Context and aims: Freshly harvested seeds of temperate annual pasture legume species have physiological dormancy (PD), which delays the growth of the next generation and is thus an impediment to speed breeding. The aim of this study was to develop a method or methods of PD breaking that can achieve high germination (≥90%) within 5 days of picking freshly harvested seed.

Methods: In a series of experiments, PD breaking methods by themselves and in combination were tested on burr medic (Medicago polymorpha). The most promising methods were then tested on other annual medic species (Medicago spp.), subterranean clover (Trifolium subterraneum), and alternative species from six genera.

Key results: The successful PD breaking method involved drying pods overnight at 45°C, extracting and scarifying seed, placing seed on filter paper in a Petri dish along with non-dormant seed, imbibing seed with 4 μM benzylaminopurine, sealing the Petri dish, and incubating in the dark at 15°C. Highly dormant genotypes required the additional treatment of removing the testa.

Conclusions: We have developed an effective way of breaking seed PD in the 11 pasture legumes species from the seven genera tested. The rapid breaking of seed PD will assist speed breeding of annual pasture legumes, making it less laborious and time-bound than currently used methods.

Implications: The PD breaking methods are expected to assist basic science studies of annual pasture legume species and may be applicable to other species and genera.

背景和目标：温带一年生牧草豆科植物新收获的种子具有生理休眠（PD），这会延迟下一代的生长，从而阻碍加速繁殖。本研究的目的是开发一种或多种 PD 破碎方法，可在采摘新鲜收获的种子后 5 天内实现高发芽率 (≥90%)。

方法：通过一系列实验，对紫花苜蓿（Medicago polymorpha）进行单独和组合的局部放电破坏方法的测试。然后，最有前途的方法在其他一年生药用植物（Medicago spp.）、地下三叶草（Trifolium subterraneum）和六个属的替代物种上进行了测试。

主要结果：成功的 PD 破坏方法包括在 45°C 下干燥豆荚过夜，提取并划伤种子，将种子与非休眠种子一起放在培养皿中的滤纸上，用 4 μM 苄氨基嘌呤吸收种子，密封培养皿，并在 15°C 下避光孵育。高度休眠的基因型需要额外的去除种皮的处理。

结论：我们已经开发出一种有效的方法来破坏所测试的 7 个属的 11 种牧草豆科植物的种子 PD。种子PD的快速破碎将有助于加速一年生牧草豆类的育种，使其比目前使用的方法更省力、更省时。

意义： PD 破坏方法预计将有助于一年生牧草豆科植物的基础科学研究，并可能适用于其他物种和属。