Morfofisiologia de castanheira-do-brasil como base para propagação por enxertia de garfagem

Abstract

Brazil nut (Bertholletia excelsa bonpl.) Is the main non-timber product produced in the Amazon region and its cultivation has encountered some difficulties, mainly related to the production of its fruits and the perpetuation of the species. One problem for extractivism is its production of seedlings, considering that it takes at least six months to germinate and has a low success rate. Grafting may be a solution to this problem, since the availability of grafted seedlings may favor chestnut cultivation, due to the precocity of production, increased productivity and the quality of the nuts, and the reduction of the size of the trees facilitating the collection of fruits and cultural dealings and the guarantee that the producer has that is bringing quality material to the field. The success of the technique is directly related to the quality of its graft portal. For this purpose, the morphometric variables of 240 plants, stored in different containers and coming from two ages, were collected, obtaining data on plant height, number of leaves and leaf area, number of branches and diameter of the collection. In addition to the physiological variables, such as chlorophyll A and B, readings with fluorometer, luminosity and temperature. The technique chosen was the grafting at the top in a full slit, with a completely randomized design with 240 plants, performed in the greenhouse of Embrapa Agrossilvipastoril. The rootstocks were derived from seminal planting and the graft was collected from a 17-year-old grafted matrix tree at full productivity. The analyzed variables were the morphophysiological data collected from the porta graft, the grafting glue and the relationship between both. As a result, it has been found that the container affects the development of the seedlings, it being preferred to work with larger volumes. The plants were under stress caused by the inability of the root system to grow, as well as by the residence time too long in the containers. The grafting index even within the same diameter classes was low. The technique of grafting by grafting is very promising in several species, requiring continuity in the studies and new attempts with the chestnut tree to know which methodology and season are suitable for the species.