Abstract
Abstract Agricultural weeds are plants well-adapted to agricultural environments interfering directly and indirectly with crop production and causing important economic losses worldwide. Crop-wild hybridization is one of the main forces that have ruled weed evolution along with adaptation to agricultural (or benign) environments. Considering the competing demands for resources in any plant, adaptation to agricultural environments might result in an increase in growth but with lower tolerance to stress. In Argentina, most of the non-native H. annuus populations grow on roadsides, ditches, fences, hedgerows (ruderals), but there are also a few cases of H. annuus growing in agricultural field as weeds (agrestals). We asume that weediness of these agrestal biotypes came after crop hybridization as result of growth-stress tolerance trade-offs. Ruderal, agrestal (with evidence of crop introgression), and crop biotypes were contrasted under studies of drought and defoliation stresses, as well as for plant growth under non-stressful conditions and sequences of stress-related genes. The agrestal biotype was less tolerant to defoliation and drought than the ruderal biotype. Drought tolerance variation was largely explained by plant height rate (growth) and defoliation tolerance variation was mainly explained by biomass accumulation (resource allocation). Agrestal biotype sequences of two genes encoding transcription factors involved in stress response, DREB2 and NAC, showed evidence of positive selection in the crop direction. Therefore, selection in the agricultural environment combined with crop hybridization driver the evolution of a well-adapted genetic variant of H. annuus with fast growth but reduced stress tolerance.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.