2022 Volume 91 Issue 1 Pages 9-15
Field experiments were conducted in a farmer’s field in Akita Prefecture, from 2017 to 2019 to examine whether a practical amount of seeds can be treated to obtain pre-germinated seeds with elongated roots but not elongated coleoptiles, referred to as root-elongated seeds hereafter, and to examine their seedling establishment and early growth in comparison with pre-germinated seeds and iron-coated seeds. Seed samples, 15 to 48 kilograms in weight, of the cultivars ‘Chihominori’ and ‘Moeminori’ were treated in a steam nursery chamber at 30°C to obtain root-elongated seeds. Seeds with appropriate root lengths were obtained after 36~41 hours of treatment in‘Chihominori’ and after 30~45 hours of treatment in ‘Moeminori’. The root-elongated seeds and pre-germinated seeds were sown with a puddling seeder in flooded paddy fields. Iron-coated seeds were broadcast with a knapsack duster as the conventional practice. The seedlings grown from root-elongated seeds were longer and had higher leaf numbers at the seedling emergence stage than those from the pre-germinated seeds and seedling establishment and growth at the seedling establishment stage were better, although the differences were not statistically significant. The seedlings grown from the root-elongated seeds were longer and heavier and had higher leaf numbers than the iron-coated seeds at the seedling establishment stage. The lodging and yield of the plants grown from the root-elongated seeds were the same as those grown from the pre-germinated and iron-coated seeds. In conclusion, a practical amount of root-elongated seeds could be obtained using a nursery chamber, and seedling establishment and growth in the farmer’s field were improved.
