The influence of the preharvest application of chitosan on physicochemical properties and changes in gene expression of ‘Garmrok’ kiwifruit during postharvest cold storage (0 °C; RH 90–95%; 90 days) was investigated. Preharvest treatment of chitosan increased the fruit weight but had no significant effect on fruit size. The chitosan treatment suppressed the ethylene production and respiration rate of kiwifruit during the cold storage. The reduction of ethylene production of chitosan-treated kiwifruit was accompanied with the suppressed expression of ethylene biosynthesis genes. Moreover, preharvest application of chitosan diminished weight loss and delayed the changes in physicochemical properties that include firmness, soluble solids content, titratable acidity, total sugars, total acids, total phenols, and total lignin. As a result, the preharvest application of chitosan delayed the maturation and ripening of fruit. Expression of genes related to cell wall modification was down-regulated during the early maturation (ripening) period, while those related to gene expression for lignin metabolism were up-regulated at the later stages of ripening. These results demonstrate that the preharvest application of chitosan maintained the fruit quality and extends the postharvest life of ‘Garmrok’ kiwifruit, possibly through the modulation of genes related to ethylene biosynthesis, cell wall modification, and lignin metabolism.

Climate change, a pressing global concern, poses significant challenges to agricultural systems worldwide. Among the myriad impacts of climate change, the cultivation of kiwifruit trees (Actinidia spp.) faces multifaceted challenges. In this review, we delve into the intricate effects of climate change on kiwifruit production, which span phenological shifts, distributional changes, physiological responses, and ecological interactions. Understanding these complexities is crucial for devising effective adaptation and mitigation strategies to safeguard kiwifruit production amidst climate variability. This review scrutinizes the influence of rising global temperatures, altered precipitation patterns, and a heightened frequency of extreme weather events on the regions where kiwifruits are cultivated. Additionally, it delves into the ramifications of changing climatic conditions on kiwifruit tree physiology, phenology, and susceptibility to pests and diseases. The economic and social repercussions of climate change on kiwifruit production, including yield losses, livelihood impacts, and market dynamics, are thoroughly examined. In response to these challenges, this review proposes tailored adaptation and mitigation strategies for kiwifruit cultivation. This includes breeding climate-resilient kiwifruit cultivars of the Actinidia species that could withstand drought and high temperatures. Additional measures would involve implementing sustainable farming practices like irrigation, mulching, rain shelters, and shade management, as well as conserving soil and water resources. Through an examination of the literature, this review showcases the existing innovative approaches for climate change adaptation in kiwifruit farming. It concludes with recommendations for future research directions aimed at promoting the sustainability and resilience of fruit production, particularly in the context of kiwifruit cultivation, amid a changing climate.

This study investigated pollen application methods for artificial pollination in tetraploid kiwifruit cultivars ‘Halla Gold’ and ‘Sweet Gold’ grown in a nonheated plastic-film house in Jeju, Korea. Pollen of the hexaploid cultivar ‘Bohwa’ (A. chinensis var. deliciosa) bred in Korea was used for artificial pollination. We examined the effect of repeated pollination, pretreatment of stigma with wetting materials, application of dry pollen or pollen in suspension on fruit quality, and seed formation. With repeated pollination, pollen tubes in the pistil reached and penetrated the ovule three days after artificial pollination, although the pattern varied depending on the number of dry pollen applications. In both cultivars, the number of pollen tubes was clearly higher following repeated pollination than following single pollination, and fruit weight, dry matter (DM), number of seeds, and 100-seed weight were also higher. When pistillate flowers were pollinated with dry pollen immediately after water sprinkle, both cultivars showed the lowest fruit weight, DM, firmness, number of seeds, and 100-seed weight, whereas there were no significant differences in fruit quality or seed formation for dry pollen application 1 h after water sprinkle, or immediately or 1 h after suspension medium sprinkle. For pollination using a pollen suspension, the fruit weight was lower in both cultivars. There were no significant differences in fruit quality and seed formation following application of dry pollen or a pollen suspension, except for fruit weight in ‘Sweet Gold’. It could be seen from the results of this study that raindrops or dewdrops on the stigma might reduce the efficiency of artificial pollination using dry pollen. Still, the application of repeated pollination enhanced the efficiency of artificial pollination.

Tea, derived from the evergreen shrub Camellia sinensis (L.) O. Kuntze, is one of the most widely consumed beverages globally, playing a significant socioeconomic role in many tropical and subtropical regions. However, tea cultivation is increasingly threatened by climate change, which is affecting growth, yield, and quality. This review explores the current status and prospects of tea plants' responses to climate change. The present study outlines the direct and indirect impacts of climate change including rising temperatures, altered precipitation patterns, and a rise in pest and disease outbreaks, on tea growing regions and tea production. The current study discusses the physiological and biochemical responses of tea plants to climate stressors including temperature stress, water stress and elevated CO 2 levels. It also explores the key adaptive strategies employed by tea farmers, including agricultural practices, breeding and genetic improvement, and pest and disease management. Additionally, the review highlights breeding efforts to develop climate-resilient tea cultivars and the role of traditional and biotechnological approaches in tea plant breeding and genetic improvement. Innovations to mitigate climate impacts on tea plantations such as assessing tea's long-term response to climate change and enhancing tolerance to combined stress conditions are briefly outlined. While progress has been made, significant research gaps remain in understanding the long-term responses of tea plants to climate stressors. Future efforts should focus on continued research, innovation, and collaboration to ensure the sustainability of tea production in a changing climate.

Actinidia arguta is a Korean native kiwifruit with valuable traits for kiwifruit breeding, such as cold hardiness, disease tolerance, and high nutritional value. Early sex discrimination is a priority in kiwifruit breeding programs because Actinidia species are dioecious vines. A cleaved amplified polymorphic sequence (CAPS) marker discriminating sex was developed using genotyping-bysequencing (GBS)-derived single nucleotide polymorphisms (SNPs). Previously obtained GBS reads were realigned to the kiwifruit reference genome organized at the pseudo-chromosomal level. These GBS-SNPs could divide A. arguta accessions according to sex. Candidate CAPS markers were designed using these SNPs located on sex chromosomes. Among them, only the CAPS marker designed using the SNP located at 10,236,410 bp on sex chromosome was able to discriminate the sex of A. arguta accessions. This might be because the SNP located at 10,236,410 bp had higher read depth than other candidate SNPs. This CAPS marker, named CBk25ca01, produced DNA fragments of 300 and 147/153 bp in female and male A. arguta accessions, respectively. The CBk25ca01 marker will be useful to improve kiwifruit breeding programs by reducing the time needed to discriminate sex.