Fruit cracking poses a significant challenge to ‘Sinhwa’ pear cultivation and has potential economic repercussions for growers due to its adverse effects on yield and fruit quality. This study delves into the phenomenon of fruit cracking in ‘Sinhwa’ pears by conducting a comprehensive analysis of its causes and exploring the efficacy of foliar fertilization as a mitigation strategy. To reveal the conditions contributing to fruit cracking in ‘Sinhwa’ pears, moisture change regimes were systematically applied to 5-year-old ‘Sinhwa' trees from 2018 to 2020 during post-flowering and harvest periods. Alternating wet and dry conditions resulted in the highest fruit cracking rates, thus highlighting the importance of consistent soil moisture levels for mitigating cracking. Furthermore, the timing of fruit cracking and its histological characteristics in ‘Sinhwa’ pears were examined to understand the underlying causes. Microcracks appeared approximately 60 days after full bloom and preceded visible cracking, although notable changes in epidermis thickness and stone cell layer distribution were observed. Analysis of the nutrient content revealed differences in calcium and potassium levels between intact and cracked fruits, thus providing insights into potential nutritional influences on fruit quality. Potential mitigation strategies included foliar application of 0.3 % calcium chloride and 0.5 % potassium nitrate, and they demonstrated promising results in reducing fruit cracking rates compared to the control. Fruit characteristics, including mass and hardness, varied among the treatment groups, with treated trees showing notable increases in calcium content, which were correlated with decreases in fruit cracking incidence. To understand the molecular mechanisms underlying the effectiveness of foliar fertilization, gene expression levels associated with fruit cracking were analyzed by real-time PCR. Higher expression of heat-related expansion genes (1 and 2) was observed in the treated fruits, particularly those in the calcium chloride and potassium nitrate treatments, suggesting the role of these elements in mitigating fruit cracking. This study provides valuable insights into the causes of fruit cracking in ‘Sinhwa’ pears and offers practical mitigation strategies, such as foliar fertilization. Moreover, the findings underscore the importance of maintaining consistent soil moisture levels and optimizing nutrient management practices to enhance fruit quality and minimize economic losses in ‘Sinwha’ pear cultivation.

中文翻译：

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新华梨裂果机制及叶面肥对果实品质的影响

裂果对“神话”梨的种植构成了重大挑战，并且由于其对产量和果实质量的不利影响而对种植者产生潜在的经济影响。本研究通过全面分析“新华”梨裂果现象的原因并探索叶面施肥作为缓解策略的功效，深入研究了“新华”梨的裂果现象。为了揭示导致“Sinhwa”梨裂果的条件，我们在 2018 年至 2020 年开花后和收获期对 5 年生“Sinhwa”梨树进行了系统的水分变化。干湿交替的条件导致果实开裂率最高，因此凸显了保持土壤湿度一致对于减轻开裂的重要性。此外，还检查了“Sinhwa”梨的裂果时间及其组织学特征，以了解根本原因。尽管观察到表皮厚度和石细胞层分布发生显着变化，但微裂纹在盛花后约 60 天出现，并且先于可见的裂纹。对营养成分的分析揭示了完整水果和裂开水果之间钙和钾含量的差异，从而深入了解营养对水果质量的潜在影响。潜在的缓解策略包括叶面喷施 0.3% 氯化钙和 0.5% 硝酸钾，与对照相比，它们在降低裂果率方面表现出良好的效果。果实特性（包括质量和硬度）在处理组之间存在差异，经过处理的树木钙含量显着增加，这与裂果发生率的降低相关。为了了解叶面施肥有效性的分子机制，通过实时 PCR 分析了与裂果相关的基因表达水平。在处理的果实中观察到与热相关的膨胀基因（1和2）的较高表达，特别是在氯化钙和硝酸钾处理中的果实，表明这些元素在减轻果实裂裂中的作用。这项研究为“新华”梨裂果的原因提供了宝贵的见解，并提供了实用的缓解策略，例如叶面施肥。此外，研究结果强调了保持土壤湿度稳定和优化养分管理实践的重要性，以提高“Sinwha”梨种植的水果质量并最大限度地减少经济损失。