Caracterização morfoagronômica e respostas morfofisiológicas de acessos de Urena Lobata L. cultivados em ecossistema de terra firme no Amazonas

Abstract

Mallow (Urena lobata L.) has high socioeconomic importance in the Amazon, being primarily used for fiber production and showing potential as a forage resource. However, limitations related to genetic variability and agronomic management restrict the expansion and efficiency of this crop. Therefore, this study aimed to integrate the morphoagronomic characterization with the evaluation of morphophysiological responses of mallow accessions under different cutting periods. Qualitative and quantitative morphological descriptors, phenological stages, seed production components, morphophysiological variables, growth indices, photosynthetic parameters, and nutritional and bromatological attributes were evaluated. The results showed that, although the accessions exhibited similarities in several morphological traits, they differed markedly in attributes related to vegetative growth, crop cycle duration, and agronomic performance. The accessions displayed low phenological variation during the vegetative phase but greater divergence during the reproductive phase, resulting in differences in total cycle duration. The IRN accession stood out for its shorter cycle and greater vegetative growth, whereas the other accessions exhibited longer cycles and differences in biomass partitioning among plant organs. Delayed cutting resulted in greater biomass production, while early cutting promoted higher nitrogen and crude protein contents, reflecting the dilution effect of these constituents as plant development progressed. Morphophysiological evaluations revealed distinct responses among accessions and cutting periods, with no marked changes in photosynthetic parameters. Overall, the results indicate the existence of accessions with high potential for both fiber production and forage use, highlighting the versatility of Urena lobata L. and reinforcing the importance of this species as a strategic alternative for strengthening the mallow production chain in the Amazon.