Floral biology and agronomic evaluation of three hybrids of Portulaca umbraticola (Portulacaceae)

Abstract

Portulaca umbraticola is an ornamental plant of the Portulacaceae family widely used in gardening. The objective of this study was to evaluate the pollen viability, stigmatic receptivity and agronomic behavior of three hybrids of Portulaca umbraticola obtained in 2021, Tekila Sunset, Coral Lipstick and Star Blush in comparison to commercial cultivars pink, yellow and orange from Vigrow Seeds®. Measurements were taken in five quantitative and five qualitative variables for the agronomic evaluation. Pollen viability and stigmatic receptivity were evaluated using 1% acetic carmine staining and with hydrogen peroxide, respectively. Significant differences were obtained in the quantitative variables (p≤0,05), with the commercial cultivars being the largest. In terms of pollen viability, the cultivars with the lowest and highest amount of viable pollen were Coral Lipstick and Tekila Sunset with 17,4% and 91.6%, respectively. There were significant differences (p≤0,05) in terms of cultivars, timing and cultivar × timing interaction for stigmatic receptivity, which was greater in the range of 11:00-3:00 p. m. for most cultivars. Agronomically adapted hybrids with novel coloring patterns were obtained for the ornamental market. In future breeding programs, it is recommended to take as male parents those with the highest pollen viability and carry out pollinations in the time range where the stigma is most receptive.