Abstract:
Most of the Sri Lankan traditional rice varieties have low seed
germinability. Seed quality can enhance using seed-priming. Traditional
rice varieties; Kaluheenati, Kuruluthuda, Maawee and Madathawalu were
used. Distilled water and three (100, 50 and 25%) concentrations of
commercially available neem seed extract was used for priming for 24, 48,
and 72 hours. Primed seeds were dried at ambient laboratory conditions for
24-hours. Then, seeds were pre-soaked in water for 0, 24, 48, and 72 hours.
Germination and vigour of primed and unprimed (control) seeds were tested
using paper-towel method and seedling emergence, using four replicates of
100 seeds. Arcsine transformed data were analyzed with one-way ANOVA.
Microbial growth from unprimed and neem-primed (NP) seeds on agar
plates was determined. Germination percentages of unprimed Kaluheenati,
Kuruluthuda, Maawee and Madathawalu seeds (i.e. 62, 32, 24, and 20,
respectively), were increased after 50% NP for 24+ 24 hours presoaking(
83%), 25% NP for 72+ 24 hours pre-soaking(64%), 25% NP for
48+ 48 hours pre-soaking(49%) and 100% NP for 72+ 48 hours presoaking(
55%), respectively. Similarly, seedling emergence of the unprimed
seeds of the same four varieties (65, 10, 12 and 40%, respectively) was
increased with the same treatments by 83%, 25%, 30% and 53%,
respectively. Aspergillus spp., Rhizopus spp. and several gram-negative and
positive, catalase-positive bacteria cocci were isolated from seeds of study
the four varieties studied. NP has enhanced the seed quality of the four rice
varieties studied. Observed reduction of microbial contamination of seeds
after NP could be the reason for observed improvement of seed quality.
