Ecofisiologia, modelagem e desempenho agronômico de Helianthus annus L. e Limonium sinuatum Mill. como flores de corte

Abstract

Brazilian floriculture is a promising and typical activity of family farming, which grew at an average rate of 12% per year between 2012 and 2023. It is an activity aligned with the needs of global agricultural production, which faces the challenge of increasing productivity without expanding cultivated areas. The Covid-19 pandemic brought numerous losses to this sector, causing an intense period of vulnerability. A key issue is how to strengthen the entire Brazilian production chain of flowers and ornamental plants on a national scale to face future uncertainties. Could this be achieved by making improvements that align with international market trends, from production to marketing? In this regard, there are two possible paths. One is through local production and trade, which reduce costs and promote domestic consumption of flowers. This modern floriculture model is popular in European and North American countries, and in Brazil, it is a path that has already been pursued and has been consolidated with the "Flowers for All" Project, the largest inclusive floriculture extension project in Brazil. The other path is to develop innovation and generate cutting-edge technologies for floriculture, creating models that simulate the development of flower species. Together, these paths have the potential to consolidate sustainable and successful growth for Brazilian floriculture and increase Brazil's participation in the international market for flowers and ornamental plants. Combining these strategic approaches, field trials were conducted in various regions of Brazil and in the Tuscany region of Italy to deepen understanding of the ecophysiological processes governing the development of two cultivated species as cut flowers: sunflower and statice. Thus, this thesis is divided into three chapters with the following objectives: i) evaluate the growth, development, and production of cut sunflowers in tropical, subtropical, and temperate environments; ii) estimate the phyllochron in field-grown cut sunflower genotypes considering various locations and sowing times to estimate the phyllochron using a single and a bilinear model in field-grown cut sunflower genotypes considering several sowing dates in tropical, subtropical, temperate locations, and; and iii) describe the flowering pattern of the statice crop in the subtropics of Brazil, investigating factors that influence its reproductive phase. The cut sunflower genotypes used in this study are well adapted to tropical, subtropical, and temperate environments, despite variations due to different environmental conditions. The number of leaves and thermal time in cut sunflowers show a bi-linear relationship, resulting in two phyllochrons. The harvesting period of statice can vary from 5 to 18 weeks, and flower yield and production components vary each harvesting week. The results provide important information to flower producers about the environment and its effects on ecophysiological processes in cut sunflower and statice cultivation, forming a solid foundation for the future development of developmental simulation models based on these species.