Exploring the cold tolerance capacity of USDA pea (Pisum sativum L.) collections

Winter pea (Pisum sativum L.) is a commonly grown winter annual legume cover crop in the US due to its nitrogen-fixing capabilities, effective weed suppression, and several other ecosystem services. Despite the availability of winter-hardy cultivars, inconsistent winter survival remains a challenge, particularly in northern regions. To address this, we investigated the temperature thresholds for cold tolerance and freeze-thaw tolerance using germplasm from the USDA Pea Single Plant Plus Collection (PSPPC), Pea Single Plant (PSP), cover crop breeding network (CCB) pea breeding lines, and ‘Wyowinter’ cultivar as a control in a thermogradient table. Plants were exposed to two freeze-thaw cycles with the lowest soil temperatures of -7°C and -14°C in the first and second cycles, respectively. All genetic groups were severely injured in both cycles, but there were no complete deaths. Wyowinter had a significantly lower damage score and the least percentage of total plants damaged compared to other groups. However, there was no significant difference in ion leakage among groups. Moreover, there was large variation in damage levels among plants within each group, suggesting different levels of cold tolerance among genotypes. For future studies, we will conduct individual evaluations of germplasms within our genetic groups to explore genetic variation for cold tolerance and identify hardier genotypes. Furthermore, we will stress plants to lower temperatures than currently tested and conduct experiments in a growth chamber where temperature conditions are more similar to field conditions compared to the thermogradient table.

My summer experience at Cornell was immensely insightful and confirmed my decision to apply to graduate school. I loved going to the lab and being in an environment where I was constantly surrounded by other individuals conducting interesting research that has practical applications. During my experience, I learned to be more patient and adaptable due to the nature of how unpredictable plants can be. I gained more confidence over the summer to be curious and say yes to more opportunities because of how welcoming the community is. I loved the data analysis and visualization component of my research, getting lost for hours manipulating code to elucidate different relationships within our experiment. I plan to integrate my passion for ecological research with my statistical background into my graduate studies and feel more prepared after this internship for what will come after my undergraduate experience.