Shoot and root dynamics of open-pollinated and hybrid corn (Zea mays L.) genotypes under two soil moisture conditions
2005
Ibasco, S.Q., Philippines Univ. Los Baños, College, Laguna (Philippines)
Variations in dynamics of shoot and root systems might be linked to differential genotypic capacities to withstand soil moisture deficit. Two pot experiments were conducted to evaluate the root and shoot dynamics of three maize genotypes under two soil moisture regimes. Improved Tiniguib, an open pollinated variety (OPV) and C-818, a single-cross hybrid were used in experiment 1 while G-404 (or Ghen 404), a three-way cross, and C-818 were used in the second (or follow-up) experiment. The open pollinated variety had significantly higher shoot biomass under drought conditions while the single-cross hybrid C-818 had similar shoot biomass under drought and well-watered conditions. Genotype x water regime interaction effect on shoot dry weight involving the two hybrids was not significant indicating that both hybrids had similar shoot biomass dynamics under drought and well-watered conditions. The three genotypes had the largest bulk of their root biomass in the 0-15 cm layer of the soil. Improved Tiniguib had lower root biomass than C-818 in the 0-15, 15-30, 30-45, 45-60 and 60-75 layers of the soil throughout the 20-day soil drying period. G-404 had significantly higher root biomass in the 30-45 cm layer at 21 days after withholding water (DAWW) but had significantly lower root biomass in the 45-60 cm layer at 28 DAWW than C-818. Root biomass was not significantly related to root length and soil moisture content. Hence, root biomass is not a reliable indicator of root absorbing capacity.
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