Social Impact Statement: The use of neglected and underutilized species (NUS) in agrosystems is a potential solution to the challenges arising from global change. These species could contribute to the equitable diversification of agricultural systems. Providing knowledge on their genetic diversity and fostering access to data and results is essential for the development of strong collaborative future research. The study addressed these issues by assessing the diversity of the largest fonio (Digitaria exilis) collection existing to date. Associated with a user‐friendly Shiny application (https://shinyapps.southgreen.fr/app/foniodiv), our results reinforce research efficiency and broaden the prospects for all actors involved in enhancing fonio and indigenous crops as valuable resources for the future.

In this paper, we present a procedure for implementing field-based high-throughput plant phenotyping (HTPP) that can be used in resource-constrained research programs. The procedure relies on opensource tools with the only expensive item being one-off purchase of a drone. It includes acquiring images of the field of interest, stitching the images to get the entire field in one image, calculating and extracting the vegetation indices of the individual plots, and analyzing the extracted indices according to the experimental design. Two populations of groundnut genotypes with different maturities were evaluated for their reaction to early and late leaf spot (ELS, LLS) diseases under field conditions in 2020 and 2021. Each population was made up of 12 genotypes in 2020 and 18 genotypes in 2021. Evaluation of the genotypes was done in four locations in each year. We observed a strong correlation between the vegetation indices and the area under the disease progress curve (AUDPC) for ELS and LLS. However, the strength and direction of the correlation depended upon the time of disease onset, level of tolerance among the genotypes and the physiological traits the vegetation indices were associated with. In 2020, when the disease was observed to have set in late in medium duration population, at the beginning of the seed stage (R5), normalized green-red difference index (NGRDI) and variable atmospheric resistance index (VARI) derived at the beginning pod stage (R3) had a positive relationship with the AUDPC for ELS, and LLS. On the other hand, NGRDI and VARI derived from images taken at R5, and physiological maturity (R7) had negative relationships with AUDPC for ELS, and LLS. In 2021, when the disease was observed to have set in early (at R3) also in medium duration population, a negative relationship was observed between NGRDI and VARI and AUDPC for ELS and LLS, respectively. We found consistently negative relationships of NGRDI and VARI with AUDPC for ELS and LLS, respectively, within the short duration population in both years. Canopy cover (CaC), green area (GA), and greener area (GGA) only showed negative relationships with AUDPC for ELS and LLS when the disease caused yellowing and defoliation. The rankings of some genotypes changed for NGRDI, VARI, CaC, GA, GGA, and crop senescence index (CSI) when lesions caused by the infections of ELS and LLS became severe, although that did not affect groupings of genotypes when analyzed with principal component analysis. Notwithstanding, genotypes that consistently performed well across various reproductive stages with respect to the vegetation indices constituted the top performers when ELS, LLS, haulm, and pod yields were jointly considered.

Despite its importance in providing income and food for smallholder farmers, fodder for livestock, and improving soil fertility through biological nitrogen fixation, groundnut yields are lowest on farmers’ fields in Sub-Saharan Africa due to biotic and abiotic constraints. Foliar fungal diseases account for over 80% reduction in groundnut productivity in some parts of Ghana. Unfortunately, chemical control of these foliar diseases has not yielded the desired results. Meanwhile, advances in phenotyping for disease tolerance in other crops have established a strong relationship between stay-green trait and foliar disease tolerance. However, this relationship has not been explored in groundnut. This study was designed to determine the genetic control of the stay-green trait and its relationship with leaf spot disease severity in groundnut. Twenty-five advanced groundnut breeding lines with varying degrees of tolerance for leaf spot tolerance were evaluated under diseased and disease-free conditions, after which four were selected for genetic studies. Results showed significant (p<0.001) differences among the genotypes for early leaf spot (ELS), late leaf spot (LLS), leaf area under greenness (LAUG), SPAD chlorophyll meter readings (SCMR), and yield traits. Leaf spot diseases caused 4.95 t·ha⁻¹ (64.54%) pod yield reduction in CHINESE, the widely cultivated groundnut variety in Ghana. There was a strong correlation between LAUG and ELS (r = 0.82, p<0.001) and LLS (r = 0.63, p<0.001), and genotypes that were stay-green had tolerance to both diseases. Stay-green trait in groundnut was detected to be under the control of a single recessive gene and hence may be used to select for ELS and LLS resistance.

Vegetable plays a key role in food and nutrition security in Ghana as the country’s food system shifts from food quantity to diet quality and health benefits. This chapter looks at the role vegetables play in the diets of humans in ensuring food and nutrition security. Traditional locally available underutilized vegetable crops as well as exotic vegetable crops could be utilized to improve nutrition and health. One of the strategies for promoting vegetable production is the development and adoption of innovative and modern technologies to address major challenges impeding the advancement of vegetable production in Ghana. These challenges include lack of improved varieties, nonfunctional seed systems, poor infrastructure for storage and processing, uncontrolled use of agrochemicals, etc. Genetic manipulation, soil and water management as well as integrated pest and disease management have been harnessed with significant achievement to boost vegetable production. Other emerging, including nursery management, controlled environment (such as a greenhouse), grafting, post-harvest handling, digital marketing, information and extension services can also be promoted. Greenhouse production increases vegetable crop quality and productivity, which results in higher economic returns. Finally, the chapter highlights the enormous prospects and contributions of vegetable production towards reducing rural poverty and unemployment.

Although sorghum plays a vital role in income generation, food, and nutritional security in Tanzania, access to quality seed and adoption of improved varieties remain low. Community‐based seed producers can enhance farmers' access to quality seed, yet their impact on the adoption of improved varieties and, subsequently, improving productivity has not been studied. Our empirical strategy relies on treatment effects matching, propensity score matching, inverse probability weighting, and regression adjustment. Data from 1492 farming households across the major sorghum‐producing regions of Tanzania showed that farmers were, on average, 35 km away from the main markets, relied on farm‐saved seeds and on their peers for information regarding production, seed knowledge, and markets. Adoption of improved sorghum varieties was at least 10% higher in treated than in control wards. The results suggest that if each ward had a QDS producer, adoption would increase by at least 14%. Farmers in treated wards allocated a minimum of 9% more of cultivated area to improved varieties compared to those in control wards. Productivity was higher among households using improved varieties, with gains of at least 55 kg/ha relative to non‐adopters. The average treatment effect ranged between 55 kg and 77 kg/ha. This estimate is a model‐based scaling scenario for the surveyed sorghum‐producing wards and should be interpreted as the expected gain from scaling out QDS producers' presence to comparable contexts. If the estimated area of 0.9 million ha of land under sorghum in Tanzania was grown to improved varieties, national production would increase by between 49,500 and 69,300 metric tons per season, translating to an estimated value of between USD 28.4 million and USD 39.8 million in additional revenue. These results underscore the importance of promoting decentralized seed production and distribution to broaden access to quality seed and increase the adoption of improved varieties and productivity in underserved communities. We propose evolving QDS production into an “in situ agrodealership” model that bundles quality‐declared seed with embedded advisory services and access to complementary inputs. This model complements (rather than replaces) private agrodealers by reaching last‐mile farmers through replicated producer networks across districts within existing QDS marketing rules, thereby increasing adoption and productivity at scale.