This research article was published in Scientific Reports by Nature Research. It is available via DOI: https://doi.org/10.1038/s41598-020-58035-1Effective phenotyping for drought resistance is a pre-requisite for identification of modest crop
varieties for farmers. For neglected and underutilized crops such as Solanum aethiopicum Shum
group, no drought screening protocol based on rigorous iterations has been documented. A split-plot
nested treatment structure was arranged in an experiment to identify growth stage-specific watering
thresholds for this crop. Three plant growth stages (main plot; seedling, vegetative and flowering),
watering regime at plant growth stage (2 regimes; well-watered and drought stressed) and day since
last watering at plant growth stage were evaluated for soil moisture content (SMC), leaf wilting
score (LWS), number of green leaves per plant (LPP) and leaf blade width (LBW). Highly significant
differences (p < 0.001) were found at the different plant growth stages, watering regime (WR) within
plant growth stage, and day within WR and plant growth stage. Under drought stress treatment, SMC
declined exponentially at each stage. The earliest leaf wilting, reduction in LPP and LBW were generally
observed at flowering followed by vegetative and slowest at the seedling stage. For future effective
drought phenotyping studies in S. aethiopicum Shum and related crops, we recommend setting
minimum drought stress treatments below 18% SMC at which the LWS is ≥2 at the vegetativeThis study was support by The World Academy of Sciences (TWAS), Grant Number 16-163 RG/BIO/AF/AC_I – FR3240293342 towards equipment for the project titled “Phenotyping water use efficiency in Solanum aethiopicum, Shum Group”. Co-funding was generous provided by the European Union through Forum for Agricultural Research in Africa (FARA) in a project ‘Enhancing nutrition security and incomes through adding value to indigenous vegetables in East and Central Uganda’ (FARA/PAEPARD-CRFII)
