Seed production system and adaptability of okra (Abelmoschus esculentus L.) cultivars in Buea, Cameroon.

Okra is grown globally for its nutritional and economic benefits. Okra seeds ensure continuous production of the crop but challenges of poor production, adaptability and management may not allow the seeds to express their full potential. There are two seed production systems in Cameroon; the informal and formal. In Buea, the informal seed system is used by most farmers for seed production/utilization and farmers are reluctant to use hybrid seeds. This study aimed to assess the informal seed system of okra and evaluate the adaptability of seed produce from informal and formal systems in Buea. A survey and a field experiment were carried out. The designs for the survey and field experiment were stratified random sampling and randomized complete block design respectively. Data collection for the survey was done using questionnaires and other data collection instruments, while for the field experiment, data was collected on germination, vegetative growth parameters, incidence and severity of pests / diseases and yield. Data analysis for the survey was done using descriptive statistics, while data from the field experiment was done using a two-way ANOVA test and treatment means compared using the Tukey test at 5% probability. Results from the survey showed that women (60%) were mostly involved in seed production by mass selection from two landraces identified. Preservation of seeds was mostly done with the use of wood ash (58%) and insects were the major postharvest pest (76%). For the field experiment, at 66 DAP, Yellen recorded the highest significant number of leaves (13.417), leaf area (771.4 cm2) and the number of branches (5.64). Clemson spineless recorded the highest significant incidence (89.9%) and severity for pests / diseases while Kirikou and Landrace recorded the least incidence (0.0%) and severity. Kirikou recorded the highest significant yield (6.0 tons/ha), followed by Landrace (5.3 tons/ha). These findings reveal the performance of the landrace and provide reasons why farmers in Buea are reluctant to use hybrid okra seeds. The Landrace should certainly have adaptable genes, coupled with the autogamous nature of okra which encourages inbreeding for homozygous traits, which are dominant in expression compared to heterozygous traits.

Inoculating plant growth-promoting bacteria and arbuscular mycorrhiza fungi modulates rhizosphere acid phosphatase and nodulation activities and enhance the productivity of soybean (Glycine max).

Soybean [Glycine max (L.) Merrill] cultivation is important for its dual role as rich source of dietary protein and soil fertility enhancer, but production is constrained by soil nutrient deficiencies. This is often resolved using chemical fertilizers that exert deleterious effects on the environment when applied in excess. This field study was conducted at Nkolbisson-Yaoundé in the agro-ecological zone V of Cameroon to assess the performance of soybean when inoculated with plant growth-promoting bacteria (PGPB) and arbuscular mycorrhiza fungi (AMF), with or without NPK fertilizer addition. Ten treatments (Control, PGPB, AMF, PGPB+AMF, PGPB+N, PGPB+PK, PGPB+N+PK, PGPB+AMF+N, PGPB+AMF+PK, and PGPB+AMF+N+PK) were established in a randomized complete block design with three replicates. Mycorrhizal colonization was only observed in AMF-inoculated soybean roots. In comparison to control, sole inoculation of PGPB and AMF increased the number of root nodules by 67.2% and 57%, respectively. Co-application of PGPB and AMF increased the number of root nodules by 68.4%, while the addition of NPK fertilizers significantly increased the number of root nodules by 66.9-68.6% compared to control. Acid phosphatase activity in soybean rhizosphere ranged from 46.1 to 85.1 mg h-1 kg-1 and differed significantly across treatments (p < 0.001). When compared to control, PGPB or AMF or their co-inoculation, and the addition of NPK fertilizers increased the acid phosphatase activity by 45.8%, 27%, 37.6%, and 26.2-37.2%, respectively. Sole inoculation of PGPB or AMF and their integration with NPK fertilizer increased soybean yield and grain contents (e.g., carbohydrate, protein, zinc, and iron) compared to the control (p < 0.001). Soil phosphorus correlated significantly (p < 0.05) with soybean grain protein (r = 0.46) and carbohydrate (r = 0.41) contents. The effective root nodules correlated significantly (p < 0.001) with acid phosphatase (r = 0.67) and soybean yield (r = 0.66). Acid phosphatase correlated significantly (p < 0.001) with soybean grain yield (r = 0.63) and carbohydrate (r = 0.61) content. Effective root nodules correlated significantly with carbohydrate (r = 0.87, p < 0.001), protein (r = 0.46, p < 0.01), zinc (r = 0.59, p < 0.001), and iron (r = 0.77, p < 0.01) contents in soybean grains. Overall, these findings indicate strong relationships between farm management practices, microbial activities in the rhizosphere, and soybean performance.