Combined effect of rootstocks and uniconazol-p application via irrigation on the canopy of 'Hass' avocado trees

In Chile, avocado cultivation has incorporated the use of uniconazol-p via irrigation in plantations where rootstocks from seed predominate. This study suggested that the effectiveness of applying uniconazole-p to the soil base of 'Hass' avocado trees depends on the origin of the rootstock. Nine-month-old 'Hass' trees were used in Duke 7 clonal rootstock and Mexícola rootstock from seed, together with 0, 0.0035, 0.007 and 0.014 g·L^-1 uniconazol-p. Measurements were made in the canopy of the plants, at the level of vegetative growth, bud development and earliness in flowering. It was found that the differences among variables were at rootstock level; Duke 7 showed greater vigor and earlier flowering than trees with Mexícola. In addition, Duke 7 had no response to the application of uniconazol-p, contrary to what was presented by Mexícola, where the uniconazole-p concentration above 0.007 g·L^-1 showed no effect on either shoot length or the proportion of potential flower buds in relation to the total number of buds.