Plant breeding of Coriandrum sativum from landraces collected in Alentejo (Portugal)

Coriandrum sativum L. (coriander) represents more than 70% of the cultivated area for fresh herb consumption in Portugal. The main goal of this work is to value the traditional germplasm of coriander from south Portugal (Alentejo), through the selection within the landraces with the greatest agronomic potential, for subsequent submission to the Portuguese’s National Catalog of Varieties (NCV). The collection of landraces seeds began in 2000 throughout Alentejo. Morphological variability was observed by germplasm characterization, as well as higher vegetative plant biomass production of some landraces. The selection program started in 2015. The goal was to reduce the variability within each landrace in selection, and obtain plants with high production of basal leaves, high fruit production per plant and large fruit size. Between 2019 and 2021, more than 250 segregation lines, belonging to six landraces, have been tested and selected, annually. The descriptors were: basal leaf density, flowering date, anthocyanin stem pigmentation, plant height, fruit weight per plant and fruit size. An evolution toward plants with greater density of foliage and larger fruits was achieved. The contribution to the improvement of coriander traditional use was achieved with a consistent increase in foliage density and high uniformity of each landrace: coefficient of variation (CV%) below 10% in the last year. The contribution for the fruit industrial use was done by a consistent increase in fruit size, although a considerable variability remains (coefficient of variation between 19.8 and 28.7% within each landrace). In December 2021, 3 lines were proposed to the NCV, from CS1, CS28 and CS32P landraces. The future breeding program will use dynamic selection criteria, suited to the purpose for which the variety is intended: leaf production, fruit yield or essential oil content and composition.