ABSTRACT

The annual regeneration from seeds of subterranean clover plants after initial sowing depends on the hardseededness (HS_max, %), its breakdown rate (HS_break, %/ °C) and the germinability of the seeds over time. Hardseededness is a physical mechanism of dormancy that prevents germination of seeds and is ecologically important for the persistence of subterranean clover in a range of environments. The effects of genotype (G) and sowing time (environment, E) on hardseedednes and germination were investigated for ‘Antas’, ‘Denmark’, ‘Leura’, ‘Monti’, ‘Narrikup’ and ‘Woogenellup’ harvested from six different sowing dates (June 2015–March 2016) in a field experiment in Canterbury, New Zealand. ‘Antas’ had a lower HS_max (53%) than ‘Monti’ (86%). HS_break was affected by the G x E interaction with a doubling of HS_break from 0.011%/°C for the June sowing date to ∼0.02%/°Cd for the February sowing date for ‘Denmark’, ‘Leura’, ‘Monti’ and ‘Narrikup’. There was less sensitivity of ‘Antas’ and ‘Wogenellup’ to sowing time. There was an increase in the percentage of abnormal seedlings as the sowing date advanced from winter to late-summer. The developed parameters enabled estimation of seedling emergence and indicate cultivars which have a competitive advantage of an early seedling regeneration in temperate regions.

摘要

地下三叶草种子在初次播种后的年度再生取决于种子的硬化率 (HS _max , %)、分解率 (HS _break , %/ °C) 和种子随时间的发芽能力。Hardseedness 是一种休眠的物理机制，可防止种子发芽，并且对于地下三叶草在一系列环境中的持久性具有重要的生态学意义。研究了从六种不同播种中收获的'Antas'、'Denmark'、'Leura'、'Monti'、'Narrikup'和'Woogenellup'的基因型（G）和播种时间（环境，E ）对硬籽和发芽的影响日期（2015 年 6 月至 2016 年 3 月）在新西兰坎特伯雷的实地实验中。'Antas' 的 HS_{最大值较低}（53%）比“蒙蒂”（86%）。HS_断裂受G x E相互作用的影响，HS_断裂从 6 月播种日期的 0.011%/°C 到 2 月播种日期的 ∼0.02%/°Cd 的 'Denmark'、'Leura'、'Monti '和'纳里库普'。'Antas' 和'Wogenellup' 对播种时间的敏感性较低。随着播期从冬季提前到夏末，异常幼苗的百分比增加。开发的参数可以估计出苗率，并表明在温带地区具有早期幼苗再生竞争优势的品种。