Seed size is an important yield and quality-determining trait in higher plants and is also crucial to their evolutionary fitness. In African yam bean (AYB), seed size varies widely among different accessions. However, the genetic basis of such variation has not been adequately documented. A genome-wide marker-trait association study was conducted to identify genomic regions associated with four seed size traits (seed length, seed width, seed thickness, and 100-seed weight) in a panel of 195 AYB accessions. A total of 5416 SNP markers were generated from the diversity array technology sequence (DArTseq) genotype-by-sequencing (GBS)- approach, in which 2491 SNPs were retained after SNP quality control and used for marker-trait association analysis. Significant phenotypic variation was observed for the traits. Broad-sense heritability ranged from 50.0% (seed width) to 66.4% (seed length). The relationships among the traits were positive and significant. Genome-wide association study (GWAS) using the general linear model (GLM) and the mixed linear model (MLM) approaches identified 12 SNP markers significantly associated with seed size traits across the six test environments. The 12 makers explained 6.5–10.8% of the phenotypic variation. Two markers (29420334|F|0-52:C>G-52:C>G and 29420736|F|0-57:G>T-57:G>T) with pleiotropic effects associated with seed width and seed thickness were found. A candidate gene search identified five significant markers (100026424|F|0-37:C>T-37:C>T, 100041049|F|0-42:G>C-42:G>C, 100034480|F|0-31:C>A-31:C>A, 29420365|F|0-55:C>G-55:C>G, and 29420736|F|0-57:G>T-57:G>T) located close to 43 putative genes whose encoding protein products are known to regulate seed size traits. This study revealed significant makers not previously reported for seed size in AYB and could provide useful information for genomic-assisted breeding in AYB.

Landraces are repositories for potential beneficial traits which could be used to develop varieties with enhanced qualities. Optimal utilization of the available large collection of landraces of African yam bean (AYB) presently conserved at the Genetic Resource Center, International Institute of Tropical Agriculture, Ibadan (GRC-IITA), requires an assessment of the magnitude and nature of genetic diversity within the germplasm. One hundred and ninety-six AYB accessions were evaluated during the 2018 and 2019 cropping seasons in three agro-ecologies of Nigeria, using a 14 × 14 triple lattice design. The accessions were assessed for fourteen agronomic traits. Accession, environment, and accession × environment interaction effects were significant (p < 0.05) for all the traits. Variances due to environment and accession × environment interaction were higher than the genotypic variances. Similarly, estimates of phenotypic coefficient of variation (PCV) were higher than genotypic coefficient of variation (GCV) for all traits. Broad-sense heritability ranged from 17.1% (days to maturity) to 66.4% (seed length). Seed yield per plant had positive significant genotypic correlation with all the studied traits, except pod length and seed length. The first three principal components accounted for 59.7% of the total variation among the accessions and comprised of the 14 traits. Five major clusters were delineated based on phenotypic characteristics. Genetic variation was present among the AYB accessions, and these results will be useful for setting breeding goals and conservation approaches.

Mississippi soybean [Glycine max (L.) Mer.] producers are under pressure to plant as much land as possible within narrow planting windows. The 5‐year average planting progress is 45% of the total at the end of the optimal soybean planting window. New metering and seed delivery technology claims faster planting without sacrificing singulation, stand, or yield, but these tools need to be validated before recommendation. This study aimed to quantify soybean response to planting speeds using a precision planter (John Deere MaxEmerge 2 row units retrofitted with Ag Leader SureSpeed and SureForce) and a mechanical planter (John Deere 1700 ground‐driven mechanical planter equipped with eSet meters) for a total of 7 site‐years across Mississippi. In 2022, both planters were evaluated at four actual ground speeds of 7.9, 10.8, 13.5, and 16.4 km h⁻¹ in a 2 × 4 factorial design. The experimental design was modified in 2023, where the mechanical planter served as the current farmer practice check at 9.7 km h⁻¹and the precision planter speeds were 9.7, 14.5, and 17.7 km h⁻¹ at research station sites and 9.7 and 14.5 km h⁻¹ at an on‐farm site. Across sites, increased planting speed generally increased plant spacing, in‐row spacing variability, and decreased plant population. However, increased speed did not affect soybean yield. The precision planter at 17.7 km h⁻¹ was no different from the mechanical planter in terms of soybean plant population, spacing, and yield in 2023. Results suggest soybean producers can plant soybean at 17.7 km h⁻¹ without compromising yield.

