The interspecific breeding of yams (Dioscorea spp.) for superior traits is hindered by the dioecious nature of their flowers and low flowering frequency, despite the potential of wild yams to improve related cultivated varieties. However, the genetic variability of these wild yam species has yet to be fully explored. This study investigated the genetic variability and heritability estimates for multi-trait selection of hybrids derived from crosses between two wild yam species, Dioscorea abyssinica and Dioscorea praehensilis. Field experiment was conducted on 65 hybrids using a partially replicated block design. With standard descriptors, data were collected on phenotypic traits, including stem length, internode, plant vigour, tuber length, tuber weight, tuber width, tuber thorniness, and tuber surface cracks. Heritability, genetic advance and variance components were estimated to quantify the genetic contribution to trait variability. Analysis of variance identified significant differences (p=0.00) among hybrids and high genetic variability was observed in phenotypic traits assessed, with tuber weight showing the highest genotypic (104%) and phenotypic (127%) variances. Heritability estimates suggested strong selection potential for stem length (74%), tuber weight (67%) and tuber hairiness (65%), while tuber shape (7%) and tuber width (9%) showed low genetic potential. Multi-trait Genotype Ideotype Distance Index (MGIDI) analysis further identified 8 high-performing wild yam hybrid accessions (TDabp2101010, TDabp2101013, TDabp2101030, TDabp2101042, TDabp2101046, TDabp2101050, TDabp2101052, and TDabp2101055). These findings demonstrate the potential of wild yam hybrids for trait introgression, thereby paving way for the development of new yam cultivars and providing valuable insights for yam improvement programs.

Yam (Dioscorea spp.) is an important staple crop in West Africa, and genetic diversity plays a crucial role in its improvement. The complexity of ploidy levels and chromosomal instability in yam species presents a significant challenge to breeding efforts. Therefore, this study aimed to investigate chromosomal variation in Dioscorea spp. from parental lines to F₂ progenies to provide crucial information for optimising yam breeding programs and improving hybrid selection processes. A total of 67 accessions, including parental lines (Dioscorea praehensilis, D. abyssinica, and D. rotundata), their F₁ and F₂ progenies, were assessed. Chromosome counts were conducted on mitotic cells using the squash technique and FLP orcein staining. The number of chromosomes and abnormalities were recorded, and data were analysed using descriptive statistics. Among the 15 parental lines (D. praehensilis, D. abyssinica, and D. rotundata) assessed, 12 had diploid chromosome counts of 2n = 2x = 40, indicating chromosomal stability. Chromosomal abnormalities, including aneuploidy (2n = 34, 2n = 37, and 2n = 35), were observed in three parental accessions, accounting for a 19.05% abnormality. Interestingly, of the 30 F₁ hybrids, 10 exhibited 2n = 20 (a putative haploid chromosome number), while the others showed high chromosomal variation, with chromosome counts ranging from 2n = 18 to 2n = 33, resulting in a 66.67% abnormality rate. In contrast, 14 of 22 F₂ progenies exhibited increased chromosomal stability, with a higher proportion of diploid counts (2n = 2x = 40) aligning with those of the parental lines. The abnormality rate dropped to 33.52% in F₂ progenies, indicating that chromosomal balance was restored through selfing and backcrossing. This study demonstrates that while interspecific hybridisation induces chromosomal instability in F₁ yam hybrids, subsequent selfing and backcrossing with D. rotundata can restore diploid stability in F₂ progenies. The findings offer cytogenetic insights vital for optimising hybrid selection and developing genetically stable yam cultivars for breeding programmes.

Macauba ( Acrocomia spp.) is an underutilised palm, native to Brazil and other tropical regions of the Americas, with substantial potential for vegetable oil and bioenergy production. However, its long juvenile phase delays the identification of promising parents and hybrid combinations. This study characterised the early vegetative performance of 60 individual macauba hybrids derived from intraspecific Acrocomia aculeata crosses and an interspecific A. aculeata × Acrocomia totai cross. Seventeen traits related to plant architecture, leaf morphology and biomass were evaluated over 2 years (2023–2024) using a mixed model fitted by restricted maximum likelihood, with the year as a fixed effect and accession as a random effect. Repeatability, predicted accession effects, trait correlations, principal component analysis, hierarchical clustering and a composite vigour index were also examined. Considerable phenotypic and persistent among‐plant variation was observed, where the number of fallen leaves showed the highest phenotypic and among‐plant coefficients of variation (78.2% and 55.9%, respectively). Repeatability was moderate for all traits ( R = 0.42–0.52), except central pinna width ( R = 0.11). Fresh mass of pinnae was strongly correlated with dry mass of pinnae ( r = 0.90) and moderately correlated with other vegetative and biomass‐related traits, including central pinna length ( r = 0.67), indicating that fresh pinna mass may serve as a practical proxy for pinna dry mass. The first two principal components explained 61.9% of the multivariate variation, driven mainly by biomass and structural traits. The vigour index identified 10 putative hybrid candidates, with H19‐14, H20‐5 and H17‐9 receiving the highest scores. These outcomes provide useful phenotypic information for early screening in macauba, although the selected plants require further validation through replicated, multiyear evaluations that include fruit and oil‐production traits. This work offers a practical starting point for accelerating early‐stage selection in macauba breeding to enhance its productivity as a sustainable bioenergy crop.