Plants have evolved many mechanisms to increase the chance of gene dispersal mainly through pollen and environmental factors play an important role. Understanding the mechanism behind gene dispersal is therefore crucial in the correct evaluation of the use of genetically modified crops for cultivation. In this paper we address the question of weather nutrient availability for the female affects the outcome of pollen competition between two pollen donor cultivars of Cucumis sativus. We do this by carrying out controlled crosses of female plants grown at three different nutrient levels. We separated the effect of a specific donor from the effect of pollen tube growth rate by using reversed crosses of fast and slow pollen. Our results show that female effects on siring ability vary with nutrient level. Pollen with a high pollen tube growth rate was more successful when nutrient availability for the female was high. This could be the result of selection on the female to adjust preference according to environmental circumstances. Pollen tube growth rate was measured under nutrient rich circumstances, thus high performers possessed traits adapted to a nutrient rich situation. Due to trade-off effects, these traits might not be advantageous in poor environments. Instead, individuals adapted to low nutrient circumstances will have a higher pollen tube growth rate. If siring ability varies with the environment of the recipient plant, this means that assessments of gene flow must account for this variation and include both pollen donors and recipient plants subjected to a range of environmental circumstances. In risk assessments of transgenic plants, plants are often kept under experimental, homogenous conditions. If our results also apply to other species, estimates of gene flow under constant conditions may be misleading. Selection on siring ability and female preference have fundamental effects on gene flow and need to be considered in risk assessments of transgenic plants.
A workshop on ticks and tick-borne diseases (T&TBDs) was held on June 25 and 26, 2019, at the Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Arusha, Tanzania. The objectives of the workshop were to discuss the current situation and to formulate actionable strategies to improve surveillance and control of T&TBDs in Africa. The workshop was funded by the National Research Foundation and the Cape Peninsula University of Technology and attended by livestock health providers, farmers, and researchers from East, West, and Southern African countries. During the workshop, experts presented recent surveillance data focused on T&TBDs; participants discussed research opportunities and community engagement. The primary outcome of the workshop was the creation of a new research consortium known as The African Consortium for T&TBDs. The consortium is intended to function as a community for researchers, students, farmers, policymakers, extension workers, and community members who are interested in the advancement of T&TBD control. The consortium will engage in research activities that focus on comprehensive surveillance of T&TBDs, developing tick acaricide resistance, alternative tick control programs, and policy development and education. These areas were identified as top priorities to be developed to improve T&TBD control on the continent.
We explore how seed systems enhance access to seeds, and information for climate-change adaptation in farming communities in Kenya, Tanzania and Uganda, as well as how gender-driven roles and institutional dynamics influence the process. Men and women farmers equally experience climate-change related effects, including drought, short rainy seasons and increased pest and disease incidence. Our study relies on exploratory data analysis of 1001 households surveyed in four sites in 2016. Farmers surveyed preferred early-maturing, heat-tolerant, high-yielding, and pest- and disease-resistant varieties, all important climate-adaptive traits. Seed systems of the focus crops studied are largely informal—overall, 68% women and 62% men use their own seed, indicating women’s higher reliance on ‘informal’ seed and information sources. Only 21% of respondents reported interacting with seed experts who are affiliated with formal organizations. Both formal and informal organizations play a key role in providing access to climate-adapted seed/information, with access for men and women varying across the countries studied. There is a need to support further development of those connections, building on existing social networks. We conclude that inclusive and gender-responsive context- and country-specific seed interventions will ensure equitable outcomes, increase women’s empowerment and strengthen both formal and informal seed systems for more effective climate-change adaptation.
In planta Agrobacterium tumefaciens-mediated transformation of marula, Sclerocarya birrea subsp. caffra (Anacardiaceae) resulted in chimeric transgenic in vitro shoots at a rate of 0.8-1.5%. Average transgene expression rates of 33.1 and 1.3% GUS-positive explants were observed on days 3 and 6 after agroinfection, respectively. One to 4 GUS-positive zones were observed per GUS-positive explant section. Addition of acetosyringone (100 lM) during co-cultivation significantly improved transient transformation efficiency as determined by the percentage of GUS-positive explants on day 3 (p < 0.05) whereas wounding did not show a significant effect. However, wounding and acetosyringone acted antagonistically reducing transient transformation rates.
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