臺灣本地桃樹的需冷量評估與模式開發

Estimation of the Chilling Requirement and Development of a Low-chill Model for Local Peach Trees in Taiwan

臺灣農業試驗所緯度24°1'59' ,海拔約85公尺，從1991～1998年間冬天每年平均低於12 9°C的低溫累積量玲370小時。八年來本地桃樹與新選雜交後代需冷量的評估是藉著比較4個「關鍵栽培種」（亦即'Flordared'、、Prem;er'、'TropicSweet'和·TropicSnow'等）與待評估栽培種間的花期早晚，並收集八年間感應低溫起始日至休眠完成期與盛花期之間每小時的平均溫度記錄，以便開發適合低需冷地區應用的臺灣新需冷模式。各關鍵栽培種的需冷量計算，即從感應低溫起始日至休眠完成或至盛花期所累積的低溫，經囪外採用的三種不同低溫模式（即低於12.9°C的小時數、低需冷油桃模式與猶他低溫單位模式等三種）的測試結果，這些模式所累積的低溫皆偏低很多。經本所以「試誤法」從33 0萬餘組的測試組合中，所開發出來的臺灣需冷模式，用來測試4個關鍵栽培種的需冷量，結果顯示新模式較國外高需冷地區所開發的三個需冷模式表現更為精確。採用臺灣需冷模式對本地桃樹需冷量的評估為：砂桃210低溫單位（chill unit, CU），福州大桃200CU，雞慶桃190CU，苦桃180CU，鶯歌桃170 CU , 7612（'Flordared' x Flordaprince'）150 CU , 7669（'Premier x 'Flordabelle'）180 CU。

Taiwan Agriculture Research Institute. latitude of 24 ° I'59', and altitude of 85m, has an average annual chilling hours of 370 hours below 12.9°(. The chilling requirements for local peach cultivars and new selections had been determined by the comparison of blooming dates with '4 key cultivars' ('Flordared'. 'Premier','TropicSweet', and'TropicSnow') for 8 years. The peach phenological data, including the hourly mean temperature records between the initial dates of chilling to rest completion dates and full blooming -dates from 1991 to 1997, were collected for developing a new chill model for low chill regions (Taiwan chilling model). Chilling requirements for key cultivars were calculated from the initial dates of chilling to rest completion by 3 different models which were named the number of hours below 12.9°(, low-chilling nectarine model, and Utah chill-unit model. These models underestimated the accumulated chilling. The Taiwan chilling model developed by 'try and error method' from more than 3.3 milion combinations when tested with the '4 key cultivars' performed more accurately than the other three chilling models developed in higher chill zones. Using the Taiwan chilling model the chilling requirement of peach genotypes were estimated as 210 CU for'Swa-taur'. 200 CU for 'Fu-jou-dah-taur', 190 CU for非ching-taur', 180 CLJ for 'Kuu-taur', 170 CU for'ln-ge-taur'. 150 CU for 7612 ('Flordared' x'Flordaprince') and 180 CU for 7669 ('Premier'x'Flordabelle').