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Mating system and distribution of genetic variability of Myracrodruon urundeuva (F.F. & M.F. Allemão) in different biomes

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Danilla Cristina Lemos Souza
Total Authors: 1
Document type: Doctoral Thesis
Press: Botucatu. 2017-03-23.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agronômicas. Botucatu
Defense date:
Advisor: Mario Luiz Teixeira de Moraes; Celso Luís Marino

Myracrodruon urundeuva (Anacardiaceae) is a tree species with a wide geographic distribution. Because it has wood of recognized economic value, associated with the high rate of fragmentation of its habitats, it is threatened with extinction. In order to maintain the existing genetic variability of the fragmented populations and reduce losses in the genetic base of the species, M. urundeuva seeds were collected in different regions in Brazil for the formation of the ex situ conservation bank of the Faculty of Engineering of Ilha Solteira (FEIS/UNESP), in Selvíria-MS. This work was conducted with the aims to characterize the mating system and estimate population genetic parameters in M. urundeuva offsprings from different Brazilian biomes, using quantitative growth traits and molecular markers of the microsatellite type. The height, diameter at breast height (DBH), mean crown diameter and survival were used to evaluate five populations: Aquidauana-MS, Selvíria-MS, Itarumã-GO, Paulo de Faria -SP and Seridó-RN. The values high to median observed for survival (96.4% - 70.8%) indicate good adaptation of populations of M. urundeuva and potential for use in reforestation. Estimates of the coefficient of genetic variation ranged from 3% to 24.6%, at the individual level, and from 1.5% to 12.3%, among progenies, with the highest values obtained for the DBH of the Seridó population. The individual heritabilities ranged from moderate (0.41) to low (0.01) for the characters. Using the genetic value of the individuals, DBH was used to estimate genetic gains in the selection of individuals within progenies, and the Itarumã population being the most indicated for breeding, in the said year of evaluation of these populations (Itarumã population at 11 years old). For molecular analysis, 20 microsatellite loci were developed from the new generation sequencing (MiSeq Sequencing System, Illumina), and six of these were used to characterize the populations of Aquidauana, Itarumã, Paulo de Faria and Seridó (1,224 individuals).The total number of alleles (215), the number of different alleles (67) and the observed heterozygosity values demonstrated that these populations still retain considerably high genetic diversity indices. High genetic differentiation was detected among populations (33%), related, in part, the distance separating them; and it was observed that the species dioica M. urundeuva is reproduced by mating. These matings are not random in populations, with increased degree of relationship in populations with strong anthropic pressure. The coancestry coefficients within offspring were higher than expected in half-sibs offsprings (0.125), so these offsprings are also composed of full-sibs. Aiming at the use in reforestation, seed collection strategies should be adopted, in order to avoid obtaining seeds produced from related or inbred matings, establishing the minimum collection amount in 55 seed trees, in each population, so to ensure an effective population size of 150. The informations obtained from this study are useful for the purpose of conservation and breeding of the species, but also for selection of potential matrices for environmental recovery. (AU)

FAPESP's process: 13/24503-1 - Mating system and distribution of genetic variability of Myracrodruon urundeuva (F.F. & M.F. Allemão) in different biomes
Grantee:Danilla Cristina Lemos Souza
Support Opportunities: Scholarships in Brazil - Doctorate