Morphological variations of white yam (Dioscorea rotundata) treated with different concentrations of ethyl methane sulfonate

Abstract

White yam (Dioscorea rotundata) is an essential staple crop in many tropical regions, contributing immensely to food security and livelihoods for millions of people. However, its cultivation is limited by factors such as low yield and lack of genetic diversity. To address these challenges, this study investigated the response of white yam to different concentrations and timings of Ethyl methane sulfonate (EMS), a chemical mutagen used to induce genetic variation. Minitubers obtained from single nodal vine cuttings with a leaf each previously treated with 0.5% and 1.0% concentrations with exposure durations of 1.0, 1.5, 2.0, and 2.5 hours were planted and allowed to grow into mother plants. Two months later, single vine nodes were carefully cut from the mother plants and planted directly into sterilized topsoil within a controlled environment, and morphological variations were evaluated using ANOVA (SAS 9.0 version), and differences in means were separated at P≤0.05 using LSD. At eight weeks, yam seedlings with EMS 1% treatment for 1 hour had the highest number of leaves (7.22 ± 0.53) and the longest vine (49.41 ± 3.60 cm) and produced the highest number of nodes count (7.19 ± 0.53), while the fewest leaves (3.88 ± 0.53) and the shortest vine (29.84 ± 3.60 cm) were recorded for the control. The highest leaf area (43.07 ± 1.84 cm²) was recorded for the seedlings treated with 0.5% for 2 hrs., and the lowest leaf area (30.27 ± 1.84 cm²) was recorded for 0.5% at 2.5 hrs. The largest tuber weight was obtained with EMS 1% for 1 hour (21.95 ± 4.89 g). The results suggest that EMS 1% treatment for 1 hour can significantly improve yam productivity and yield.