Simple mass screen differentiating traditional rice varieties for tolerance to drought at seedling stage
2015
Valida, G.D. | Cabusora, C.C. | Desamero, N.V.
A greenhouse mass screen of 56 traditional varieties (TRVs) for drought tolerance at seedling stage was conducted in 2013 DS. The mass screen system consists of paddy soil contained in G1 trays measuring 3 m length x 1 m width x 20 cm height or wooden trays measuring 2.86 m length x 0.77 m width x 20 cm height. Rows 10 cm apart were carved along the width of the tray where 50 pre-germinated seeds per entry were seeded approx 2 cm apart. PSB Rc14 and NSIC Rc222 were included as tolerant check, and IR64 as susceptible check. Drought was imposed by withdrawing irrigation water 14 days from seeding until IR64 recorded leaf drying score of 7. Leaf rolling and drying scores during drought development were recorded for all entries. The soil moisture dynamics was monitored using gravimetric method, with 2-day interval soil sampling. The soil moisture was reduced to 5-7% at the end of stress period. The trays were re-watered to release the plants from 11-13 days stress. Plant recovery, vigor and biomass production 10 days after re-watering were recorded. Plant recovery of the TRVs ranged from 0% to 66.4% compared with 42.7% to 61.8% of the tolerant check PSB Rc14. The TRVs produced 0 to 9.6 g biomass per linear row while PSB Rc14 had 4.4 to 6.1 g biomass produced. The system identified TRV Payakan (Collection No. PRB000152) as the most robust entry. Payakan recorded 5 and 3 compared with 7 and 5 leaf drying and vigor score, respectively, of PSB Rc14. It also recorded 7% and 82% higher plant recovery and biomass, respectively, than PSB Rc14. It is also note worthy to mention TRV Aringay with leaf drying and vigor score of 5 compared with score of PSB Rc14, and plant recovery 11% higher than PSB Rc14.
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