RESPONSES OF 2 SOMACLONAL VARIANTS OF QUINCE (CYDONIA-OBLONGA) TO IRON-DEFICIENCY IN THE GREENHOUSE AND FIELD

Somaclonal quince (Cydonia oblonga Mill.) variants IE-1 and IE-2 (Dolc et-Sanjuan et al., 1992) were more tolerant to Fe-deficient renditions in vitro than the original clone Quince A, The tolerance vies evidenc ed by higher chlorophyll concentrations in leaves, higher Fe(III) redu ction in roots, and increased acidification of the medium. In Summers 1993 and 1994, the two variants and Quince A were compared in the gree nhouse, grown in normal potting soil (pH 5) and in soil obtained from an Fe-deficient orchard, with and without the addition of lime and KHC O3 solution to increase the pH (up to pH 8.3) and intensify Fe stress. In both years, the variants had significantly higher leaf chlorophyll concentrations than Quince A when grown in high-pH soils. The Fe+2 co ncentrations in leaves were also higher in the variants, Under field c onditions at IRTA Reus, Spain, IE-1 and IE-2 had higher chlorophyll co ncentrations than the controls at some, but not all, analysis dates. T hese results suggest that IE-1 and IE-2, when grown as young plants in the greenhouse, have higher tolerance to Fe deficiency than Quince A, as observed in vitro, but that the tolerance is more variable under u ncontrolled conditions in the field.