Screening of Rice Cultivars for Tolerance to Al-toxicity in Nutrient Solutions as Compared with a Field Screening Method1
- R. H. Howeler and
- L. F. Cadavid2
Upland rice (Oryza sativa L.) grown on acid soils may suffer serious yield reductions due to Al.toxicity. Field experiments showed that many tall traditional cultivars from acid soil areas required only small lime applications, while most of the new semi-dwarf cultivars required substantial quantities of lime to reach their yield potential. Without or with modest applications of lime, the tail Al-tolerant cultivars consistently outyielded the Al-susceptible semi-dwarf cultivars. Since high lime applications are often prohibitively costly and difficult to incorporate deeply, Al tolerance can be an important characteristic for upland rice cultivars.
Large numbers of rice cultivars were screened in the field for AI tolerance at several lime levels. A more rapid nutrient solution screening method for rice seedlings was developed. The relative rootlengths (RRL) of plants grown at 30 and 3 ppm AI was used as an index of AI tolerance. The RRL values of eight cultivars used as standards corresponded to field observations of their relative tolerance to acid soils. Moreover, the RRL values of 240 cultivars were well correlated with grain yields in the field, obtained at a low lime level.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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