Chiang Mai Journal of Science

     Microcracking (MC) downgrades the quality of tomato fruits (Solanum lycopersicum) because it allows entry of fungi, and reduces the shelf life of the fruits by damaging the fruit cuticle membrane (CM). Recently, experiments were conducted to evaluate the effect of boron (B) defi ciency on MC in tomato fruit. Seedlings of two cherry tomato cultivars ‘Chika’ and ‘Regina’ were grown hydroponically and treated with 0, 5 and 10 mg·L^-1 of B in summer and autumn. ‘Regina’ fruit that were B defi cient showed a higher incidence of MC than fruit treated with B 15 Days After Anthesis (DAA). While no signifi cant difference was observed in ‘Chika’ fruit under the same treatment, we found them to be susceptible to B defi ciency when treated at an earlier stage (0 DAA). In both cultivars, B treatment did not affect CM deposition or fruit size. However, under B defi ciency, MC incidence, and cell enlargement increased, especially in summer, when fruit growth rate was high. This indicates that the additive effects of fruit growth rate and B defi ciency on the CM increased the incidence of MC in tomato fruit during summer.