An experiment was conducted during 1991-2006, at Kerala to evolve dwarfism in cashew (Anacardium occidentale L.) through irradiation. The variation was induced by irradiating 'Madakkathata 1' cashew seeds by gamma-rays at 10, 20, 30 and 40 kR doses using Cobalt-60 source. Induced-dwarfism was noticed in nursery stage. However, this dwarfism did not persist in the field. The regular data recording was abandoned, therefore, by first year itself (1992) till 5th year of tree-age (1996-97) until they started fruiting economically. Thereafter it could be realized that of these variants in field, though none are dwarf, two variants exhibit better nut-weights (12-20 g). Data from 1998-2006 depicts a promising mid-season variant (from 'Madakkathara 1') with higher nut-weight (12.5 g), kernel weight (3.34 g), shelling (26.7%) and nut-yield (9.4 kg/tree/year). Another variant recorded the highest nut-weight (20.8 g), though a poor yielder (2.8 kg/tree/year). However, this can be treated as a useful donor plant in the subsequent breeding programmes. In total of 16 variants established in the field (15-yrs age trees), variation induced were in 6 characters namely, flowering season, single nut-weight and total nut-yield, apple size, shape and colour. In addition, an undesirable trait of sterility was also induced in few variants.
