Rice root traits for drought resistance and their genetic variation
1994
Ingram, K.T. | Bueno, F.D. | Namuco, O.S. | Yambao, E.B. | Beyrouty, C.A. (International Rice Research Inst., Los Banos, Laguna (Philippines). Agronomy, Plant Physiology, and Agroecology Div.)
The root traits that confer drought resistance are not well defined. Glasshouse research has shown that the root xylem vessel cross-sectional area does not explain water relation differences across genotypes. In field experiments under upland conditions, root length density (RLD) was negatively correlated with grain yield of three rice genotypes grown under different levels of water deficit stress. On the other hand, in minirhizotron experiments under rainfed lowland conditions, only RLD in the 10-20 and 20-30 cm soil layers were related to relative yields (30-d vegetative phase stress yield/continuously flooded control yield) in 12 rainfed lowland genotypes and only on 2 sampling days (86 and 89 d after sowing). Two root characteristics were common to drought-resistant rainfed lowland genotypes: 1.) rapid root responses to changing soil moisture level in the 10-20 and 20-30 cm soil layers, and 2) greater absolute RLD below 20 cm
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