Effect of planting depth and pre-planting seed treatments on seedling emergence and early growth of different hill rice cultivars (Oryza glaberrima Steud.)

Rice (Oryza spp.), is an important global staple and vital component in food and nutrition security in Small Island Developing States (SIDS) such as Trinidad and Tobago, where Oryza glaberrima (Moruga hill rice) is traditionally cultivated. This study aimed to evaluate the impact of planting depth and pre-planting seed treatments on seedling emergence and growth on Moruga hill rice. A factorial experiment was conducted with three cultivars (‘Bongo toffee’, ‘Bongo farina’ and ‘Beard’), three planting depths (2.5 mm, 30 mm and 60 mm) and four pre-planting seed treatments [soaking seeds in 0.0014 M gibberellic acid (GA1); soaking seeds in 0.0029 M gibberellic acid (GA2), soaking in distilled water (DW) and dry seeding (DS)]. Significant three-way interactions among cultivar, planting depth and pre-planting seed treatments were obtained for days to first emergence, time to 50% emergence, root length, plant height, first leaf length, root and shoot fresh and dry weights. All cultivars planted at 2.5 mm and treated with GA1 or GA2, as well as cultivars ‘Bongo Toffee’ and ‘Bongo Farina’ under DW, emerged faster than all other treatments Application of gibberellic acid was a significant factor in growth and total emergence rate of rice seedlings. Planting depth had an inverse effect on plant height, with shallower planting resulting in taller plants. This study highlights the role of optimum planting depth and effective pre-planting seed treatments in improving seedling establishment and growth among Moruga hill rice cultivars (Oryza glaberrima) for efficient cultivation and production.