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.

Yam is an important staple in sub-Saharan Africa, but the availability of quality seed yam is majorly constrained by the low propagation ratio. This is because the propagating explant is limited to the tuber and nodal parts as yam rarely flowers. There are several reports of the use of somatic embryogenesis (SE) in the rapid propagation of different crop species and as a regenerative pathway in plant genetic engineering. However, SE deployment in yam is still at the protocol development stage. This review thus exploits the status of SE application in improving the yam propagation rate. This article reviews the potential of the various yam propagation techniques in rapidly multiplying disease-free yam with their propagating explants. The advantages SE offers are rapidly propagating yam, the factors to consider in the protocol optimization of SE application in rapidly multiplying different yam varieties, and as a platform for full utilization of genetic engineering in yam. The findings so far show that SE potentially offers a faster rate of propagating yam varieties. However, due to the differences in varietal endogenous hormonal and gene products, response to SE in yam is constrained by varietal specificity. Hence, the applicability of SE in yam is still at the protocol development state. This review, thus, presents the need for more research efforts to elucidate the molecular and phytochemical controlling mechanisms of SE in yam to improve the yam multiplication rate and lay an efficient platform for the exploitation of other biotechnological advancements in improving yam species.

The primary goal of this study was to compare the multiplication rates of yam varieties propagated through organogenesis and somatic embryogenesis (SE). Callus was induced from axillary bud explants of three genotypes of Dioscorea rotundata (Asiedu, Ekiti2a, and Kpamyo) and two genotypes of Dioscorea alata (Swaswa and TDa2014) cultured in Murashige and Skoog (MS) medium containing 9.1 µM 2,4-dichlorophenoxylacetic acid and 5.4 µM naphthaleneacetic acid. Plantlets were regenerated in MS containing 4.4 µM benzylaminopurine and 34 µM uniconazole-P through SE. Single-node cuttings of the five genotypes were grown in MS for 8 wk via organogenesis. The SE and organogenesis regenerants were acclimatized and potted in a 2 (propagation techniques (PTs)) × 5 (genotypes) factorial arranged in a completely randomized design (r = 10). The multiplication ratios (MR), number of tubers (NoT) of the SE, and organogenesis regenerants were collected and analyzed using ANOVA, and means were separated using DMRT (P ≤ 0.05). The SE and organogenesis MR ranged from 1:2 (TDa2014) to 1:8 (Asiedu) and 1:4 (Asiedu) to 1:5 (Ekiti2a and TDa2014), respectively. The NoT differed among genotypes, ranging from 1.15 ± 0.49 (Swaswa) to 2.45 ± 1.39 (Asiedu), and between PTs, ranging from 1.42 ± 0.70 (SE) to 1.86 ± 1.11 (organogenesis). The optimum propagation pathway was genotype-specific.

Yam is a staple crop in Africa that is constrained by its low multiplication rate. This results in a short supply of seed tubers, which is a challenge to increased production. This study assessed the influence of different minisett weights (10, 20, 30, 40, and 50 g) on tuber production and seed categorization in twelve Dioscorea rotundata and four Dioscorea alata varieties over two planting seasons in a Randomized Complete Block Design (r = 3). The yield parameters were collected and analyzed using ANOVA. The effects of varieties, the minisett weight (SW), and the variety × SW interaction were significant for the proportion of setts that produced seed tubers and ranged from 40.2 ± 5.0% (50 g) to 56.4 ± 5.0% (10 g) in 2013, from 46.4 ± 0.8% (40 g) to 60.5 ± 0.8% (30 g) in 2014, from 23% (TDa00/00194, 30 g) to 93.7% (Ojuyawo, 10 g) in 2013, and from 39.7% (TDa00/00194, 30 g) to 100% (TDr89/02665, 20 g) in 2014. The 10 g and 30 g produced more seed yam in 2013 and 2014, respectively, while 50 g produced more ware yam sizes (>300 g) and is thus recommended to farmers for intended yam production category. D. rotundata varieties produced a higher proportion of seed yam, while D. alata varieties produced are a higher proportion of yams above seed class.

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.

Exopolysaccharides-EPS are long-chain biopolymer with branched, recurring unit of sugars and non-carbohydrate constituents connected to exterior of cells. Rhizobial, a legume nodulating organism is capable of producing EPS. This study investigated the characteristics’ of some Rhizobium EPS and their effects in shelf life extension of some Musa spp. Rhizobial-EPS was produced using yeast extract mineral medium purified by standard methods. The EPS was characterized to determine functional group, thermal stability, chemical compounds and the monosaccharide component using Fourier Transform Infra-red, Spectroscopy, thermogravimetric Analysis (TGA), Gas Chromatography–Mass Spectrometry and HPLC and their bio-preservative property on post-harvest quality of plantain and different banana was done. The Rhizobial-EPS functional groups were hydroxyl, carboxyl, amine, methyl and ethers associated with polysaccharides. Pentadecanoic acid, octadecanoic acid, oleic acid and heptacosanoic acid, and varied concentration of monosaccharides were detected in the exopolysaccharides. The TGA of the EPS shows a constant loss in weight with two quasi-sharp alterations and almost steady plateau. The EPS coated samples had the lowest weight loss across the samples and as such edible coating was effective in delaying weight loss. The weight loss of Musa paradisiaca (plantain) coated with (EPSA obtained from USDA 110), (EPSB USDA 532C) and (EPSC S2) at the first day were 314 and 314.5g. The initial weight loss of coated and uncoated Musa sp. (Apple Banana), Musa acuminata (Lady Finger), and Musa balbisiana (Cooking Banana), ranged from 72 – 72.7g, 96 – 97g and 95 – 98g respectively. The total sugar of EPS Coated Musa sp. ranges from 0.381 – 0.528mg/L, 0.392 – 0.576 mg/L and 0.41 – 0.598 mg/L at days 1, 2 and 3 respectively. The highest Titratable acidity and pH was observed in EPS coated sample. The results obtained from this study proves that EPS solution is a valuable product for fruit preservation and viable for commercial applications.