Wild carrot diversity for new sources of abiotic stress tolerance to strengthen vegetable breeding in Bangladesh and Pakistan

Abstract

Crop wild relatives (CWRs) of carrot (Daucus. carota L.) including 64 germplasm accessions of D. carota L. subsp. carota, D. carota L. subsp. capillifolius (Gilli) Arbizu, and D. carota L. subsp. gummifer (Syme) Hook. f., as well as two accessions of another 18-chromosome species, D. syrticus Murb., were grown in field trials to flowering under conditions of heat, drought, and salinity stress in Bangladesh and Pakistan. Plant growth before floral initiation was evaluated and plants were allowed to progress to flowering to evaluate seed production. A wide range of response was observed among entries ranging from no germination or plant death early in development to vigorous growth. Carrot grown under optimal conditions in the greenhouse served as a useful control to estimate tolerance indices in the field. New sources of heat and drought tolerance in subsp. carota and subsp. capillifolius accessions were identified with similar performance in both countries. Ecogeographic analysis demonstrated that environmental parameters at the collection location of germplasm were associated with heat and drought tolerance observed in field trials. Plants evaluated for tolerance were allowed to flower and seed was produced on selected plants with abiotic stress tolerance to develop populations or breeding pools and to initiate the development of carrot better adapted to climatic abiotic stress.