Rootstock and Seasonal Influences on Carbohydrate Levels and Cold Hardiness of ‘Redhaven’ Peach1

Abstract

Abstract Flower buds and apical shoots of ‘Redhaven’ peach ( Prunus persica (L.) Batsch) were shown to be slightly more cold hardy in the autumn and winter when propagated on seedlings of Siberian C than on those of Harrow Blood. Apical shoots consistently had higher levels of total carbohydrates, reducing sugars, and other carbohydrate fractions on Siberian C than on Harrow Blood seedlings from winter to spring. The cold hardiness of flower buds was closely correlated with the hardiness of apical shoots. In addition, both flower bud and shoot hardiness were closely correlated with total sugars, sucrose, and reducing sugars in the shoots from autumn to spring. However, hardiness of flower buds and apical shoots was not correlated with total carbohydrates or starch. The TI 50 , a new method of expressing the hardiness of apical shoots was an objective index of cold hardiness and somewhat analogous to the T 50 method for expressing hardiness of flower buds.