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Optimal nitrogen availability is necessary to keep high photosynthetic efficiency and in consequence, good physiological condition and growth of plants. In order to examine the effect of N nutrition on photosynthetic apparatus performance we used the chlorophyll a fluorescence (ChF) technique in two differing Actinidia cultivars and we aimed to select the most reliable ChF parameters showing N deficiency. The 4-years-old specimens growing on an experimental plantation were treated with three differing N doses and ChF data were collected during two years. The results showed that PSII performance indices, performance index on the absorption basis and total performance index, are useful to detect the overall decrease in photosynthetic apparatus vitality. Efficiency of electron movement beyond QA into the electron transport chain was more susceptible to different N nutritions than maximum quantum efficiency, while a pool of QA reducing reaction centres per PSII antenna chlorophyll, RC/ABS, and a number of QA reducing reaction centres per cross section of a sample, RC/CS0, were the best indicators of N deficiency.

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Actinidia arguta (Siebold et Zucc.) Planch. ex Miq. is functionally a cryptic dioecious plant and successful pollination is crucial for achieving high quality fruit. The extent and bases of morphological variability in female genotypes have been well studied, but here we focus on the males. Mature plants of seven male A. arguta genotypes were studied in 2016 and 2017 during which a suite of phenological and morphological features was measured on ten randomly chosen one-year-old canes on each plant. This analysis was complemented by two other, specialized measures potentially related to pollination efficiency, namely pollen quality, and quantity. The time of bud break was similar each year across all genotypes and the pollen quality was uniformly very high (viability – 95.0–99.9% and germination – 89.0–97.3%). However, the ten genotypes exhibited high variability in both the number of flowers per inflorescence and pollen quantity, indicating marked differences in their flowering potential and efficiency as pollinizers. The male kiwiberry indicators developed in this study – flowering potential and pollen efficiency, appear to be effective tools for the comparative evaluation of male A. arguta genotypes.

Kiwiberry (Actinidia arguta) is dioecious species which is now commercially grown in several countries worldwide. A study was conducted to determine the influence of five pollen sources derived from A. arguta (three cultivars), A. arguta var. purpurea ‘Rot’ and A. chinensis var. deliciosa ‘Tomuri’ on fruit and seed characteristics for three female A. arguta cultivars. Average fruit weight and biochemical features—fruit total phenolic concentration (TPC), ascorbate (ASC), pigments, total antioxidant activity and seed proteins profile were evaluated. TPC was determined using the Folin–Ciocalteu reagent assay. ASC, individual phenolic compounds and pigments composition were analysed using HPLC technique. Seed protein composition was analysed based on SDS-PAGE. Fruit phenolic and dry matter contents were influenced to a large degree by pollen sources while ASC content did not. The type of male and female parents used in the study were found to have a considerable effect on these parameters. The biggest differences in fruit phytocompound contents were found between female parents. The ‘Geneva’ cultivar showed the highest concentration of the most bioactive compounds tested. Four phenolic acids and five flavonoids were present in the highest concentrations in tested kiwiberry fruit. Actinidia chinensis var. deliciosa ‘Tomuri’ pollen clearly modified the seed protein spectrum with a 17 and 23 kDa protein. The obtained results indicate that to achieve desired fruit biochemical characteristics, the pollen source (male vines) should be selected individually for particular female cultivars, especially in the case of polyphenol content. Our findings suggest that not only A. arguta but also A. arguta var. purpurea and A. chinensis var. deliciosa ‘Tomuri’ males may be suitable as pollinizers for kiwiberry fruit production.