Timely planting and uniform stands are prerequisites for optimal corn ( Zea mays L.) production. However, frequent rainfall often limits corn acreage planted in the southeast region of the United States. Planting faster might offer a potential solution as new technology claims up to 19 km h ⁻¹ planting speeds without sacrificing seed singulation or yield. The objective of this study was to evaluate corn response to varying planting speeds in Mississippi. Trials were arranged as a randomized complete block design during the 2023 and 2024 cropping seasons. A precision planter (John Deere bar and MaxEmerge 2 row units retrofitted with Ag Leader SureSpeed and SureForce) was tested at 9.7, 14.5, and 17.7 km h ⁻¹ actual ground speeds. A mechanical planter (John Deere 1700 ground‐driven planter equipped with eSet meters) at 9.7 km h ⁻¹ was used as a standard check. Corn hybrid DKC 70‐27 was planted at 81,800 and 85,000 seeds ha ⁻¹ in 2023 and 2024, respectively. In both seasons, increased planting speed generally lowered plant population and quality of seed placement with increased skips and spacing variability. Planting at 14.5 km h ⁻¹ optimized precision and reduced multiples using the precision planter. Moreover, planting speed beyond 14.5 km h ⁻¹ did not affect corn yield. The precision planter at 17.7 km h ⁻¹ exhibited improved performance over the mechanical planter at 9.7 km h ⁻¹ , particularly in maintaining lower miss and multiple indices. Using this technology, Mississippi corn producers can plant more land within the critical planting window at higher speeds without affecting yield.

African yam bean (AYB) is an underutilized legume with significant potential for food security in sub-Saharan Africa, yet limited research exists on optimizing its seed yield through selective breeding. In this study, the seed yield (SY) performance and relative importance of some yield-related traits on SY in AYB were assessed. One hundred and ninety-six accessions of AYB were evaluated for 2 years in three agro-ecologies of Nigeria. The experimental design was a 14 × 14 lattice design with three replicates. Data were recorded on SY and 13 SY-related traits. Positive significant genotypic correlations were found between SY and 11 of these traits. Pod length (PL) had a negative significant relationship (r_g = −0.44**) with SY. Path coefficient analysis identified days to maturity (DM), pod weight (PW), shelling percentage (SP), number of seeds per pod (NSPD), 100-seed weight (HSW) and seed thickness (ST) as traits with positive direct effects on SY. The additive main effect and multiplicative interaction analysis revealed highly significant accession, environment, accession × environment interaction and interaction principal components effects for SY. Accessions TSs-119, TSs-101, 138A, TSs-4, TSs-157A and TSs-61 were identified as superior and stable, and should be considered for further breeding purposes. Selection criteria for improved SY in AYB should include DM, PW, SP, NSPD, HSW and ST. The identified stable, high-yielding accessions and key yield-related traits provide a framework for accelerating AYB improvement across diverse agro-ecologies.

Corn ( Zea mays L.) plant spacing and uniform growth are important, but increased planter speed and surface roughness may compromise seed placement uniformity by increasing planter component vibration. This study evaluated planting speed and downforce settings on planter component vibration, seed placement uniformity, and grain yield. Field trials were conducted over 4 site‐years (2024–2025) in Mississippi using a precision planter (John Deere MaxEmerge 2 row units retrofitted with Ag Leader SureSpeed and SureForce). Two actual planting speeds (7.7 and 15.5 km h ⁻¹ ), two downforce modes (dynamic and static), and three downforce settings (minimum, medium, and heavy) were evaluated in a 2 × 3 × 3 factorial laid in a randomized complete block design with four replications. Measurements included row‐unit vibration using three‐axis accelerometers, seed depth, plant population, spacing uniformity, seed placement quality indices, and grain yield. Planting speed was noted to be the only factor affecting row‐unit vibration, which increased from 12.5 to 16.0 m s ⁻² when speed doubled. Higher speed reduced plant population, seeding depth, multiples, and increased miss index by 54%. Heavy downforce produced optimal plant population followed by the medium and minimum settings. The influence of increased downforce settings disappears with increased planting speed. Static downforce mode improved seed depth consistency, whereas dynamic downforce offered better miss index control at higher speeds. Despite significant effects on stand establishment, grain yield was unaffected by any treatment. Therefore, results demonstrate that producers can prioritize planting speed to improve field efficiency without substantial yield penalties. However, appropriate downforce settings enhance stand establishment quality.