Effect of Seed Maturity and Invigoration on Seed Viability and Vigor, Plant Growth, and Yield of Bambara Groundnut (Vigna subterranea (L.) Verdcourt)

Abstract

Bambara groundnut can be cultivated in marginal land, however, its productivity is still low. In order to increase productivity, high quality seeds must beused. Two consecutive experiments were conducted in the laboratory and field at Bogor Agricultural University from April to October 2010. Seeds of three maturity stages were harvested from a farmer’s field in Sukabumi, April 2010. The seeds were dried down to 11.6% moisture content before being used. The objectives of the experiments were to evaluate the effects of seed invigoration applied to Bambara groundnut seeds of three maturity stages, on seed viability and vigor, plant growth, and yield. The laboratory experiment was arranged in a completely randomized design (CRD) while the field experiment was arranged in a randomized block (RBD) design. In both experiments, two factors were tested; seed maturity and invigoration. There were three stages of seed maturity i.e., seeds harvested at 119, 122, and 125 days after planting (dap). Seed invigoration consisted of untreated, Rhizobium sp., matriconditioning, matriconditioning plus Rhizobium sp. Matriconditioning was conducted using ratio of seeds to carrier (burned rice hull passed through 0.5 mm screen) to water of 5:3:3 (g) at 25°C for 3 days. Rhizobium sp. (0.48 g per 80 g seeds) was either applied on seeds just before planting or incorporated in matriconditioning. Results of the laboratory experiment showed that matriconditioning alone or matriconditioning plus Rhizobium sp. (biomatriconditioning) applied to seeds harvested at 122 or 125 dap improved seed viability (percent of germination) and vigor (speed of germination and index of vigor). However, there was no interaction between the two factors in the field experiment. Seeds treated with matriconditioning plus Rhizobium sp. or harvested at 125 dap showed the best improvement in plant growth (plant height) and yields (number and fresh weight of pods).