African yam bean is a versatile legume crop, relished for its protein rich tubers, seeds and leaves which are utilized as spinach. It is a highly adaptable crop capable of producing growth even on acid and highly leached sandy soils. A pot experiment was conducted at Botswana College Agriculture to determine nodulation of African Yam Bean with Rhizobium indigenous to soils of Botswana. Soil collected from two different sites at Botswana College of Agriculture were used with each planted with African Yam Bean and cowpea plants. No fertilizer supplementation was added to the soils. Data was collected after eight weeks of establishment. The parameters measured were the number of nodules, nodule weight and plant weight. The data was analysed using Genstat software Discovery Version. African Yam Bean formed nitrogen fixing nodules under the soils from the two different sites. It compared favorably with cowpea because there were no significant differences in nodulation (nodule number and nodule weight, fresh and dry weight) between the two species. This study has further revealed that African Yam Bean is adaptable to a wide variety of environments and could be successfully grown in Botswana without expensive inputs such as inorganic fertilizers.

Abstract-

Two tymoviruses were identified in plants of Diascia x hybrida 'Sun Chimes Coral' that exhibited chlorotic mottling and reduced growth. A strain of Nemesia ring necrosis virus (NeRNV) designated NeRNV-WA was detected in symptomatic plants; the deduced amino acid sequence is virtually identical to that of the previously reported NeRNV-Nf from Nemesia fruticosa. Sequence analysis also revealed the presence of a new tymovirus, and the entire genomic sequence of this virus was determined. The genome of 6,290 nucleotides was organized into three potential open reading frames (ORFs) typical of viruses in the genus Tymovirus. Based on sequence identity to tymovirus sequences, ORFs I to III encoded the replicase, movement protein and coat protein, respectively. Amino acid sequence identities to those of NeRNV-Nf were 84.8, 50.3 and 94.8%, respectively. The 5'-untranslated region could potentially form four hairpin structures. Secondary structure analysis of the 3'-terminus showed that the RNA can form a transfer-RNA-like structure that has an anticodon specific for histidine. Only 77.9% nucleotide identity was found when complete genomic sequences of this tymovirus from diascia and NeRNV-Nf were compared. The name Diascia yellow mottle virus (DiaYMV) is proposed for this new tymovirus.

A study was carried out in forest reserves located in Chobe district in Botswana to assess the effect of dieback and associated causes on Mukwa tree, Pterocarpus angolensis Fire, elephant damage and dieback were assessed in Chobe and Kazuma forest reserves and Pandamatenga farming area. Fire damage frequency on mukwa trees ranged between 60 to 100 % and was highest in Pandamatenga and Chobe forest reserves. The frequency of elephant damage in Kazuma and Chobe forest reserves was 75 and 100 % respectively. There was no elephant damage in Pandamatenga farms because the area is fenced out and minor dieback occurred in the area. All areas under study experienced 100 % incidence of dieback, but the severity ranged from 22 to 100 %, the highest being at Chobe forest reserve and the lowest at Pandamatenga. Severity of dieback was associated with elephant damage and age of P. angolensis trees. The incidence of dieback was correlated with DBH and tree age. The results indicate that the cause of dieback is mostly due to elephant and fire damage.

In Botswana, approximately 40% of the population live in rural areas and derive most of their livelihood from agriculture by keeping livestock and practising arable farming. Due to the nature of their farming practises livestock and crops are exposed to diseases and environmental stresses. These challenges offer opportunities for application of biotechnology to develop adaptable materials to the country's environment. On the other hand, the perceived risk of genetically modified organisms (GMOs) has dimmed the promise of the technology for its application in agriculture. This calls for a holistic approach to the application of biotechnology to address issues of biosafety of GMOs. We have therefore assessed the potentials, challenges and opportunities to apply biotechnology with specific emphasis on agriculture, taking cognisance of requirement for its research, development and application in research and teaching institutions. In order to achieve this, resource availability, infrastructure, human and laboratory requirements were analyzed. The analysis revealed that the country has the capacity to carry out research in biotechnology in the development and production of genetically modified crops for food and fodder crops. These will include gene discovery, genetic transformation and development of systems to comply with the world regulatory framework on biosafety. In view of the challenges facing the country in agriculture, first generation biotech crops could be released for production. Novel GM products for development may include disease diagnosis kits, animal disease vaccines, and nutrient use efficiency, drought, and pest and disease resistant food and fodder crops.