Understanding the relative longevity of different seed lots, perhaps of different species or genotypes, but also following production under different environments or using different cultivation methods, or following different post-harvest treatments, is relevant to anyone concerned with the retention of seed lot viability and vigour during storage. However, different scientists over the years have used different conditions to assess seed lot longevity, as well as different variables as the measure of ‘longevity.’ Here, we give some of the backgrounds to how two standard protocols, with an open and closed system respectively, were derived, and explain why we consider p50, defined as the time during storage when seed lot viability, as measured through a germination test, has declined to 50%, is a suitable longevity trait parameter.

了解不同种子批次（可能是不同物种或基因型）的相对寿命，以及在不同环境下生产或使用不同的栽培方法，或采用不同的收获后处理后，对于任何关心种子批次活力保留和储存期间的活力。然而，多年来，不同的科学家使用不同的条件来评估种子批次的寿命，以及不同的变量作为“寿命”的衡量标准。在这里，我们给出了两个标准协议（分别具有开放系统和封闭系统）的一些背景，并解释了为什么我们考虑第50页，定义为通过发芽试验测量的种子批次活力下降到 50% 的储存时间，是一个合适的长寿性状参数。