Evaluating sweet potato tolerance to aluminium toxicity: Comparison of rapid test method and field results

Abstract

Sweet potato cuttings of seven genotypes were grown 6 days in 1.5 mM CaCl2, containing 0.03, 0.06 or 0.12 mM Al as AlCl3 acidified to pH 4.3 with HCl. Both Al level and plant genotype affected maximum root length. The total storage root production for the genotypes was measured in a field experiment where soil pH (0.01 M CaCl2) ranged from 3.2 to 4.5. Root yield showed a positive linear response to soil pH. Of the four highest-yielding genotypes (production of 18,000 kg ha-1 or above at pH 4.2), SPV 80 showed the greatest sensitivity to soil acidity. For these genotypes there was a statistically significant correlation between field experiment regression slope and the ratio of root length in 0.06 mM Al solution to root length in 0.03 mM Al solution (R2 = 0.94 ). Low ionic strength solutions can be used to identify Al-sensitive sweet potato germplasm saving time and space compared to field evaluation