Tolerance to iron deficiency of lupins grown on calcareous soils

Abstract

Lupins differ in their efficiency to utilize Fe3+ in soils containing CaCO3. Most lupin species are susceptible to Fe deficiency. The objective of this study was to screen different lupin species, including introduced cultivars and wild types collected in Israel, for susceptibility to Fe deficiency. In a greenhouse experiment, inoculated seedlings, 7 to 10 days old, were planted in 1 L pots filled with a mountain rendzina soil from Emek Haela (pH=7.3, CaCO3- 45%), or with a brown-red sandy-loam soil from Rehovot (pH=7.7) not containing CaCO3. On the calcareous soil, susceptible lupin plants from day 7 onward showed various degrees of chlorosis, suggesting Fe deficiency, which at a later stage caused reduction of growth, necrosis of the leaf tissue, leaf abscission and ultimately death of the plants. Soil application of FeEDDHA resulted in an immediate remedy of the deficiency symptoms. No deficiency symptoms were observed on plants growing on the sandy-loam soil lacking CaCO3. Ranking of lupins based on visual symptoms of Fe deficiency and on chlorophyll concentration of young leaves relative to their tolerance to soil lime was as follows (location of source plants in brackets). Very good: Lupinus pilosw (Emek Haela), L. cosentinii cv. Erregulla and L. angustifolfus cv. Yorrel. Moderate L. angustifolius cv. Illyarrie. Low L. palaestinus (Gesher Haziv), L. albus cv. L221, L. angustifolius (Gesher Haziv). Very low: L. angustifolius (Givat Brenner), L. palaestinus (Rehovot). The need for further exploration of wild lime-resistant genotypes is emphasized.