Stigmatic receptivity and pollen viability of theobroma subincanum mart.: Fruit species from the amazon region

Abstract

Theobroma subincanum (cupuí) is a fruit species native to the Amazon region. Fruits are enjoyed by local people and consumed both as fresh fruit such as juice, nectar or soft drinks. Reproductive biology studies provide contributions to conservation strategies and plant improvement. The present study aimed to analyze the stigmatic receptivity and pollen viability of T. subincanum. This study was developed in a forest fragment located in the urban perimeter of the municipality of Alta Floresta, MT. In the flowering period, flower buds or flowers were collected in seven different times, as follows: 10 pm, 02 am, 06 am, 10 am, 2 pm, 6 pm, and 10 pm. Pollen viability was estimated by reactive Alexander (1969) and stigmatic receptivity using 3% hydrogen peroxide. Pollen viability averages were submitted to analysis of variance, while stigmatic receptivity was analyzed by average percentage in each interval. Four floral stages were characterized based on flower opening, and from 6 am, fully opened flowers have already been found (stage IV). The percentage of pollen viability was not affected by collection times. In the stigmatic receptivity analysis, it was observed that in all floral stages, stigma was receptive; however, the highest percentages of stigmatic receptivity were found from 2 am to 10 am of the same day, which is the most propitious time for fertilization. Pollen collection of T. subincanum may be performed in any of schedules evaluated in this study, since it is held with high viability percentage.