Abstract

The purpose of this research was to evaluate the seed viability of 16 Oryza sativa L. accessions including valuable endangered landraces, a breeder’s line, and an advanced/improved cultivar after 13-14 years of long-term storage. Preservation of seed samples has been conducted ex-situ at low temperatures (-18°C). The germination test (germination energy and total germination) was carried out according to ISTA methods and Kameswara (2006). Furthermore, the following variables were examined: the germination index, root length, shoot length, root-to-shoot length ratio, total seedling length, and seed vigour index. The Pearson correlation coefficient was computed to assess the linear relationship between the vigour index and seedling length. All the sixteen accessions have had a high total germination rate, in the range of 89-100%, hence there is no need for their regeneration. The germination energy and total germination showed statistically significant differences for two rice accessions at P-0.05 and P-0.01. The seed showing a high vigour index produced seedlings with higher growth rates. The Pearson correlation of the vigour index and seedling length was found to be very highly positive and statistically significant (r=0.99, p<0.001). Based on the results obtained, it can be concluded that rice as a botanical species retains high seed viability during the long-term conservation, although there are individual differences between the accessions which are due to the genetic constitution of each genotype.

Key words: gene bank, ex situ storage, rice genotypes, vigour index, seedling growth.