Genotypic response of mango yield to persistence of paclobutrazol in soil

Persistence of paclobutrazol and its subsequent impact on the yield of different commercial cultivars of mango, viz. Chausa, Dashehari and Langra have been studied. Results based on 2-year averages indicate that trees treated with 6 g a.i./tree of paclobutrazol recorded maximum yield in Chausa and Langra, whereas only 4 g a.i./tree was most effective in Dashehari. The application of paclobutrazol, at half the above doses, was effective in inducing flowering as well as fruiting in the third year, but only in cv. Dashehari; still substantially higher yields (47.30 kg/tree) were recorded over control (26.20 kg/tree), but not so in cvs. Chausa and Langra. The trees which were not given paclobutrazol treatment in the third year showed residual effect only in cv. Dashehari, while cvs. Chausa and Langra did not show any residual response. The paclobutrazol residue in the soil collected during the third year from the root zone of trees was in the range of 0.4898-1.0005 μg/g by gas-liquid chromatography.