Development in Origanum ssp.: A simple phenological scale to determine thermal time requirements to critical reproductive events

Day length modulates precocity and productivity through its effect on developmental rate in Origanum vulgare ssp.

“…It is known that in Origanum, initiation of the floral transition occurs under increasing day length (Circella et al, 1995;Dudai et al, 1989) but scarce studies demonstrated genotypic variation in this mechanism. In a previous study under natural conditions in Central Argentina, thermal time to full blooming was found to differ among Origanum vulgare subspecies (vulgare and hirtum) and this was associated with a different switch timing to reproductive development (V 3 stage: presence of apical floral buds on the principal stem, (Davidenco et al, 2015) which suggested intraspecific variability in photoperiodic sensitivity.…”

“…("O. Criollo") were selected owing to their frequent cultivation in the study area. Subspecies differ in time to flowering, architectural traits and productivity (Davidenco et al, 2015;Torres et al, 2012). Plants grown from cuttings of 1-year-old mother plants were transplanted in early September in both seasons, and planted in rows spaced at 0.70 m apart with a distance of 0.2 m between plants.…”

“…Development was weekly monitored until full blooming using a phenological scale previously built for Origanum spp. (Davidenco et al, 2015). The stems of each plant were categorized into the proper phenological stage (V 0 -V 3 for the vegetative macrostage, and from R 4 to R 6 for the reproductive macrostage).…”

“…Thermal time (TT, in degree days • Cd) accumulated up to V 3 and R 6 was determined as the summation of the differences between mean daily temperature and crop base temperature (considered as 0 • C; Kintzios, 2002;Thanos et al, 1995). V 3 is the phenological stage where the 50% of plants have apical floral buds on the principal stem and R 6 is the full blooming phenophase (Davidenco et al, 2015).…”

Effects of irrigation management and seasonal stages on essential oil content and biomass of Origanum vulgare L.

“…The 44 control treatment (-19.7 kPa) was run throughout the oregano cultivation cycle, because its matric potential corresponded to the field capacity of the soil. The cultivation stages were defined as follows: whole cycle, which lasted from seedling transplantation to harvesting; vegetative stage, from seedling transplantation to the emergence of the first floral branch; pre-flowering stage, from floral branch emission to full floweropening (Davidenco et al, 2015).…”