Fatores gen?ticos e ambientais na emerg?ncia de pl?ntulas de pequizeiro (Caryocar brasiliense camb.).

• Main Author: Rocha, Jo?o Paulo
• Other Authors: Lopes, Paulo S?rgio Nascimento
• Language: Portuguese
• Published: 2015
• Subjects: Pequi; Taxa de emerg?ncia; Prog?nies; Proced?ncias; Produ??o Vegetal
• Online Access: http://acervo.ufvjm.edu.br:8080/jspui/handle/1/536

Submitted by Rodrigo Martins Cruz ([e-mail]) on 2015-02-27T13:30:32Z No. of bitstreams: 5 2.pdf: 984350 bytes, checksum: 04e03f5d860785728cd837db9f0819af (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20626 bytes, checksum: 7851d446050a985bd0603b7c4cee472d (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) === Approved for entry into archive by Rodrigo Martins Cruz ([e-mail]) on 2015-02-27T16:32:20Z (GMT) No. of bitstreams: 5 2.pdf: 984350 bytes, checksum: 04e03f5d860785728cd837db9f0819af (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20626 bytes, checksum: 7851d446050a985bd0603b7c4cee472d (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) === Made available in DSpace on 2015-02-27T16:32:20Z (GMT). No. of bitstreams: 5 2.pdf: 984350 bytes, checksum: 04e03f5d860785728cd837db9f0819af (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20626 bytes, checksum: 7851d446050a985bd0603b7c4cee472d (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) Previous issue date: 2009 === A baixa taxa de germina??o pode ser o principal fator respons?vel pelo desest?mulo ?s pr?ticas de plantios comerciais de pequizeiro (Caryocar brasiliense Camb.). O objetivo deste trabalho foi verificar os fatores ambientais (localiza??o geogr?fica), proced?ncia, prog?nie, ?cido giber?lico e tempo de armazenamento das sementes na emerg?ncia de pl?ntulas dessa esp?cie. Foram coletadas sementes de prog?nies (matrizes) oriundas dos munic?pios mineiros de S?o Gon?alo do Rio Preto, Curvelo e Serro ? distrito de S?o Gon?alo do Rio das Pedras. As sementes foram coletadas em janeiro de 2005 e 2007 para o experimento 1 e em janeiro de 2007 e 2008 para o experimento 2, sendo semeadas em dois munic?pios: Diamantina (ambiente de baixa temperatura) e Curvelo (ambiente de alta temperatura). Os dados foram analisados atrav?s de testes Qui-quadrado para independ?ncia. Para os experimentos 1 e 2, conduzidos em Curvelo, todos os fatores foram altamente significativos (P<0,1%), exceto o efeito de proced?ncia (P = 6,89%) e do ?cido giber?lico (P = 6,08%), ambos do experimento 1. No experimento 1, conduzido em Diamantina, nenhum fator foi significativo a 10%, exceto o tempo de armazenamento (P = 5,64%) e o efeito ambiental (P<0,01%). J? no experimento 2, conduzido em Diamantina, todos os fatores foram significativos a 5%. A n?o signific?ncia para a maioria dos fatores em Diamantina no experimento 1 foi em decorr?ncia da baix?ssima taxa de germina??o nesse ambiente (apenas 11 sementes germinaram, de um total de 2010). A diferen?a de germina??o foi tamb?m significativa entre os dois ambientes - Curvelo e Diamantina, para os dois experimentos. Entretanto, no experimento 2, a germina??o foi menor em Curvelo, contrariando as expectativas. Acredita-se que a ocorr?ncia desse fato seja porque no ano de 2008 a sementeira em Diamantina foi montada no ch?o e n?o suspensa, como em Curvelo. A varia??o t?rmica seria maior no leito de areia suspenso por estar com a parte inferior exposta ? temperatura ambiente. Conclui-se que: a) a emerg?ncia em pl?ntulas de pequizeiro ? influenciada tanto por fatores gen?ticos como ambientais; b) a frequ?ncia de emerg?ncia em pl?ntulas de pequizeiro ? altamente influenciada pela planta matriz da qual foram colhidas; c) O efeito de popula??es (proced?ncias) na emerg?ncia em pl?ntulas de pequizeiro pode ser decorrente do pequeno tamanho dessas popula??es, confundindo-se com o efeito de matrizes; d) O tratamento de sementes de pequizeiro com ?cido giber?lico pode n?o ser garantia de maior emerg?ncia; e) O tempo de armazenamento de sementes de pequizeiro influencia consideravelmente a taxa de emerg?ncia. === Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2009. === ABSTRACT Pequi (Caryocar brasiliense Camb., caryocaraceae) is a widely distributed but endangered Brazilian Cerrado tree specie and its fruits are very appreciated by populations living in this biome. Observations show that temperature fluctuations, a common phenomenon observed among different altitudes, seems to have a strong influence on pequi seeds emergency. Genetic factors appears also to play an important role on this issue. These were the main focus on this work. Seeds from many progenies from three pequi populations (S?o Gon?alo do Rio Preto; Curvelo; and Serro, all of them in Minas Gerais State), strongly distanced from each other, were collected. The 3997 seeds collected in January of 2005 and 2007 years (Trial 1) and the 7035 ones collected in January of 2007 and 2008 years were sown proportionally in Diamantina, MG (a high altitude environment - roughly 1400m) and Curvelo, MG (a low altitude environment ? roughly 650m). The data were collected and organized in contingence tables. The hypothesis for population, progeny (tree), gibberellic acid (GA3), seed age (date of collection) and altitude (temperature) effects were tested by qui-square test for independence. For the trials carried out in Curvelo (high average temperature) in 2007 year, all tested effects were significant (P<0,1%), except populations (P=6,9%) and GA3 (P=6,1%), the last one reducing instead of, as expected, increasing the emergency rate. In the trials carried out in Diamantina (low average temperature) in 2007 year, the probabilities for qui-square tests were all over 10% except seed age (P=5,6%) and progenies (P=9,7%). In 2008 year all effects were significant (P<5%) for both locations. The temperature effects were also significant (P<5%) for the two years, however, against the expectations, in 2008 year, Curvelo (high average temperature) showed a lower emergency rate than Diamantina. The hypothesis to explain it was that the seed plot position was put directly on ground in Diamantina in this year, contrasting with the lifted ones in both locations in 2007 year and in Curvelo in 2008 year. This hypothesis was tested by comparing seed plots lifted with those sow directly on ground in both locations. The results showed that the emergency rate was significantly lower in the seed plots lifted in both Diamantina and Curvelo locations compared to those put directly on ground. May be the night and day temperature fluctuations affect more intensely the lifted seed plot. The main conclusions were: a) pequi seeds emergency are influenced by both genetic and environmental factors; b) it is highly influenced by their original progeny tree; c) progeny tree can also be the main factor responsible for population effects when the population sample is small; d) gibberellic acid is not a guarantee for better emergency in pequi seeds; e) the storage time has a considerable influence on their emergency rate; f) strong day and night temperature fluctuations can reduce the emergency rate in pequi seeds.