Germination and physiological maturity of Rubus fraxinifolius seed

Abstract

Seed quality reaches maximum at physiological maturity, characterized by seed vigor. The information on the first and final counts for germination test are necessary to determine physiological maturity of R. fraxinifolius. The information is important for developing and improving seed production and wild raspberry conservation, especially in Indonesia. This study was conducted at Cibodas Botanical Garden and Seed Physiology and Health Laboratory of IPB University from January to July 2023. Two experiments were conducted, with seed treatment and germination methods as factors in the first experiment and fruit harvest age as the factor in the second experiment. From the result can be determined the first and final counts of seed germination test at 39 and 65 days after the plant, respectively. The highest germination percentage, vigor index, and speed of germination were achieved with seeds treated with 1000 ppm KNO₃ using pleated paper, with a germination percentage of 82.5%, vigor index of 27.5%, and speed of germination of 1.94%/day. Physiological maturity was reached at 39-40 days after anthesis, from a fully ripe fruits with a red color and easily falling from the pedicle, have maximum seed dry weight of 0.194 g, germination percentage of 95.8%, and vigor index of 71.6%.