Search

Abstract The most widely cultivated species globally is Actinidia deliciosa cv. ‘Hayward’. However, in recent years, consumers have shown greater demand for new varieties with novel flesh colour, flavour and appearance in international markets. To meet these expectations, one breeding study was started in 2016 at the University of Guilan in Iran to develop new kiwifruit cultivars with superior characteristics. In this breeding program, 201 female and 534 male hybrid genotypes were obtained from combinations of six different parents using the controlled cross-breeding technique. The evaluations were carried out over three consecutive stages. In the first stage, 201 female hybrid genotypes and control (‘Golden’) were evaluated based on 25 phenological and pomological traits. In the second stage, hybrids passed the desired threshold values in 7 key attributes were selected. Sensory testing in the next stage evaluated these selected hybrid genotypes more. As a result of the first stage, 30 hybrid genotypes with fruit weight (90 ≥ g) were selected. Then, in the second stage, 21 hybrids that showed acceptable dry matter, hue angle, flesh firmness, soluble solid content, acidity, and ascorbic acid were selected. Finally, 13 hybrid genotypes received high scores in sensory testing, and just two hybrid genotypes represented a 100% of novelty with positive texture. These genotypes were selected as potential cultivar candidates. In future studies, fruit yield, disease/pest resistance, and post-harvest performance trials of the 13 selected candidates will be evaluated at different sites. Thus, the ones that give the best results will be introduced to kiwifruit growers.

Abstract Backround In recent years, with the increasing demand for seedless grape varieties that have lower production costs, are disease resistant/tolerant and require less chemical pesticides, the embryo recovery technique has begun to be used more in table grape breeding studies. However, the desired high success rate has not yet been achieved in these studies. Although there are different reasons for this, especially the grape varieties selected for cross-breeding and the timing of transferring the embryos to medium are among the most important reasons. In this study, focusing on these two important factors, the embryos obtained from different hybridization combinations were transferred to agar medium at different weeks for 4 years and the most successful combination and time were determined. In addition, seedless and large berry grape varieties and some seeded varieties that are resistant/tolerant to fungal diseases were selected as parents because they can provide resistance to disease infections in vitro and thus increase the success rate. Results The results obtained from the study showed that the selected variety and combination significantly affected the success rate in embryo rescue. Especially in combinations with the ‘Yalova Seedless’ variety as the female parent, more successful results were obtained compared to combinations of other varieties. When ‘Yalova Seedless’ variety was pollinated with pollen of ‘Red Globe’, ‘Muscat Bailey A’ and ‘Exalta’ varieties, more seedlings were obtained with the help of embryo rescue. The results obtained over four years showed that the best sampling time after pollination was the eighth week and then the seventh week. Conclusions According to the results obtained, it has been shown that the selected varieties and the sampling time significantly affect the success rate in embryo rescue studies. Therefore, higher success rates can be achieved in comprehensive breeding studies in which they will be included as pollinators, especially in different seeded varieties that are resistant to diseases and have larger berry size.

In this study, it was planned to identify the seedless genotypes by screening with molecular markers for early selection among the F1 genotypes obtained in the hybridization study. In addition, it was aimed to determine the appropriate sampling time by applying the embryo rescue technique for F1 genotypes obtained from these combinations in which seedless varieties were used as the female parent. When the conversion rates into plants were examined, 50% success was achieved in the Yalova Seedless X Glenora combination, while this rate was 62.5% in the Yalova Seedless X Philipp combination. In the study, F1 genotypes obtained from these were screened with the VvAGL11 marker. When the appropriate sampling times were examined, while the 8th week was prominent in the Yalova Seedless X Philipp combination, the best results were obtained from the samples taken at the 9th week in the Yalova Seedless X Glenora combination.

