Emily Burguêz da Silva

This work explores polyploidy and its significant implications for plant genetic improvement. Polyploidy, which is characterized by the presence of multiple sets of chromosomes, is an essential evolutionary force that impacts the evolution of plant species. This phenomenon is associated with several advantages, such as greater genetic diversity, vigor and resistance to abiotic and biotic stresses, making it crucial for the development of more productive cultivars adapted to adverse conditions. The study reviews methods of polyploidy induction, including physical, chemical, and biotechnological techniques, and discusses their practical applications, such as in the production of seedless fruits and in increasing biomass. In addition, it addresses the challenges and future prospects, highlighting the need for more research to fully understand its genomic and phenotypic consequences. It is concluded that the exploitation of polyploidy is vital to meet the growing demand for food and face climate change, providing new opportunities in the improvement of several species, including ornamental and medicinal, expanding their economic and ecological potential.

A alternative to producing litchi (Litchi sinensis Sonn.) seedlings is by cuttings. However, the main drawback of using this method is related to the difficulty of rooting presented by this species. Thus, the objective of this study was to evaluate the rooting of semihardwood cuttings of litchi ‘Bengal’ at different concentrations of indolebutyric acid, with or without incision in the base. The experimental design was completely randomized with five replicates of 10 cuttings in a factorial 3X2 (three IBA concentrations: 0, 1.000 and 2.000 mg L-1; with or without incision in the base). After 126 days, the variables evaluated were: cutting survival, leaf retention, cutting with callus not rooted, rooted cutting, number of roots per cutting, length of major roots per cutting and dry weight of roots per cutting. For rooting, the IBA application was efficient only when the cuttings were not injured. In addition, there was no influence of the types of cuttings in the IBA concentrations. However, in those with incision at the base, the means were higher without the application of the plant growth regulator. Thus, the 'Bengal' litchi can be multiplied by semihardwood cuttings with incision at the base of the cuttings, without the use of IBA.