ABSTRACT
Comparative evaluation of drought response in Malaysian fragrant rice genotypes from seed germination to grain-filling

Noraida Mohd Radzi1, 2, Rosimah Nulit1*, Mashitah Shikh Maidin1, and Mohd Hafiz Ibrahim1
 
Drought has reduced rice (Oryza sativa L.) production and impacted worldwide food security. Malaysian Agricultural Research and Development Institute (MARDI) has developed 58 of rice cultivars including fragrant rice. However, little has been studied about drought tolerance of Malaysian fragrant rice. Therefore, the study was conducted to assess drought tolerance level of selected MRQ rice cultivars. Seeds of rice cvs. MRQ50, MRQ74, MRQ76, Wangi88 and MRQ104 were germinated under three different osmotic stress conditions of control (0 MPa), moderate (-0.6 MPa) and severe (-0.9 MPa) induced by polyethylene glycol (PEG) 6000 for 2 wk to evaluate the drought tolerance at early stage. Thereafter, germination percentage (GP), germination index (GI), germination energy (GE), germination rate (GR), seedlings growth traits including seedling height, fresh weight, dry weight, seedlings vigor I (SVI) and seedlings vigor II (SVII) were evaluated. Plant height, number of tillers, weight of 1000 grains, plant biomass was measured for determination of drought tolerance level at vegetative and reproductive stage. The results indicate that increasing drought intensity significantly reduced germination traits and seedling performance, being MRQ104 the most effected. Under severe drought stress (-0.9 MPa), MRQ74 maintained 90% GP and 85% GR, whereas MRQ104 decreased to 50% GP with complete inhibition of GR (0%). Drought condition at vegetative and reproductive stages demonstrated reduction of most parameters. Drought stress reduced 1000 grain weight in all genotypes up to 25%. Cluster analysis shows that MRQ50, MRQ76, Wangi 88 and MRQ74 were classified as drought-tolerant cultivars while MRQ104 was classified as drought-sensitive cultivar.
Keywords: Fragrant rice, germination, Oryza sativa, seedling.
1Universiti Putra Malaysia, Faculty of Science, Department of Biology, 43400, Serdang, Selangor, Malaysia.
2Universiti Teknologi MARA (UiTM), Faculty of Plantation and Agrotechnology, Jasin Campus, 77300 Merlimau, Malacca, Malaysia.
*Corresponding author (rosimahn@upm.edu.my).