Representing cumulative germination. 1. A critical analysis of single-value germination indices

Abstract

Several single-value germination indices, including Kotowski's coefficient of velocity, Maguire's speed of germination, Czabator's germination value, Diavanshir and Pourbiek's germination value, Timson's cumulative germination, Lehle and Putnam's Richards function index, Smith and Millett's sprouting index, and Tucker and Wright's regression index, were evaluated to test their ability to distinguish superior from inferior germination. All except Timson's cumulative germination method were essentially no better for ranking germination responses than data on total germination; Kotowski's coefficient of velocity, Smith and Millet's sprouting index, and Lehle and Putnam's Richards function index were markedly inferior. Because of the ambiguity inherent in any index that combines, into a single value, data about the onset, rate and extent of germination, none of the indices could be recommended as a way of summarizing germination.