Germination of Diverse Chile Peppers (Capsicum spp.) Under Simulated Drought Conditions.

Evaluating whole plant responses to drought in wild and domesticated germplasm through environmental manipulation experiments can be expensive, time consuming, and challenging.  Responses vary based on plant development stage, drought severity, as well as the avoidance or tolerance mechanisms employed.  Therefore, it is necessary to study the effects of drought at individual development stages.  Early drought stress can restrict emergence and early seedling growth. Thus, in areas where water is only available for a short amount of time, rapid germination leading to earlier plant establishment may be beneficial. We studied the response to osmotic stress of 138 diverse chile pepper genotypes collected in southern Mexico, and regenerated in the greenhouse. Drought stress was simulated using four concentrations of polyethylene glycol (PEG): 0, 10, 15 and 20%. For evaluation, germplasm was grouped into five regions of origin, based on distinct precipitation and temperature trends. Overall, delayed germination was observed at 20% concentration PEG. Additionally, distinct germination patterns were observed based on the region of origin. Germplasm from wetter western Oaxaca had a faster rate of germination than germplasm collected from hotter and drier areas, including eastern coastal Oaxaca. Future work on this project will include further evaluation of germination patterns, phenotyping of physiological and morphological traits associated with drought resistance, and association of observed phenotypes with genotyping-by-sequencing (GBS) data and potential evapotranspiration based drought indices.