African Journal of Horticultural Science

Assessment of the Mineral Elements in the Soil of a Bixa Field and their Distribution in various Plant Tissues on Application of Organic and Inorganic Fertilizer Amendments

F. N. Pole, Prof, L. A. Wasilwa, Joseph Gweyi-Onyango — Sat, 21 Oct 2023 00:00:00 +0000

Bixa orellana L. is a shrub that is commercially known as ‘annato’. Its main product is organic dye, which is present in the seed coat, commercially called ‘annatto’. It is widely used in the cosmetic and the food industry for giving red to orange-yellow colours to foodstuffs and cosmetic products. Bixa farming in Kenya has declined since the 1970’s due to the use of cheap synthetic materials as food and cosmetic colours, which have proved to be carcinogenic. This has triggered a high demand for natural colours from bixa. However, the quality of bixa remains low due to suboptimal application of fertilizers. The objective of this study was to determine the mineral elements in the soil and their distribution in tissues of bixa plants treated with organic and inorganic fertilizer amendments for increased bixa quality. A study was undertaken at the Bixa Company farm at Shimoni in Kwale County in 2018 and 2019. Bixa plants of the same age were applied with different levels of organic (poultry manure at 5 tons/ha and 10 tons/ha) and inorganic fertilizers (NPK 17:17:17 at 100 kg/ha and 150 kg/ha) and a combination of the two (2.5 tons/ha plus 50kgs/ha NPK and 5 tons/ha plus 75kgs/ha NPK) with a control in a randomized complete block design with three replications. Bixa roots, stems and leaves were analyzed for the distribution of both macro and micro nutrients. The data obtained was subjected to ANOVA using SAS version 8.2. Significant means were separated using LSD at α = 0.05. The study revealed that application of manure at the rate of 10t/ha and NPK at the rates of 100kg/ha and 150kg/ha significantly (p < 0.05) improved soil fertility and nutrient levels in the various plant tissues compared to the other treatment combinations. More nutrients were found in the leaves followed by stems and then the roots. At the same time the quality of the bixa produced was higher in the three treatments than the rest.

Effect of Seed Rate, Planting Method and Location on the Yield of Corchorus olitorius in the Greater Accra Region

Naomi Weimer, Frank Kofi Kumaga, George Oduro Nkansah — Sat, 21 Oct 2023 00:00:00 +0000

Corchorus olitorius is a traditional vegetable in Ghana. It is relatively affordable and has become a popular alternative to okra (Abelmoschus esculentus), especially when okra becomes expensive in the market. However, there is limited information on its recommended agronomic practices such as seed rate and planting method. Therefore, there is the need to develop appropriate agronomic practices for the optimal production of Corchorus olitorius. A 2 x 2 x 4 factorial experiment was carried out to determine the effect of location, planting method and seed rate on the yield of Corchorus olitorius. There were three factors, that is, location (University of Ghana Research Farm and Amrahia), planting methods (broadcasting and drilling) and seed rates (0.5 gm^-², 0.6 gm^-², 0.7 gm^-² and 0.8 gm²). Data was collected on fresh and dry weight of leaves, stems and branches and roots per area. The data was subjected to analysis of variance (ANOVA) using GenStat statistical software (12^th Edition) to determine the effect of various treatments on yield. Tukey’s test was used to separate significant means at 5% probability. The result of the study showed that generally, there was a significant increase (p <0.05) in fresh and dry yield of Corchorus olitorius with higher seed rates, the drilling method and at the location with a higher soil nitrogen content. The highest fresh yield of leaves of 1989.1 gm^-2(19.89 tha^-1) was produced by drilling Corchorus olitorius seeds at a seed rate of 0.8 gm^-2at the University of Ghana Research Farm. It is therefore recommended that Corchorus olitorius is drilled at 0.8 gm^-2 for a higher return.

Arbuscular Mycorrhizal Fungi and Trichiderma spp Influence on Nutrient Uptake and Water Stress Tolerance in Cowpea (Vigna unguiculata L. Walp)

Daniel Wanjala, Adelaide Mutune, Ezekiel Mugendi Njeru — Sat, 21 Oct 2023 00:00:00 +0000

Drought and nutrient un-availability are amongst the major environmental stresses that hinder plants productivity. The use of synthetic fertilizers in drought-stricken lands is unaffordable to most small-holder farmers and contributes to environmental pollution. This study was conducted to determine the influence of Arbuscular Mycorrhizal fungi and Trichoderma spp on nutrient uptake in cowpea at different soil water levels under greenhouse conditions. The experiment was conducted using a 3 × 2 × 8 factorial arranged on a completely randomized block design with the three water levels treatment of90 % (no stress), 60 % (mild stress), and 30 % (severe stress) of field capacity (FC). Two cowpea varieties (KVU 27-1 and K80) were used in each water level and each was subjected to eight fungal inoculation treatments: Funneliformis mosseae, Rhisophagus irregularis, Trichoderma harzianum, Trichoderma asperellum, Funneliformis mosseae + Rhisophagus irregularis, Trichoderma harzianum + Trichoderma asperellum, T. harzianum + Funneliformis mosseae + Rhisophagus irregularis, and control (un-inoculated) that were in the replicates of four. The shoot tissue analysis was done to determine the nitrogen (N), phosphorous (P) and potassium (K) contents. The data were subjected to a Two-Way ANOVAto determine the influence of the two fungi on nutrient uptake.Means were separated using Bonferroni at p < 0.05. Results showed that all the shoot nutrient contents were significant at (p<0.05) with soil water level treatment in both varieties. Water stress negatively influenced shoot nutrient contents. The combined inoculation of HarS and HBB greatly influenced shoot nutrient levels for both cowpea varieties than the controls. The highest N and P shoot content were 3.7 % (in KVU 27-1) and 0.12 % (in K80) inoculated with HBB and HarS respectively. The highest K content was 2.7 % in both varieties inoculated with HarS. Therefore, co-inoculation of HarS and HBB was the most appropriate to nutrient uptake in the cowpea varieties.

