Diversity and physiological plasticity of vegetable genotypes of coriander improves herb yield, habit and harvesting window in any season

Coriander (Coriandrum sativum L.) was domesticated at some point of early history and now has no wild ancestors, so collections of accessions in genebanks are the only source of new genes for breeders. For growers of fresh herbs, coriander has proved to be the most problematic among popular herbs: it flowers early, flowering changes the taste of the rosette leaves and the leaves are also susceptible to sudden yellowing. In this paper we show that the use of vegetable genotypes from the subspecies microcarpum (Coriandrum sativum L. subsp. microcarpum DC.) can solve these problems. Accessions were obtained from the Genebank of the Vavilov Research Institute of Plant Industry, Russia. These vegetable genotypes showed a remarkable plasticity of physiological characteristics (time of flower initiation, time of whole-rosette senescence and heat resistance), which ensured a prolonged harvesting window. The vegetable genotypes also showed increase in biomass, number of leaves in the basal rosette and leaf area compared to fruit genotypes. Thus, vegetable genotypes from subsp. microcarpum proved to be an invaluable source of genes for breeders. Our study also extended knowledge on the morphogenesis and ontogenesis of coriander. First, we found that production of leaves in the basal rosette occurs at the same rate in winter and in summer, so does not dependent on season, but can be interrupted by elongation of the flowering stem, which is season-dependent. Second, we found that the time of whole-rosette senescence (yellowing) is an individual characteristic of a genotype, but is promoted by season similar to the flowering-time. Finally, we showed that the whole-rosette senescence (yellowing) occurs independently of the development of flowering stem.