Treatment of Rice Seeds for Early Growth, 2019

 

Dennis O'Connor, assistant professor of mechanical and mechatronic engineering, CSU Chico

This new project aims to find ways to treat rice seeds that improve early plant growth. Sowing good quality seeds can lead to lower seed rate requirements, better emergence, more uniformity, less replanting, and vigorous early growth to increase resistance to insects and diseases, and to decrease weeds. Thus, this has the potential to increase yields. First year objectives were to expand research on accelerated early plant growth of rice in both field and greenhouse trials.

At Chico State, researchers tested a novel biophysical treatment of S-102 seeds. This involved temporarily exposing the seeds to vibrating water upon initial soaking. Seven experiments were conducted to quantify accelerated germination rates. A consistent, accelerated germination rate was observed in the biophysical treatments, reaching nearly 10% in treated seeds starting at day two and leveling off at day five.

At Lundberg Family Farms, a different set of experiments focused on early plant growth vigor in both greenhouse and field trials. Research staff monitored treated and untreated plants of M-206, Akitakomachi, and S-102. These three varieties were tested to understand broader impacts of treatments and to see if common varieties stand to benefit.

Rice seedlings not only got a head-start with quicker germinations rates, but they also exhibited improved early growth or seedling vigor. Thus, root length and shoots were measured in both greenhouse and field trials.

In field measurements, the average root and shoot lengths of M-206 were mostly larger in the control, yet the exact opposite was found in the greenhouse. Results for Akitakomachi were less consistent, with the greater average length measurements switching back and forth between controls and treated for both the greenhouse and field trials. S-102 results for the control and treated seeds were also less consistent.

Researchers believe with a high degree of confidence that the germination rate increased as a result of the biophysical treatment. Post germination observations have shown substantially improved seedling vigor for treated seeds over the control.

Multiple greenhouse trials and the field trial to observe any continued benefit after germination failed initially to show consistent results. However, subsequent trials showed better results, which suggests a growth advantage in treated seeds.