Internal and external morphology of Tectona grandis Linn F. diaspores and its relation to seed quality

Morfologia interna e externa de diásporos de Tectona grandis L. e sua relação com a qualidade de sementes

ABSTRACT

Bearing in mind the importance of Tectona grandis L. production in Mato Grosso State, Brazil, it is necessary to establish crops with seedlings of excellent quality, and the selection of diaspores can improve seed vigor, thus providing better quality to the seedlings. It was aimed to indicate the ideal stage of maturation of T. grandis diaspores through image analysis, guaranteeing seed quality and seedling production. T. grandis diaspores were collected in the years 2016 and 2017 at 90, 120, 150, and 180 days after anthesis. The material collected was analyzed for the presence of seeds per fruit in X-ray equipment to compose the treatments. After this selection, the variables color, area, and diameter were analyzed, and fruit weight, germination, and emergence tests were carried out. The diaspores along the maturation process, had higher amount of seeds and higher weight. The increase in the colors yellow and black was na indicative of the maturation for T. grandis diaspores collected in 2017, and the reduction of the percentagem of dark gray color for the diaspores collected in 2016. Fruit area and diameter was higher in those who had four seeds and the diaspore quality evaluated by the germination percentage, germination first count, initial stand and emergence percentgevary according to the amount of seeds present in the diaspore, being higher for diaspores containing 4 seeds. Diaspore quality was evaluated by germination percentage, first germination count, initial stand, and emergence percentge, was superior in the 2017, with diaspores having 2 na 3 seeds. The maturation of T. grandis diaspores is dependent of the year of collection and presents better quality when collected at 120 and 150 days after anthesis.

Keywords
Seed image analysis; Maturation; Breaking seed dormancy