Climate changes occurring today require detailed research of the effects of increasing temperatures on photosynthesis in different species and cultivars. Temperature variability is a crucial determinant of the yield and quality of plants, particularly when high-temperature episodes coincide with their growth and fruit development. The effect of high temperature (HT) on higher plants primarily concerns photosynthetic functions, but the sensitivity of photosynthesis to high temperature is not well-understood in kiwifruits. In this study, we designed a new environmental monitoring system to evaluate the effects of environmental factors on the photosynthetic physiology of different kiwifruit species and cultivars. A significant positive correlation was determined between the main photosynthetic indices of kiwifruits, such as transpiration rate and net photosynthetic rate. The net photosynthetic rate of commercial kiwifruit cultivars was strongly inhibited when the temperature exceeded 44.5 °C, and the leaves of kiwifruits were irreversibly damaged when the temperature increased to 52 °C. Kiwifruit cultivars with different ploidy levels (diploid, tetraploid and hexaploid) were found to be sensitive to high temperature, whereas tetraploids had higher HT resistance and hexaploids had the highest net photosynthetic rate. Further research showed that the HT tolerance of kiwifruits existed not only between species but also among cultivars. A. eriantha had the highest net photosynthetic rate at more than 44.7 °C, but those of A. deliciosa and A. arguta declined sharply as the temperature exceeded 43.5 °C. As a result, it was determined that high temperatures have important effects on the photosynthetic activities of kiwifruit plants with different ploidy levels, and that these effects can significantly change their development according to how they differ among different species/cultivars.

The completed chloroplast genome sequence of Actinidia hemsleyana, collected from eastern China, was firstly determined using next-generation sequencing (NGS) and bioinformatic analysis. The length of cp genome was 156,845 bp, including a large single-copy (LSC) region of 88,666 bp and a small single-copy (SSC) region of 20,543 bp, which were separated by a pair of inverted repeats (IRs) of 23,818 bp. The cp genome contained 132 genes, including 83 protein-coding genes, 41 tRNA genes, and 8 rRNA genes. The overall GC content was 37.19%, whereas the corresponding values of the LSC, SSC, and IR regions were 35.46%, 31.09%, and 43.06%, respectively. Phylogenetic analysis based on whole cp genome sequences of 20 Actinidia species showed that A. hemsleyana has the closest relationship with A.latifolia.

Raisins have been widely consumed for many years all around the world, and different grape cultivars and drying techniques are used in their production. Recently, mechanical drying systems have been used to overcome any undesirable effects that arise from sun-drying with grape cultivars that require fewer pesticides to minimize the risk of residues. Both seeded and seedless cultivars were preferred for drying in the past; however, seedless grape cultivars have been increasingly preferred for drying purposes in addition to their use as table grapes. For the first time, an alternative processing method (using an energy-saving heat pump dryer) and important quality characteristics (total phenolics, antioxidant activity, brix, colour analyses and sensory evaluation) of disease resistant/tolerant grape cultivars of different species that can be grown in humid regions were investigated in this study. First, the fresh fruits of nine different grape (Vitis spp.) cultivars grown in a humid ecology were analysed, and then so too were the important phytochemical and quality characteristics of raisins dried with an energy-saving heat pump dryer. The water activity of the raisins ranged from 0.71 (Özer Beyazı) to 0.42 (Kay Gray). The total phenolic contents of Muscat Bleu (65.96), Philipp (64.88) and Campbell Early (64.53 g GAE/100 g db) berries were the highest (p < 0.05). The fresh berries of the Kishmish Vatkana cultivar had the lowest antioxidant activity, as determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay (525.81 mmol TE/100 g) (p < 0.05). The total phenolic contents of raisins ranged from 12.76 to 13.58 g GAE/100 g fw. The highest value on a dry weight basis was 19.30 g GAE/100 g for the raisins of the Özer Beyazı cultivar (p < 0.05). The highest antioxidant activity value on a dry weight basis was found for the raisins of Özer Beyazı (991.01 mmol TE/100 g) using the DPPH assay. The raisins of the Philipp cultivar had an antioxidant activity of 7893.51 mmol TE/100 g db, as determined by the ferric reducing antioxidant potential (FRAP) assay, which was significantly higher than those of other cultivars, with the exception of Muscat Bleu (p < 0.05). The range for antioxidant activity values provided by the cupric reducing antioxidant capacity (CUPRAC) assay was high, and the highest value was found for the raisins of the Philipp cultivar (4505.21 mg Trolox/100 g fw) (p < 0.05). The results indicated that the raisins of the seedless Rhea and Kishmish Vatkana cultivars can be appreciated more than those of the other cultivars, both in terms of their bioactive content and sensory scores, and the raisins of these cultivars, which can be grown in humid regions, hold a great deal of potential for grape growers.