Phylogenetic Relationship of Three Lettuce species (Lactuca spp.) based on their Molecular Profiles using RAPD Markers

Alexander Jason, Pudji Widodo, Nurtjahjo Dwi Sasongko — Sat, 21 Oct 2023 00:00:00 +0000

Lactuca spp., Asteraceae, like: Green lettuce (L. sativa) is the most common type of lettuce grown, while the spiny (L. serriola) and wild lettuce (L. virosa)have not been cultivated so far in Indonesia. The current study explores those three species morphological and molecular characters. The data obtained are then used to elucidate the genetic relationship among the species. The genomic DNA was extracted from each sample and measured for their qualities and quantities. The extracted genomic DNA subjected to RAPD-PCR (Random Amplified Polymorphic DNA) using eight primers as follows: OPF-1, OPF-2, OPF-3, OPF-4, OPC-11, OPAE-5, OPA-2, OPAM-7. The total number of DNA bands were evaluated for polymorphic or monomorphic patterns. The polymorphic bands were analysed using the MEGA 6 software applying a maximum parsimony method to obtain the cladogram of the samples. The RAPD-PCR obtained a total of 91 amplicons, where 84 (92.3%) of the 91 amplicons were are polymorphic and 7 amplicons were monomorphic. Primers that produced the highest polymorphism are OPF-1, OPF-4, OPC-11, OPAE-5, OPA-2 (100%) and OPAM-7. OPAM-7.produced the highest number of DNA bands, 20 DNA bands).The relationship among these three species showed that L. serriola and L. virosa have the closest genetic distance with a bootstrap 100%. The cladogram following the maximum parsimony analysis grouped the species into two clads, i.e., clad I and clad II. Clad I consists of L. serriola and L. virosa, clad II consists of L. sativa only.

The effects of gibberellic acid and short-day treatments on growth and flowering of Chrysanthemum morifolium cv. Breeze cassus

Pesanai Zanamwe, Rene Tong — Sat, 21 Oct 2023 00:00:00 +0000

Chrysanthemum morifolium cv. Breeze cassus that is widely grown as a commercial pot plant in South Africa grow short and branch poorly under the usual photoperiodic conditions. It was hypothesised that understanding the effects of gibberellic acid (GA₃), a plant hormone that promotes flowering and stem elongation in plants, may aid in improving its quality. To study this, the vegetative growth and flowering characteristics of Chrysanthemum morifolium cv. Breeze cassus plants treated with GA₃once, i.e., three weeks after transplanting, GA₃ twice, i.e., three and five weeks after transplanting, gibberellin biosynthesis inhibitor, daminozide, and short-day photoperiod were evaluated. Data was collected on plant height, number of branches per plant, time to flowering, flower buds per plant and flower size and subjected to analysis of variance. Plants treated with a short day photoperiod flowered early compared to the control. However, the plant height and flower buds per plant were significantly (p < 0.05) reduced. The final plant height of short-day photoperiod and daminozide treated plants were not statistically (p > 0.05) different. Both GA₃ treatments significantly (p < 0.05) increased plant height compared to the control, daminozide and short-day photoperiod treated plants. Plants treated with GA₃twice were significantly (p < 0.05) taller compared to plants treated with GA₃once. Treatment with GA_3,either once or twice, had no effect on time to flowering, however, treating plants with GA₃once, significantly increased flower buds and treating plants with GA₃ twice significantly increased flower diameter compared to the control. It was noted that treatment of Chrysanthemum morifolium cv. Breeze cassus with short-day photoperiod and GA₃ have different effects on plant growth and flowering. It was, therefore, concluded that, although GA₃ increases plant height of Chrysanthemum morifolium cv. Breeze cassus, it may not replace short day photoperiod treatment where early flowering is desired.

Salinity and Sodicity Induced Responses on Total Phenols, Flavonoids and Tannins Accumulation on Cowpea (Vigna unguiculata (L) Walp)

T Mutuku, E Mamati, Adelaide Mutune — Sat, 21 Oct 2023 00:00:00 +0000

Food shortage remains a developmental hindrance in globally with about 25% of world’s population suffering from continued food and nutritional insecurity especially in ASALs. Reduced arable tracts of land for cultivation, increased population and variation in non-living factors such as water and salinity are challenges facing the world. Cowpea is commonly grown on ASALs which are greatly affected by salinity. The study involved 4 cowpea varieties; K80, M66, Kunde 1 and KVU 27-1 that were subjected to both CaCl_2(aq)and NaCl_(aq) at levels of 0 (control), four, eight and twelve dS/m. A complete randomized design in replicates of three in a greenhouse was used at Jomo Kenyatta University of Science and Technology, Juja Sub county, Kiambu County on October 2021-January 2022.The salts concentrations (NaCl and CaCl₂) were applied to the soil from time of sowing and constant levels were monitored throughout by use of an EC probe Determination of total phenols, tannins, and flavonoids content was done using a UV-VIS spectrophotometer. The obtained data were evaluated using 2-way ANOVA at 5% significance level using SPSS (software version 21). As salinity and sodicity levels increased, the phenols, tannins and flavonoids content also increased. Variety M66 recorded the highest total phenols, tannins and flavonoids above 8 dS/m hence it developed a defense mechanism against salt stress. Therefore, variety M66 was better adapted to high salt levels because it performed better at high saline and sodic levels. Therefore, farmers especially in marginal areas affected by salinity should adopt growing of M66 cowpea variety.