Chilling of Endodormant Peach Propagules: V. Comparisons between Seeds, Seedlings, and Cuttings

Abstract

We determined whether the chilling process (endodormancy release) was similar in peach [Prunus persica (L.) Batch cv. Johnson Elberta] seeds, seedlings (near normal to physiologically dwarfed), and mature plants (cuttings) by comparing correlation coefficients of various growth measurements following similar chilling treatments. Seed germination (10 days after forcing at 20C) and seedling emergence (15 days after forcing in the greenhouse) correlated highly with leaf and shoot growth (56 days of growth) of seedlings and terminal shoot growth of cuttings (13 days after forcing). The correlations were higher for germination than for emergence. Initial (first season) seedling growth correlated poorly with germination, emergence, budbreak, and growth of seedlings (second season) and shoot growth of cuttings. Budbreak and growth of seedlings correlated highly with shoot growth of cuttings. The abnormal leaf problem, which can cause apex abortion (common with initial seedling growth), confounded correlations with initial seedling growth. Yet, the abnormal leaf problem did not hinder correlations with the second seasons growth. Good relationships between the chilling mechanisms that promoted germination, emergence, budbreak, and growth of seedlings and shoot growth of cuttings existed, but were dependent on what was measured and when the measurement was taken. Germination (forced at 20C) was the most accurate indicator of the seed chilling status for comparisons with the responses of the other propagules.