Transgenerational Stress Memory Impacts Seed Quality and Early Development of Peanut (Arachis hypogaea L.).

Increases in the duration and severity of drought events are threatening water resources across the U.S. and, consequently, the resources utilized for agriculture are being increasingly scrutinized and criticized. Primed acclimation (PA) is a water-saving irrigation management strategy that can enhance the ability of the crop to respond to drought through exposure to mild or moderate water deficits during early development. Peanut generally responds positively to PA within a single season and yield maintenance under drought conditions has been achieved through this strategy. However, preliminary studies suggest that peanuts may develop a ‘memory’ of PA water deficits that can persist in subsequent generations, potentially through epigenetic mechanisms. Therefore, the primary objective of this study was to better characterize the impacts of this transgenerational stress memory (TSM) on seed quality and vigor. Fully mature seeds were collected from field-grown plants of five peanut varieties that were subjected to two irrigation treatments: fully irrigated (FI) (receiving 1.9 cm per irrigation event) and PA (receiving 60% of FI until the time of midbloom and 100% of FI, thereafter). The two seed groups collected from these disparate parental sources represented two treatments: 1) offspring from non-stressed plants (ONP; FI treated parents); and 2) offspring from stressed plants (OSP; PA treated parents). Seeds were grown in rhizotron tubes in a growth chamber for 12 days and parameters of early root development were measured. Additionally, germination and seed vigor were tested using traditional methods. Results indicate that impacts of TSM vary by cultivar: in some cultivars OSP had greater root growth as measured by total root length at 12 days than ONP, while in other cultivars the opposite was true; or for a few cultivars there was no difference in root growth between OSP and ONP. The implication of these results is that prior stress history of the parental generation can have lasting and meaningful impacts on the performance of the subsequent generation. This could require more strategic irrigation management to account for the potential impact of TSM on seed quality, vigor and perhaps other traits in a given variety.