Enhancing drought resilience in Persian walnut genotypes: Insights from photosynthetic dynamics and phenotypic analysis
نویسندگان
1 Department of Horticulture, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran; Department of Horticulture, College of Aburaihan, University of Tehran, Tehran, Iran.
2 Department of Horticulture, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
3 Department of Horticulture, College of Aburaihan, University of Tehran, Tehran, Iran
4 Department of Horticulture, College of Aburaihan, University of Tehran, Tehran, Iran
doi
10.22034/jppb.2025.68929.1376چکیده
Objective: The Persian walnut (Juglans regia L.), known for its notable sensitivity to drought stress, exhibits considerable genetic diversity within Iran. This genetic variability provides a valuable resource for developing and selecting drought-tolerant rootstocks.Methods: This study investigates the effects of water withholding on 115 walnut families from various climatic zones in Khorasan Razavi province, Iran, by analyzing polyphasic fast chlorophyll a fluorescence induction (OJIP), relative water content (RWC), and chlorophyll index (SPAD).Results: We observed reductions in electron transport flux per reaction center (ET0/RC), relative maximal variable fluorescence (FM/F0), maximum quantum efficiency of PSII (FV/FM), quantum yield of electron transport (Phi-E0), and the performance index (PI-ABS) in response to drought stress. In contrast, increases were observed in dissipated energy flux (DI0/RC), quantum yield of energy dissipation (Phi-D0), and specific energy fluxes per reaction center for energy absorption (ABS/RC), which are associated with photo-inhibition in plants subjected to water withholding. Using drought tolerance assessments and principal component analysis, we tentatively categorized the 115 walnut families into sensitive, tolerant, and moderately tolerant groups. Tolerant families, such as G107, B31, B66, B68, and B142, exhibited less variation in most traits from normal to drought-stress conditions, compared to sensitive and moderately tolerant families.Conclusion: Our findings highlight the effectiveness of chlorophyll fluorescence characteristics, RWC, and SPAD for the rapid identification of drought-tolerant genotypes.
