Variation in aluminum tolerance among and withinlotuslines

Abstract

Previous studies with one cultivar of each of two Lotus species showed that L. pedunculatus cv. Grasslands Maku is Al‐tolerant while L. corniculatus cv. Maitland is Al‐sensitive. However, little information exists on the relative Al‐tolerance of other lines in these species or on the variability within lines in response to Al. Two solution culture experiments were conducted to study these aspects. The Al tolerance of Grasslands Maku was confirmed, plant dry mass increasing by > 40 % with 10 to 30 μM monomeric Al in solution. In contrast, the yield of Maitland was decreased by > 80 % at 30 μM Al, as was that of the other two L. corniculatus lines tested, AT‐I and AT‐U. The F1 of a cross between a L. pedunculatus line and a L. corniculatus line (G4712) was intermediate with respect to Al tolerance. Also, there was a wide range of response to Al in the F2, which appeared to have similar morphological characteristics to Maitland. Thus, there would appear to be considerable benefit in selecting for Al tolerance and good agronomic characters in this interspecific cross.