Selection of Early Lines without Frost Damage Based on Parameters of Accumulated Temperature for Flushing and Opening Speed of New Leaves in Tea

Abstract

Given the demand by farmers for early budding cultivars in tea, this study was carried out to select moderately early lines without frost damage, as well as lines showing rapid growth after flushing among 1,300 tea (Camellia sinensis) accessions preserved at the Makurazaki Station of the National Institute of Vegetable and Tea Science, Japan. A model for flushing and leaf opening [y = (ax+b), y: number of open leaves, x: effective accumulated temperature calculated by integrating values of temperatures being 10°C below the daily minimum air temperature since the date of autumn skiffing and a, b: parameters] was developed before the selection. For the selection, the estimated parameters were used as indicators of the flushing temperature and opening speed of tea leaves. As a result, 120 moderately early lines, 79 rapidly growing lines and 12 lines (parameter a>0.5, x 0 = 145-150°C) with both characteristics were selected. Furthermore, Taiwan-yamacha which showed extremely late flushing characteristics, accounted for 44 of the 68 late flushing lines and is expected to be used as breeding material to extend the harvesting period for the first crop.Discipline: Genetic resources / Plant breeding / Tea industry Additional key words: Camellia sinensis, sensitivity to temperature JARQ 37 (3), 183 -188 (2003) http://www.jircas.affrc