Document Type : original paper
Authors
1
Department of Horticultural Sciences, University of Guilan, Rasht, Iran
2
Department of Horticulture, Faculty of Agriculture, University of Guilan
3
Department of Soil Sciences, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
4
Department of Horticultural Sciences, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
10.22069/jopp.2026.25052.3365
Abstract
Background and Objectives: Waterlogging is one of the most important abiotic stresses affecting kiwifruit, as soil saturation restricts oxygen availability in the root zone, thereby impairing plant growth, nutrient uptake, and photosynthesis. Kiwifruit is particularly susceptible to waterlogging because of its shallow, fleshy root system. The degree of tolerance depends on the genetic background, rootstock, and duration of flooding. Therefore, the aim of this study was to compare the responses of five kiwifruit genotypes including 'Hayward', 'Bruno', A.valvata, 'Hayward' grafted onto 'Bruno' rootstock, and a red-fleshed cultivar grafted onto 'Bruno' rootstock, under four levels of waterlogging stress, and to evaluate their differences in growth traits, photosynthetic pigments, and leaf nutrient concentrations.
Materials and Methods: The experiment was conducted as a factorial experiment based on a completely randomized design (CRD) with four replications. Plants were exposed to four waterlogging durations (3, 7, 11, and 15 days). Sixteen pots of each genotype were selected and subjected to the waterlogging treatments. The pots were placed in plastic containers (76 × 62 × 30 cm) filled with water so that the water level remained 1–2 cm above the soil surface. Water was replenished whenever necessary to maintain complete waterlogging throughout the treatment period. Immediately after each waterlogging duration, leaf and root samples were collected for physiological, biochemical, and nutritional analyses.
Results:: The results showed that cultivar and waterlogging duration had significant effects on most of the studied traits. Increasing the waterlogging duration from 3 to 15 days the mean shoot diameter 28.9% reduction), leaf number 26.3%, and leaf dry matter content 15.5% decreased. Chlorophyll a content also decreased from 1.60 to 1.44 mg g⁻¹ fresh weight, whereas MDA content increased from 4.15 to 4.75 μmol g⁻¹ fresh weight. Nutrient concentrations declined with increasing waterlogging duration; mean concentrations of nitrogen, potassium, calcium, magnesium, iron, zinc, and manganese decreased by 4.4, 7.9, 26.0, 22.4, 12.3, 34.7, and 14.8%, respectively, compared with 3 days of waterlogging. Among the genotypes and graft combinations, A.valvata maintained higher values for most growth traits, photosynthetic pigments, and nutritional parameters, whereas ‘Hayward’ exhibited the greatest decline. At 15 days of waterlogging, nitrogen concentration in A.valvata and ‘Hayward’ was 6.30 and 5.21 g 100 g⁻¹ dry matter, respectively, while their iron concentrations were 166.90 and 100.05 mg kg⁻¹, respectively. ‘Bruno’, ‘Hayward/Bruno’, and ‘Red-fleshed/Bruno’ generally showed intermediate responses. Overall, the greater stability of growth traits and maintenance of nutrient concentrations in ‘Valvata’ compared with the other genotypes indicated its greater tolerance to reduced oxygen availability in the root zone under waterlogged conditions.
Conclusions: Overall, waterlogging stress markedly reduced plant growth, photosynthetic pigments, and nutrient uptake, particularly in susceptible genotypes such as 'Hayward', resulting in severe growth inhibition. In contrast, more tolerant genotypes, especially A.valvata, were able to mitigate these adverse effects more effectively. Therefore, the use of waterlogging-tolerant genotypes and rootstocks represents an effective strategy for reducing flooding damage in kiwifruit orchards, particularly in regions prone to soil waterlogging.
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