Banca de DEFESA: THAISE DA SILVA SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: THAISE DA SILVA SOUZA
DATA: 23/08/2021
HORA: 13:30
LOCAL: On line - Google Meet
TÍTULO:

Potential for use of polyploid Eucalyptus clones in breeding programs

PALAVRAS-CHAVES:

Eucalyptus breeding, polyploidy, wood quality, cytogenetics, quantitative genetics.

PÁGINAS: 15
GRANDE ÁREA: Ciências Biológicas
ÁREA: Genética
RESUMO:

The induction of polyploidy in Eucalyptus can contribute to generating more productive, better adapted, and higher-quality clones. Therefore, this may be one of the alternatives to boost eucalypt breeding in Brazil, since additional gains through conventional plant breeding will be more difficult. After artificial polyploidization, it is essential to certify the effectiveness of the process through cytogenetic analyzes that include chromosome counts and quantification of nuclear DNA. Another alternative to confirm chromosomal duplication is the evaluation of anatomical and morphological characteristics, such as stomatal analysis, measurements of the leaf area, and wood anatomy studies. Besides, the confirmation of the clone performance in field conditions is essential to validate the importance of this technique. In this context, this study aimed to evaluate the potential for use of polyploid Eucalyptus clones in breeding programs. Clones of Eucalyptus grandis x Eucalyptus urophylla artificially polyploidized by Suzano SA were evaluated. Wood samples from these hybrids were used to determine moisture content, basic density, and fiber size. Synthetic polyploid clones of eucalypt presented lower basic density, fibers with higher length, and wall thickness when compared to diploids. Chromosomal counts and DNA content were performed and both evidenced the confirmation of polyploidization, and mixoploidy. The analysis of anatomical and morphological characteristics from leaves of the evaluated clones showed that polyploids had a higher stomatal diameter than diploids and leaf area increased significantly as a function of the clones' ploidy level. Measurements of DBH (diameter at breast height) and MAI (mean annual increment) of three-year-old trees were evaluated and the analyzes allowed to identify more adapted and stable clones, although in most cases the performance of polyploids was lower than diploids in field conditions. The performance of polyploid clones was not affected by the performance of their diploid. These results indicate that the potential for use of polyploids in eucalypt breeding for pulp and paper production in Brazil is promising, although there is a need for more studies to answer the questions that remain.

MEMBROS DA BANCA:
Presidente - VANIA HELENA TECHIO (Membro)
Interno - MAGNO ANTONIO PATTO RAMALHO (Membro)
Interno - GIOVANA AUGUSTA TORRES (Membro)
Externo à Instituição - FABIANA REZENDE MUNIZ - ESALQ (Membro)
Interno - EVANDRO NOVAES (Suplente)
Externo à Instituição - Alexandre Alves Missiaggia - ESALQ (Suplente)
Externo à Instituição - AURELIO MENDES AGUIAR - ESALQ (Membro)