Diversidade e estrutura genética de clones e em populações seminais de Teca no estado de Mato Grosso

Abstract

Teak is a tropical forest species and its plantations are on the rise in the world market, due to the peculiar beauty and quality of its wood. In Brazil, there is a lack of research to make breeding programs of this species viable. Thus, in order to generate information in this regard, firstly, microsatellite molecular markers (SSR) were evaluated to be used in the process of protecting teak cultivars and also, through these markers, kinship relationships and genetic diversity were studied. among 50 commercial or test clones of the species made available by two forestry companies in the state of Mato Grosso. The clones were divided into two groups (referring to each of the companies) with 25 individuals to carry out the analysis of kinship and genetic diversity. Of the 24 primers tested, 20 generated high content of polymorphic information (PIC) and a satisfactory amplification pattern. Based on the probabilities of identity (PI) and exclusion of paternity (PE), a minimum number of four SSR markers capable of detecting polymorphism between individuals was identified. With the analysis of coancestry it was possible to determine clones and possible clones between and within the groups. Among the groups, similar numbers of mean and total alleles per locus were found, as well as estimates of expected (He) and observed (Ho) heterozygosity (Group 1: He = 0.72 and Ho = 0.60; Group 2: He = 0.75 and Ho = 0.63). The genetic differentiation between groups (= 0.02) was low. Through Nei's genetic distance estimates, it was possible to identify three groups among the clones, with a genetically distinct group, formed by only one individual. With these results it is possible to indicate molecular descriptors effective in distinguishing teak individuals for cultivar protection processes and the possibility of developing breeding programs aimed at increasing genetic diversity with these materials, as well as the creation of clones. Subsequently, in the second chapter, the objective was to estimate the diversity and genetic structure of different seminal and clonal populations of teak present in the state of Mato Grosso using ISSR markers. 31 primers were tested on 113 individuals separated into nine populations. Six primers were selected to perform the analyzes, with 55 amplified locus and considered efficient for the characterization of diversity, based on Pearson's correlation and Kruskal stress. All ISSR primers obtained high content of polymorphic information. A percentage of polymorphic locus from 50.9 to 90.9% was detected, with diversity ranging from 0.21 to 0.33 and Shannon's index from 0.30 to 0.49. Most of the genetic diversity observed was within populations (86%). Four genetic groups were identified, formed by genetic materials from Africa, India and Brazil (from Tenasserim). Thus, there is potential genetic diversity that can be explored in future breeding programs, in order to make it possible to increase the species' productivity.