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| Author(s): |
José Carlos de Oliveira Junior
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ilha Solteira. 2022-04-05. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Engenharia. Ilha Solteira |
| Defense date: | 2022-02-22 |
| Advisor: | Mario Luiz Teixeira de Moraes; Silvelise Pupin |
| Abstract | |
Eucalyptus major producer, Mato Grosso do Sul state has a restricted genetic base to AEC 144 clone, which implies suitable genotypes search to the region. Therefore, breeding under different selection strategies plays a fundamental role in materials' choice, and require resources and time. Thus, an alternative to reduce time is essential, such as early selection, associated with molecular tools, to evaluate the best recombination between parents and estimate more careful parameters, important for seedlings seed orchards (SSO) formation and provide quality raw material for pulp and wood for sawmills production. The aim of this dissertation was to verify genetic variation in an Eucalyptus urophylla second-generation progenies of Eucalyptus urophylla test (TP2G-TP-EU), for growth characteristics as diameter at breast height (DBH) and height, as for elasticity modulus, considering wood quality for sawmills. Furthermore, the expected gains and genetic diversity with different selection strategies were also evaluated, and also the genetic correlation between DBH and height for early selection, in order to form a second-generation SSO, by indicating best DBH recombinations between selected parents. TP2G-TP-EU was installed in 2016 at Selvíria-MS, from a SSO with 298 progenies. Its experimental design is in randomized blocks, with 23 progenies, 30 replications, one plant per plot, spaced 3 x 1.5 m. Height (m) and DBH (cm) were measured between 2017 and 2021, and elasticity modulus (MOEd) was collected only in 2021, with Treesonic, device capable of measuring standing wood MOEd. Variance components and genetic parameters estimates were obtained by REML/BLUP. Based on individual additive value, expected genetic gains for each selection strategy were estimated (S1 - individual; S2 - between and within progenies and S3 - within). There was a significant difference regarding LRT for the evaluated characters. The highest expected genetic gain for DAP occurred in S1 (6.68%). There was a high correlation between height and DBH, whether at the same or different ages. Individuals' position correlation over PT five years was moderate to high (> 59%), with emphasis between the fourth and fifth year (97%), indicative of potential for early selection practice for a second-generation SSO establishment. 10 best crosses were selected for cloning, as they had DBH with 75% more productivity than average, with 17.7 cm higher than general average (22.83 cm). Difference between strategies was high, without compromising alleles loss as the selection cycles advanced. For wood elasticity model, individual heritabilities were average, indicating potential for this character improvement. In conclusion, individual selection is a good strategy to be applied in this population, presenting greater expected genetic gains, giving advances in breeding cycles. (AU) | |
| FAPESP's process: | 20/02059-6 - Early selection in second generation progenies of eucalyptus urophylla s.t. Blake |
| Grantee: | José Carlos de Oliveira Junior |
| Support Opportunities: | Scholarships in Brazil - Master |