The main purpose of this study is to determine the contents of 3 major phenolic compounds (gallic acid, catechin, and epicatechin) in 22 different grape cultivars/hybrids obtained from 2 different breeding programs. Additionally, changes in these phenolic components in the grape leaves of some resistant/tolerant species were determined in relation to powdery and downy mildew diseases in viticulture. The skin, pulp, and seeds of grape berries were analysed over two years, while changes in the phenolic contents of grape leaves were determined before and after these diseases for two years. The major phenolic contents of new hybrids/cultivars were compared with those of popular cultivars in different parts of the grapes, and significant differences in phenolic contents were found among hybrids/cultivars and different grape parts. Variations in the contents of phenolics in grape seeds, skins, and pulp were high, but seeds contained higher levels of these phenolics than pulp and skin. Analyses of the relationship between two viticultural diseases and phenolic changes in resistant/tolerant cultivars in relation with the susceptible “Italia” cultivar revealed that an increase in the content of the phenolic compounds was found after powdery mildew disease. Hybrids/cultivars with high phenolic contents are recommended to develop new superior cultivars, which are resistant to grape fungal diseases, in breeding programs.

The presence of dormant embryos in seeds and nonuniformity in seedling growth are the main limiting factors for kiwifruit propagation. Studies on the germination of hybrid genotypes are limited, especially at different ploidy levels. Low germination percentages and nonuniformity in seedling growth are two of the limiting factors of kiwifruit breeding, especially new and imported germplasm. The effect of cold moist stratification and growing substances on seed germination and seedling growth, respectively, on different kiwifruit seed populations were evaluated in this study. The effect of cold moist stratification (3, 4 and 5 weeks at 4 °C) and growing substrate composition (peat, perlite and coco peat) on seed germination and seedling growth of different Actinidia genotypes were assessed. In general, increasing stratification period duration often increased germination speed and uniformity. It was also found that increasing the ratio of peat moss improved the vegetative growth parameters of all kiwifruit seedlings. Stratification treatment, light and temperature fluctuation and consequently suitable substrate can accelerate and increase the production of seedlings and reduce seedling losses. It was also found that peat–perlite (1:1) medium was the best medium for kiwifruit seedling growth.

Downy (Plasmopara viticola) and powdery mildew (Erysipha necator) is known as one of the most mischievous diseases for viticulture in Turkey as well as in the world. Therefore breeding studies play an important role for development of new cultivars resistant against fungal diseases. The aim of this research was to develop new F1 population and evaluate the resistance of hybrids to powdery and downy mildew via marker assisted selection (MAS). Resistant ‘Regent’ and susceptible ‘Boğazkere’ varieties were used to obtain hybrid population. A total of 6 markers belonging to 3 genomic regions were used for DNA based selection. Four SSR (UDV15, VMCNG2f12, VMC7F2 and UDV305) and two SCAR (ScORNA7-760 and ScORN3-R) markers which were developed to the resistance loci of Rpv3 and Ren3 were used for DNA based selection. The results were evaluated together with powdery mildew inoculation observations. When inoculation observations and MAS were evaluated, genotypes resistant, tolerant and susceptible to powdery and downy mildew were identified. Especially 16 genotypes identified as resistant to powdery mildew, can be used in future breeding programs.