No abstract

Finger millet is one of the most important cereals that are often grown in semiarid and arid regions of East-Africa. Salinity is known to be a major impediment for the crop growth and production. This study was aimed to understand the mechanisms of physiological and biochemical responses to salinity stress of Kenyan finger millet varieties (GBK043137, GBK043128, GBK043124, GBK043122, GBK043094, GBK043050) grown across different agroecological zones under NaCl-induced salinity stress. Seeds were germinated on the sterile soil and treated using various concentrations of NaCl (100, 200 and 300 mM) for two weeks. Again, the earlyseedling stage of germinated plants was irrigated with the same salt concentrations for 60 days. Results indicated depression in germination percentage, shoot and root growth rate, leaf relative water content, chlorophyll content contents, leaf K + concentration, and leaf K + /Na + ratios increased salt levels. Contrary, proline and malonaldehyde (MDA) contents reduced sugar content and leaf total proteins. At the same time, the leaf Na + and Clamounts of all plants increased substantially with rising stress levels. Clustering analysis revealed that GBK043094 and GBK043137 were placed together and identified as salt-tolerant varieties based on their performance under salt stress. Overall, our findings indicated a significant varietal variability for most of the parameters analysed. These superior varieties identified could be potentially used as promising genetic resources in future breeding programmes development directed towards salt-tolerant finger millet hybrids. Further analysis at genomic level need to be undertaken to better understand the genetic factors that promote salinity tolerance in finger millet.

Sustainable intensification of agriculture in Africa is essential for accomplishing food and nutritional security and addressing the rising concerns of climate change. There is an urgent need to close the yield gap in staple crops and enhance food production to feed the growing population. In order to meet the increasing demand for food, more efficient approaches to produce food are needed. All the tools available in the toolbox, including modern biotechnology and traditional, need to be applied for crop improvement. The full potential of new breeding tools such as genome editing needs to be exploited in addition to conventional technologies. Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas)-based genome editing has rapidly become the most prevalent genetic engineering approach for developing improved crop varieties because of its simplicity, efficiency, specificity, and easy to use. Genome editing improves crop variety by modifying its endogenous genome free of any foreign gene. Hence, genome-edited crops with no foreign gene integration are not regulated as genetically modified organisms (GMOs) in several countries. Researchers are using CRISPR/Cas-based genome editing for improving African staple crops for biotic and abiotic stress resistance and improved nutritional quality. Many products, such as disease-resistant banana, maize resistant to lethal necrosis, and sorghum resistant to the parasitic plant Striga and enhanced quality, are under development for African farmers. There is a need for creating an enabling environment in Africa with science-based regulatory guidelines for the release and adoption of the products developed using CRISPR/Cas9-mediated genome editing. Some progress has been made in this regard. Nigeria and Kenya have recently published the national biosafety guidelines for the regulation of gene editing. This article summarizes recent advances in developments of tools, potential applications of genome editing for improving staple crops, and regulatory policies in Africa.

Yam (Dioscorea spp.) is an economically important crop grown in the tropical and subtropical regions, producing tuberous roots that serve as a staple food, an income source, and an excellent source of various pharmaceutical precursors. Yam production is constrained by disease and pest infestations and a range of abiotic stresses. Genetic improvement can significantly mitigate these challenges, improve productivity, expand the yam markets, and increase economic gains. However, several intrinsic attributes of the crop have curtailed progress in yam breeding. Advanced genetic engineering such as genome editing by sequence‐specific nucleases has emerged as complementary approaches to conventional breeding techniques. Mainly, the clustered regularly interspaced short palindromic repeats/CRISPR‐associated protein (CRISPR/Cas) system for genome editing has provided robust platforms for gene function analysis and crop improvement in the post‐genomic era. Despite its significance, research towards improving the yam species remains under‐represented compared to other staple tuber crops such as cassava and sweet potato. Thus, it is critical to explore avenues for increasing the genetic gains from this under‐exploited crop. The present review focuses on the progress and prospects for applying the CRISPR/Cas technology for yam improvement. The study elaborates on the currently available CRISPR/Cas tool for yam genome engineering and explores the potential applications of this toolkit in mitigating the various challenges encountered in yam production and consumption. Furthermore, we have delved into the challenges associated with this technology and the improvements made to minimize these challenges. The insights presented herein provide a guide for yam improvement to increase genetic gains from this under‐researched and under‐utilized resource.

No abstract

Banana (Musa spp) is among the top ten most important food crops worldwide in terms of production and consumption. However, banana production is threatened by several bacterial diseases, including Banana Xanthomonas wilt (BXW) caused by Xanthomonas campestris pathovar (pv). musacearum, Moko disease caused by Ralstonia solanacearum, and Blood disease caused by Ralstonia syzygii sub-species (subsp). Celebesensis. Banana Xanthomonas wilt (BXW), caused by Xanthomonas campestris pv. musacearum (Xcm) is the most economically important bacterial disease affecting banana production, particularly in the African Great Lakes region. Banana breeding through conventional approach is key to overcoming yield losses to bacterial phytopathogens. However, conventional breeding of bananas is limited by low male and female fertility and the lack of diversity and important traits in the gene pool. At present, only Musa balbisiana (banana progenitor species) is resistant to BXW, but breeders do not prefer it for breeding because it harbors banana streak virus (BSV) sequences in its B genome, which get activated during abiotic stress, such as drought, leading Banana Streak Disease (BSD). Thus, genetic engineering serves as a viable alternative and complement to conventional breeding for banana improvement. This review highlights the strategies, challenges, status, and prospects of genetic engineering of bananas against bacterial diseases.

No abstract

Finger millet is one of the most important cereals that are often grown in semiarid and arid regions of East-Africa. Salinity is known to be a major impediment for the crop growth and production. This study was aimed to understand the mechanisms of physiological and biochemical responses to salinity stress of Kenyan finger millet varieties (GBK043137, GBK043128, GBK043124, GBK043122, GBK043094, GBK043050) grown across different agroecological zones under NaCl-induced salinity stress. Seeds were germinated on the sterile soil and treated using various concentrations of NaCl (100, 200 and 300 mM) for two weeks. Again, the early-seedling stage of germinated plants was irrigated with the same salt concentrations for 60 days. Results indicated depression in germination percentage, shoot and root growth rate, leaf relative water content, chlorophyll content contents, leaf K+ concentration, and leaf K+/Na+ ratios increased salt levels. Contrary, proline and malonaldehyde (MDA) contents reduced sugar content and leaf total proteins. At the same time, the leaf Na+ and Cl− amounts of all plants increased substantially with rising stress levels. Clustering analysis revealed that GBK043094 and GBK043137 were placed together and identified as salt-tolerant varieties based on their performance under salt stress. Overall, our findings indicated a significant varietal variability for most of the parameters analysed. These superior varieties identified could be potentially used as promising genetic resources in future breeding programmes development directed towards salt-tolerant finger millet hybrids. Further analysis at genomic level need to be undertaken to better understand the genetic factors that promote salinity tolerance in finger millet.