Influence of the season of the year on the embryogenic capability of immature male inflorescences in banano cv. ‘Grande naine’ (<em>Musa</em> AAA)

Abstract

The season of the year is one of the possible factors to consider for taking the initial explants to develop somatic embryogenesis. This work was carried out to determine the influence of the season of the year on the callus with embryogenic structures formation, in the banana cultivar ‘Grande naine’ (Musa AAA) to collect immature male inflorescences are. Male inflorescences were collected for three years, every month. Nodal fascicles closest to the floral meristem were extracted and placed in semisolid medium. The number of contaminated explants and the embryogenic response for each time was quantified, six months after culture. The percentage of microbial contamination and the percentage of fascicles that formed callus with high frequency somatic embryogenesis were calculated using these data. In addition, it the relationship of these variables with the values of average temperatures and precipitations during the three years were also studied. The percentages of contamination were highly variable depending on the season of the year in which the inflorescences were collected in the field (0 - 82.5%). The analysis did not show correlation between embryogenic response and percentage of contamination, in relation to rainfall and temperature values recorded during the three years of research. Embryogenic response ranged from 0-11.5%. Results showed that the season of the year to collect immature male inflorescences did not influence the formation of somatic embryos in this cultivar of banana. Keywords: callus, microbial contamination, high frequency somatic embryogenesis