Carrot seed germination and vigor in response to temperature and umbel orders

Abstract

Several factors may influence carrot (Daucus carota L.) crop establishment. High temperatures (35 -40°C), for instance, may delay or inhibit carrot seed germination in the field and so compromise the stand establishment. Carrot seeds from superior umbel orders usually have better physiological quality than those of lower umbel orders. These seeds from superior umbel orders may also show a better performance in adverse conditions. In addition, seeds from different ages show differences in vigor, which affect the stand establishment, mainly under adverse conditions. The aim of this study was to verify the germination at high temperatures and the carrot seed vigor of different umbel orders of 'Brasília', as well as the different 'Alvorada' seed lots. Preliminarily, 'Brasilia' seeds were incubated at temperatures ranging from 20 to 36°C. Also, seeds from the primary, secondary and tertiary umbel orders harvested separately from a basic seed production field and seeds from lots harvested in 1998, 1999 and 2000 were analyzed to the following tests: germination at 20°C (optimum) and 35°C (adverse), accelerated aging, cold test, seedling emergence in greenhouse and mass of 100 seeds. High temperatures reduced carrot seed germination. Seeds germinated better at 20°C than 35 or 36ºC. Seeds from primary and secondary orders, as well as less aged seed lots, had higher vigor and germination at high temperature.

Biochemical and physiological analysis in carrot seeds from different orders of umbels

“…Emergence rate revealed that the time required for the seeds to express their maximum capacity for germination was five days in seeds from the primary umbels, and seven days in seeds from the tertiary umbels. This result agrees with Pereira, Nascimento and Vieira (2008), who stated that seeds from the primary umbels display superior physiological quality when compared to the remaining orders. Biochemical and physiological analysis in carrot seeds from different orders of umbels In analysis of the thousand-seed weight, 0.180; 1,162 and 1,150 g were obtained for the primary, secondary and tertiary umbels respectively.…”

“…High temperatures have a major influence on carrot seed germination, with some cultivars not germinating and others displaying dramatically reduced germination under such conditions PEREIRA;VIEIRA, 2007).…”

Seed Quality and Vigour Assessment of Fennel (Foeniculum vulgare L.) Genotypes

“…The results indicating that most of genotypes with more test weight and size of seed bear better germination percentage, however, this is not true in respect of each genotype. Similarly, Pereira et al, (2008) mentioned that increase in seed germination and development is owing to the higher seed size, weight and density. Seeds with fully mature embryos and high amounts of food reserves are potentially the most germinative and vigorous ones (Carvalho and Nakagawa, 1983).…”

Use of the software Seed Vigor Imaging System (SVIS®) for assessing vigor of carrot seeds

“…Seed vigor can be evaluated by the physiological, biochemical and stress tolerance tests which are commonly used for carrot and other species (Pereira et al, 2008;Chiquito et al, 2012;Kikuti and Marcos Filho, 2013). Computerized image analysis of seedlings has been used for seed vigor evaluation in several species; these are non-destructive methods and can provide objective information in a short period of time with less human interference (McCormac et al, 1990;Marcos Filho et al, 2006).…”