Apple fruitlet drop prediction using spectral Vis/NIR and growth diameter times-series

Apple fruitlet drop prediction using spectral Vis/NIR and growth diameter times-series | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Apple fruitlet drop prediction using spectral Vis/NIR and growth diameter times-series Konni Biegert, Stefano Modugno, Silas Föll, Magdalena Peterlin, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5217952/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In apple production different thinning strategies are applied to produce optimal yields of marketable fruit and to reduce the risk of alternate bearing. However, the effectiveness of a chemical thinning treatment is highly variable being influ- enced by the tree’s physiological state and environmental conditions both before and after application. Optical sensing with a visible/near-infrared spectropho- tometer is tested as a prediction tool to decide if a further thinning treatment is required and precisely thin trees in the orchards. In 2023, in Southwest Ger- many and in Northern Italy, the apple cultivars ‘Gala’ and ‘Braeburn’ were thinned between the 8-15 mm fruit diameter growth stage. King and second lateral fruitlets, which were the target of the thinning, were measured with dig- ital calipers and scanned before and up to 13 days after thinning treatments. Thinning treatments effectively reduced fruit set by one half. Receiver operating characteristic curves were tested separately on spectral indices and fruit diame- ter growth. Spectral monitoring recorded similar information as measuring fruit diameter growth. The obtained area under the curve was > 75% on 5-8 days after treatment for both cultivars. Persisting fruitlets showed higher light absorption in the chlorophyll and water related wavelength regions and higher light reflectance from the near-infrared region (699 to 939 nm). Horticulture sensing abscission growth processes thinning efficacy precision horticulture Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5217952","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":408396343,"identity":"5b9fbd70-7c74-494d-b43d-53ab10ed28d4","order_by":0,"name":"Konni 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However, the effectiveness of a chemical thinning treatment is highly variable being influ- enced by the tree’s physiological state and environmental conditions both before and after application. Optical sensing with a visible/near-infrared spectropho- tometer is tested as a prediction tool to decide if a further thinning treatment is required and precisely thin trees in the orchards. In 2023, in Southwest Ger- many and in Northern Italy, the apple cultivars ‘Gala’ and ‘Braeburn’ were thinned between the 8-15 mm fruit diameter growth stage. King and second lateral fruitlets, which were the target of the thinning, were measured with dig- ital calipers and scanned before and up to 13 days after thinning treatments. Thinning treatments effectively reduced fruit set by one half. Receiver operating characteristic curves were tested separately on spectral indices and fruit diame- ter growth. Spectral monitoring recorded similar information as measuring fruit diameter growth. The obtained area under the curve was \u003cem\u003e\u0026gt;\u003c/em\u003e75% on 5-8 days after treatment for both cultivars. 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