GENETIC EVALUATION OF SEED GERMINATION AND DEVELOPMENT OF SEEDLINGS IN Ormosia excelsa Benth

Abstract

The aim of this study was to estimate the genetic parameters of Ormosia excelsa seeds based on germination traits, at different temperatures, in order to facilitate the selection of superior varieties of seeds for producing seedlings. Twenty six progenies collected in the municipality of Autazes (state of Amazonas, Brazil) were evaluated. The experiment was completely randomized, with four replications and 25 seeds per plot, totaling 100 seeds per progeny. The germination rate, mean germination time and the synchronization and speed germination indexes were determined at the temperatures of 30 and 35 °C. Seedling development was also evaluated under nursery conditions. The progenies of O. excelsa showed significant genetic variability for all traits. Both temperatures proved to be effective in producing germination close to 87%. Germination began between 1 and 4 days after sowing. However, for greater efficiency in the selection of superior progenies, each environment should be considered individually. The high heritability values obtained (> 65%) and the high genetic correlation favorable for selection, among all traits, resulted in significant gains according to the selection process used. Our results indicated that determining superior progenies for height and number of leaves was possible based on a single evaluation. The fact that 100% of seedlings planted in the field survived promotes a promising outlook to set up commercial nurseries for the species.

GENETIC PARAMETERS IN SEED CHARACTERS OF Ormosia discolor UNDER DIFFERENT AMBIENT CONDITIONS

“…Fresh weight ranged between 0.29 to 0.17 g (mean of 0.2 g), length ranged between 9.3 to 6.3 mm (mean of 7.7 mm), width ranged from 8.4 to 6.6 mm (mean of 7.6 mm), and thickness ranged between 6.1 to 4.9 mm (mean of 5.5 mm), demonstrating that the seeds were not uniformly sized (Table 6). For the strong effects caused by the ambient temperature in biometric data, the experimental coefficients of variation are considered satisfactory for this analysis (TOMAZ et al, 2018;NASCIMENTO JÚNIOR et al, 2016).…”

“…discolor is an impervious-tegumented and orthodox species according to the water content and vigor observed in the seeds during germination tests. These characteristics, commonly found in most of the species that are part of the genus Ormosia, are useful for species identification, being known as hard-coated seeds (TOMAZ et al, 2018). Hard-coated seeds are generally orthodox and drying-tolerant, remaining alive with water content of approximately 5 to 7%, withstanding temperatures below zero and remaining viable for many years (GARCIA et al, 2015).…”

“…The results were expressed as mean percentage based on the number of normal seedlings (BRASIL, 2013). According to Tomaz et al (2018), the characters mean germination time (MGT), synchronization index (SI), and germination speed index (GSI) were determined.…”

“…Studies of genetic parameters of the Amazonian tree species O. excelsa in seed germination characters were essential for the selection of superior genotypes (TOMAZ et al, 2018). For the O. discolor species, this information is still inexistent, being crucial to obtain seedlings with genetic and physiological quality (TOMAZ et al, 2018;VECHIATO;PARISI, 2013), besides establishing guidelines and protocols for the selection of superior matrices to form commercial seed lots and assist in the domestication and genetic conservation of the species.…”

Efeito de diferentes volumes e tipos de recipientes no crescimento inicial de mudas de Ormosia excelsa Benth

“…Sua madeira é usada por extrativistas para a fabricação de móveis, bancos e canoas (CAMPOS FILHO, 2012). Apresenta crescimento rápido e por estar inserida em ambiente de igapó, pode ser indicada para a recuperação de mata ciliar (TOMAZ et al, 2018). Quanto a sua distribuição geográfica, ocorre nos estados do Amazonas, Pará, Rondônia Goiás e Mato Grosso (REFLORA, 2020).…”