced for OU100 genotype. Therefore, genotype effect toward salinity tolerance was noticed. KEB-CP118 was the most tolerant genotype as salinity did not affect negatively growth parameters. Its remarkable behavior under salinity indicates it should be explored in selection programs, used in development of tolerant varieties and promoted for cultivation in tropical zones affected by salinity.