Agronomic Response of Four Philippine Soybean Cultivars to Temporary Flooding
at Two Growth Stages
Liezly L. Magdua1* and Eureka Teresa M. Ocampo2
1 Institute of Plant Breeding, College of Agriculture and Food Science, University of the Philippines Los Baños, College 4031, Laguna, Philippines; 2 Institute of Crop Science, College of Agriculture and Food Science, University of the Philippines Los Baños, College 4031, Laguna, Philippines.
*Corresponding author, magdualiezly@gmail.com
Abstract
Soil waterlogging is one of the major environmental stress factors that has a
devastating effect on crop growth. This study was conducted to evaluate the response
of popular Philippine soybean cultivars to waterlogging stress during early season (30
days after planting, DAP) and late season (beginning bloom, R1 stage) flooding.
Response of cultivars to the timing of the stress at 14 d waterlogged duration was
significant for seed yield and seed yield components. Based on seed yield damage
index, PSB Sy1 was the most tolerant genotype followed by the landrace Manchuria;
while PSB Sy6 and PSB Sy3 were most susceptible to waterlogging. The effect on
soybean seed yield of the two waterlogging stress timings was statistically similar. The
number of pods per plant, high percentage of seed-filled pods and the weight of seeds
(per plant) were crucial seed yield components. Flooding stress caused decreases in
root length and shoot dry matter partitioning in susceptible genotypes, whereas the
tolerant PSB Sy1 (across waterlogging treatments) increased its root length, and leaf
and stem-partitioned dry matter. It appears that the flooding tolerance mechanisms of
soybean result in the differences in seed yield components.
Keywords: soybean, cultivar, waterlogging stress, yield components
Vol 45:(1) April 2020