Variability in floral traits and reproductive success among and within populations of Berberis microphylla G. Forst., an underutilized fruit species

Abstract

Berberis microphylla G. Forst. (calafate) is an evergreen and spiny shrub considered as a non-timber patagonian forest product, that is relevant for diversification of agrifood production, particularly interesting since its black–blue fruits are rich in phenolic compounds. The objective of this research is to analyze the variability in floral traits and reproductive success of Berberis microphylla G. Forst. among and within three populations of Tierra del Fuego along three growing seasons. The presence of variability in some floral traits as well as in the reproductive success of B. microphylla among and within three Tierra del Fuego populations was observed, in agreement with the environmental conditions i.e. mean daily temperatures and accumulated rainfall for the three populations and the three growing seasons. Flower dry weight and gynoecium area are good indicators of flower quality (i.e. ovule number), with positive and significant correlations between them (flower dry weight with gynoecium area, r=0.551; p=<0.001, and flower dry weight with ovule number, r=0.407, p < 0.001). Pollen/ovule, seed/ovule, fruit/flower and fecundity indices are also good indicators not only of flower quality but also of the reproductive success. The multivariate analysis allowed to analyze jointly the whole measured variables, and explored the influence of annual climatic variability in the response of plants and populations. The variables with great changes among years were those representing quantities (the numbers of ovules and pollen grains) as well as some of the related with size (gynoecium elongation and pollen grain size). Likewise, the influence of each variable in the population split was highlighted at each growing season, which helps to understand the drivers of the differences among them. Plants with a highlight performance were detected and could be selected for their clonal propagation and ex-situ evaluation for the beginning of a breeding program.