RT info:eu-repo/semantics/article T1 δ15N as a cultivar selection tool for differentiating alfalfa varieties under biosaline conditions. A1 Díaz Peña, Francisco Javier A1 Grattan, S. R. A1 Reyes, J. A. A1 Jiménez, C. A1 Tejedor, M. A1 González Rodríguez, A. M. K1 Medicago sativa K1 Biosaline agriculture K1 Stable isotopes K1 Salinity tolerance K1 Isotope composition AB Aims The potential of “biosaline agriculture” relies on easy-to-apply tools to select plant genotypes that are best adapted to saline conditions. We aimed to determine the effects of salinity-sodicity on the functional response of alfalfa varieties by evaluating instantaneous vs integrated plant-based measurements for the selection of alfalfa cultivars in biosaline agriculture. Methods Functional responses of three alfalfa varieties were evaluated in a greenhouse study under different saline-sodic conditions. Physiological parameters included instantaneous (gas exchange and chlorophyll fluorescence) vs time-integrated (carbon isotope discrimination -Δ13C- and nitrogen isotope composition -δ15N-; specific leaf weight and chlorophyll content) measurements. Results From all assessed physiological traits, only δ15N was able to effectively discriminate among genotypes WL656HQ, PGI908S and SW8421S, and showed the highest correlation with biomass production at all experimental stages. On average, the δ15N increased by a factor of 3.3 as salinity increased from the non-saline control treatment (ECiw ~ 0.4 dS m−1) to the highest salinity level (ECiw ~ 10.0 dS m−1) indicating that biological N fixation was significantly limited by salinity.Specific leaf weight was also significantly correlated with dry matter although to a much lesser extent thanwas δ15N. Conclusions δ15N was found to be the best proxy for assessing alfalfa varieties for their adaptation potential in saline conditions. This parameter was able to discriminate alfalfa’s functional response within a narrow range of irrigation water salinity. δ15N was also capable ofdifferentiating between alfalfa varieties classified as tolerantto salinity defined at a particular plant growth stage, making this an excellent tool for genotypic selection. YR 2020 FD 2020 LK http://riull.ull.es/xmlui/handle/915/35941 UL http://riull.ull.es/xmlui/handle/915/35941 LA en NO https://doi.org/10.1007/s11104-020-04652-8 DS Repositorio institucional de la Universidad de La Laguna RD 10-may-2024