Cassava is an important crop in sub-Saharan Africa for food security, income generation, and industrial development. Business-oriented production systems require reliable supplies of high-quality seed. Major initiatives in Nigeria and Tanzania have sought to establish sustainable cassava seed systems. These include the deployment of new technologies for early generation seed (EGS) production; the promotion of new high-yielding and disease-resistant varieties; the updating of government seed policy to facilitate enabling certification guidelines; the application of ICT tools, Seed Tracker and Nuru AI, to simplify seed system management; and the establishment of networks of cassava seed entrepreneurs (CSEs). CSEs have been able to make profits in both Nigeria (US$ 551–988/ha) and Tanzania (US$ 1,000 1,500/ha). In Nigeria, the critical demand driver for cassava seed businesses is the provision of new varieties. Contrastingly, in Tanzania, high incidences of cassava brown streak disease mean that there is a strong demand for the provision of healthy seed that has been certified by regulators. These models for sustainable cassava seed system development offer great promise for scaling to other cassava-producing countries in Africa where there is strong government support for the commercialization of the cassava sector.

Cassava breeding faces obstacles due to late flowering and poor flower and seed set. The acceleration of breeding processes and the reduction in each cycle’s duration hinge upon efficiently conducting crosses to yield ample progeny for subsequent cycles. Our primary objective was to identify methods that provide tools for cassava breeding programs, enabling them to consistently and rapidly generate offspring from a wide array of genotypes. In greenhouse trials, we examined the effects of the anti-ethylene silver thiosulfate (STS) and the cytokinin benzyladenine (BA). STS, administered via petiole infusion, and BA, applied as an apical spray, combined with the pruning of young branches, significantly augmented the number of flowers. Controls produced no flowers, whereas treatments with pruning plus either BA or STS alone produced an average maximum of 86 flowers per plant, and the combination of pruning, BA and STS yielded 168 flowers per plant. While STS had its primary effect on flower numbers, BA increased the fraction of female flowers from less than 20% to ≥87%, thus increasing the number of progeny from desired parents. Through field studies, we devised an optimal protocol that maintained acceptable levels of phytodamage ratings while substantially increasing seed production per plant compared to untreated plants. This protocol involves adjusting the dosage and timing of treatments to accommodate genotypic variations. As a result, cassava breeding programs can effectively leverage a diverse range of germplasm to develop cultivars with the desired traits.

Cassava fresh root yield and dry matter content constitute major determinants of demand by end-users. Increased demand for the seeds of improved varieties will facilitate the development of a sustainable seed system. However, for wide acceptability, there is a need to continuously evaluate candidate varieties for stability across different agroecological zones. Participatory Demand Creation Trials (DCTs) were established to evaluate cassava varieties with farmers and processors utilizing the best agronomic practices. The multi-year DCTs were conducted in 20 environments (7 locations) during the 2016–2017, 2017–2018, 2018–2019, and 2019/2020 cropping seasons with two replications. The plot sizes were 320 m² with a spacing of 1 m × 0.8 m. The traits evaluated were Plant Vigor (PV), root number, fresh yield, dry yield, Dry Matter Content (DMC), and bundle estimation. The traits were subjected to a GGE biplot in R software to identify high-yielding and stable genotypes. Results obtained from the 20 environments showed that genotype (G), environment (E), and GXE interaction effects were significant (p < 0.01) for all the traits but PV. The heritability ranged from 56% (PV) to 96% (DMC). The average fresh yield t/ha ranged from 25.5 (IBA30572) to 35.4 (IBA980505). The DMC ranged from CR36/5 (36.1%) to IBA010040 (30.7%). The dry yield ranged from 8.8% (IBA30572) to 11.4 (IBA980505). Estimated bundles ranged from 13.5 (CR36-5) to 15.7 (IBA950289). Three varieties, IBA961632, TMEB419, and CR36/5, were identified as the most promising high dry matter content varieties for cassava processors and farmers in Nigeria, and genotype IBA961632 was the most stable. The study revealed greater genotypic effects than from the environment and high genetic advances.

