Reproductive shoots of Berberis microphylla G. Forst. in relation with the floral bud development and the fruit set

The objective of this research was to study the reproductive shoots of Berberis microphylla G. Forst. in relation with the floral bud development and the fruit set among and within three populations of Tierra del Fuego during three consecutive years. Evolution of the different reproductive phenological phases of B. microphylla was in accordance with the climatic conditions of the sites and the years, in particular with the temperatures of the end of the winter and beginning of the spring. In fact, blooming period in US was advanced compared to FL and CI populations. Also, full bloom was shorter in US respect to FL and CI populations when the temperatures increased gradually as occurred in 2014 year. The development of reproductive shoots was significantly affected by the population, the shadow and the growing season. Mixed bud number/length was highest in US population; however fruit set was maximum in FL population. Shadow levels of 50% decreased total bud number, total bud number/node number, mixed bud number, mixed bud number/length and fruit number/length. Ultimately, mixed bud number, mixed bud number/length and aborted flowers were maxima in 2015–2016 growing season. The obtained results confirm the presence of phenotypic plasticity of the reproductive shoots of Berberis microphylla G. Forst. in relation with the floral bud development and the fruit set.