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.

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.

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.