Floral and fruit characteristics of blackberry cultivars, and in vitro germination of their pollen grains

Abstract

The objective of this work was to evaluate the floral and fruit characteristics, pollen grain viability, and seed germination capability of blackberry cultivars. The cultivars Brazos, Caingangue, Cherokee, Choctaw, Comanche, Guarani, BRS Tupy and Ébano were evaluated. A completely randomized experimental design was used, with the eight cultivars and ten replicates. Evaluations were made for: number of stamens, carpels, petals, and sepals; basic composition of the culture medium; number of pollen grains per anther, and per flower; germination rate of pollen grains; percentage of fruiting; fresh biomass, dimension, and number of fruit seeds; mass and dimension of drupets; and percentage of seedling emergence. The established culture medium for the cultivars was added with 90 g L^-1 sucrose and 400 mg L^-1 boric acid, with adjusted pH to 6.5, and solidified medium with 8 g L^-1 agar. 'Caingangue', 'Ébano' and 'BRS Tupy' showed low‑pollen grain germination. 'Ébano' showed round fruit with few drupets. 'Choctaw' and 'Comanche' had low percentage of seedling emergence. 'Brazos' stood out for most of the evaluated characteristics, and it is considered as a good parent for breeding programs.