PACLOBUTRAZOL EFFECTS ON FLOWERING OF 'GOLDEN NUGGET' LOQUAT: PRELIMINARY RESULTS

Loquat (Eriobotrya japonica Lindl.) blooms in autumn forming apical panicles after a short summer rest. Deficit irrigation during summer has been proven highly successful in imposing earlier bud rest and hence in advancing blooming date. With the aim of reproducing some of the beneficial effects of summer water deficits, we have explored the effect of soil applications of paclobutrazol on ‘Golden Nugget’, a vigorous genotype with limited response to deficit irrigation. The experiment was carried out during two consecutive seasons (2012 and 2013) on ‘Golden Nugget’ adult trees grafted on BA-29 quince in an orchard located in El Ejido (Almería, Spain). The results show that paclobutrazol when applied in June (soon after harvest) twice to the soil at a split dose of 0.2 g/m² (4 L/ha) was able to slightly advance apical bud summer rest onset and release. The effects were, however, negligible on blooming dates. Later applications of paclobutrazol (in July) were completely unsuccessful in modifying ‘Golden Nugget’ reproductive cycle. The results show that shorter, more compact panicles were formed in the trees treated with paclobutrazol. More flowers per panicle of similar size (estimated by their dry weight) were also produced in trees treated with paclobutrazol. Our results are discussed in the context of apical bud dormancy establishment and release.