Stimulation of seed germination and productivity of legume grasses

Abstract

To identify technological approaches aimed at improving the quality of legume grass seeds, studies were conducted on the effects of a super-high frequency (SHF) electromagnetic field on the sowing qualities of red clover (Trifolium pratense) and Hungarian sainfoin (Onobrychis arenaria) seeds. The experiments employed a continuous-wave irradiation setup. Air-dry seed material was treated. The exposure time was as following: 10, 20, 30, 40, 50, 60, and 70 s. The research targets were the varieties adapted to the foothill zone of the North Caucasus: red clover ‘Daryal’ and Hungarian sainfoin ‘Zernogradskiy 2’. The effectiveness of super-high frequency treatment was assessed using laboratory indices of germinating energy and laboratory germination as well as morphometric traits of seedlings. In addition, under collection nursery conditions, the accessions of both crops were evaluated and comparatively studied for a set of quantitative and qualitative characters to relate field performance to laboratory results. The most pronounced stimulatory effect was observed at exposures of 30…50 s at a power of 800 W: germinating energy exceeded the control by 12.3…13.8%, and laboratory germination increased by 11.1…13.4%. Improvements in seedling indices were also recorded: root length increased by 5.3…6.2 cm and root weight by 0.31…0.34 g. A practically important outcome was earlier seedling emergence (by 2…3 days). With longer exposure (60…70 s), an opposite trend was observed - both germinating energy and germination decreased thus indicating that exceeding the optimal exposure time was undesirable. The analysis of field experimental data showed that pre-sowing SHF activation of seeds was associated with increased productivity of clover and sainfoin. This effect was associated with higher emergence (by 11…17%), increased survival (by 2.8…3.1%), and improved plant stand persistence (by 1.9…2.8%). In addition, the development rates accelerated by 10…12%, and photosynthetic activity increased by 11.1…21.4%.