Cassava (Manihot esculenta Crantz) is an important crop for humans due to its staple and industrial values. Currently the demand is more than the supply as the current output falls below the expected. This necessitated the breeding of superior genotypes that are high yielding. These superior genotypes also requires a fertile soil for optimum production. However, this has been primarily achieved through the application of organic manures and inorganic fertilizers. It is then important to evaluate four newly released cassava varieties in an organically enriched soil relative to the local best variety. Four newly released cassava varieties, Hope, Obasanjo2, Baba 70, and Game changer, and one Local Best (LB) was planted in 5-years fallowed farm lands at three plots (A, B and C) for 2 seasons. It was a three-way factorial (5-varieties*3-farms*2-seasons) arranged in a randomized complete block design and replicated three times. Data were taken on the Fresh Tuber Weight (FTW) and Stem Height (SH) per variety, and pre and post soil status. Data were analyzed using analysis of variance, while differences in varietal means were separated using least significant differences at 5% level of significance. The FTW and SH differed significantly across varieties, years and interaction between variety, farms and year, and ranged from 19.2 ± 0.5 (LB) to 41.0 ± 0.5 (Obasanjo2), 32.1 ± 0.4 (farm C) to 34.1 ± 0.4 (farm A), 30.4 ± 0.3 (year two) to 35.0 ± 0.3 (year one), and the interactions between variety and year, farms and year, and variety, year and farms were significant. The soil macro and micro elements declined in the post relative to the pre status. The fresh yield of the improved varieties Baba70, Game change, Hope and Obasanjo2 was 74%, 80.8%, 81%, and 113% higher than the local best, respectively. Yield declined in the second season due to decline inherent soil nutrient hitherto compensated by shifting cultivation in the farming community.

The multi uses of cassava plant (Manihot esculenta Crantz) has increased its demand and value. However, the production rate is far below the potential as a result of use of unimproved varieties and lack of soil amendment to enhance productivity. This study thus compared the performances of some old and newly released cassava varieties in both organic, inorganic and unamended soil at Ogbagu Ogume. Stems of newly released (Obasanjo2, Baba70, and Game changer) and old (TME419 and Give-Me-Chance-GMC) were planted in farmlands amended with 400 kg/ha NPK 15:15:15, 4.2 t/ha poultry manure and 5-year old fallowed land (control) for 2023 and repeated in 2024 planting seasons. The experimental design was a 5(varieties) x 3(nutrient source) x 2(seasons) factorial arranged in a randomized complete block design and replicated three times. The soil and leaf macro and microelements were also determined using standard procedures. Data were taken on the fresh tuber weight (FTW) at harvest. Data collected were analysed using ANOVA and means were separated using least significant differences at 5% significance level. The macro and micro elements of the soil decreased from the pre to post status while the leaf nutrient content were insignificant across the genotypes. The FTW differed significantly across the varieties, nutrient source and year and ranged from 21.33±0.59 (TME419) to 34.33±0.59 (Obasanjo2), 26.95±0.46 (Fallowed soil) to 29.22±0.46 (NPK 15:15:15), and from 25.95±0.37 (year two) to 29.96±0.37 (year one), respectively. Planting improved varieties in a NPK 15:15:15 amended soil at 400 kg/ha enhances cassava output, thus recommended.

Cassava ( Manihot esculenta Crantz) is an important crop for humans due to its staple and industrial values. Currently the demand is more than the supply as the current output falls below the expected. This necessitated the breeding of superior genotypes that are high yielding. These superior genotypes also requires a fertile soil for optimum production. However, this has been primarily achieved through the application of inorganic manures. It is then important to evaluate four newly released cassava varieties in an organically enriched soil relative to the local best variety. Four newly released cassava varieties, Hope, Obasanjo2, Baba 70, and Game changer, and one Local Best (LB) was planted in 5-years fallowed farm lands at three plots (A, B and C) for 2 seasons. It was a three-way factorial (5-varieties*3-farms*2-seasons) arranged in a randomized complete block design and replicated three times. Data were taken on the Fresh Tuber Weight (FTW) and Stem Height (SH) per variety, and pre and post soil status. Data were analyzed using analysis of variance, while differences in varietal means were separated using least significant differences at 5% level of significance. The FTW and SH differed significantly across varieties, years and interaction between variety, farms and year, and ranged from 19.2±0.5 (LB) to 41.0±0.5 (Obasanjo2), 32.1±0.4 (farm C) to 34.1±0.4 (farm A), 30.4±0.3 (year two) to 35.0±0.3 (year one), and the interactions between variety and year, farms and year, and variety, year and farms were significant. The soil macro and micro elements declined in the post relative to the pre status. The yield obtained from the improved varieties almost doubled the local best and yield declined in the second season.