Luminosity and sowing depth in the emergence and development of passion fruit seedlings

Abstract

-The propagation of passion fruit in commercial orchards is carried out by seeds. However, passion fruit seed germination occurs irregularly. The goal of this study was to evaluate the emergence and development of passion fruit seedlings under different luminosities and sowing depths. The experimental design was completely randomized with six replications of 25 seeds, with a 3 x 5 factor scheme, in which three light conditions (absence of light, presence of 12 h light and 12 h dark and the presence of light for 24 h) were combined with five sowing depths (1, 2, 3, 4 and 5 cm). The emergence test was conducted in a BOD-type germination chamber, with alternating temperatures of 20-30 °C, at intervals of 12 h and the established luminosities. The evaluated characteristics were the emergence percentage for weekly counts, the emergence speed index for 28 days; the total shoot and root length on evaluation day 28 and the individual dry weight. The lack of luminosity accelerates the emergence of passion fruit seedlings, but it produces low quality seedlings. However, the alternation of luminosity associated to a lower sowing depth helps both the emergence and the quality of seedlings produced from passion fruit 14 days after sowing.

Photoperiod and temperature on seed germination of passion fruit 'SCS437 Catarina'

“…seeds do not depend on light and dark conditions for germination percentage. And the result is also reinforced by the study by Ribeiro et al (2017), who evaluated three periods of light exposure (0, 12, and 24 h) in P. edulis seeds set to germinate at an alternating temperature of 20/30 ºC, obtained a significant difference in germination between the tested periods of light exposure. The average percentage of emergence was 83, 92, and 86 %, respectively.…”

“…Maciel e Bautista (1997) obtained a higher percentage of germination in dark conditions, with reduced values during exposure to light, and concluded that passion fruit seeds are negatively photoblastic. Ribeiro et al (2017) found that passion fruit seeds exposed to dark periods had higher emergence values compared to those exposed to continuous light or continuous dark, inferring that passion fruit seeds need periods in the absence of light to trigger the process of germination.…”

Biometric characteristics of fruits, seeds and plants of Hancornia speciosa Gomes. (Apocynaceae)

“…Therefore, the success of seed utilization depends on a rapid and uniform emergence of seedlings in the nursery or field (Barros et al, 2010;Vieira et al, 2015). The delay in emergence of seedlings leaving the seeds more vulnerable to attack from predators (pests and pathogens) and unfavorable environmental conditions (temperature, substrate moisture, among others) and, therefore, compromise the establishment of a uniform stand (Silva et al, 2017b;Ribeiro et al, 2017). The cultivation of a native species depends on the technical knowledge, spread and growing environment of this species.…”