Variability of five arboreous species of the Central Brazil cerrado region for germination and emergency measurements
Basic studies of seed germination and seedling emergence assume an important rolewithin scientific researches due to the devastation and fragmentation of the nativevegetation of the Cerrado. Thus, in the present study the processes of seed germinationand seedling emergency were evaluated using the linear correlations among themeasurements calculated for five Cerrado species. The individual contribution for thevariability of the studied species and the contribution of each species in relation to thestudied group were also quantified. For this purpose, hierarchical lineal models wereused to determine the genetic parameters among individuals within the species. Thediaspores were collected in the 2004/2005 crops, in a fragmented area of the Araguaririver valley, MG. The experiments were carried out using newly-collected diaspores,being conducted in a germination chamber for germination and in a greenhouse coveredwith light reducing net for seedling emergency. The data collection was carried outevery 24 hours, taking into account the protrusion of the embryo for the experiments setup in the laboratory and the emergence of any part of seedling above the substratum forexperiments kept in greenhouse. The variability registered among the individuals of thestudied species generated statistical differences in all aspects of the germination andemergency processes, indicating that the decision to mix the diaspores or not for theformation of the lots should be made after results of previous tests. High mean valueswere registered for germinability (G) and emergency percentage (E) for the majority ofindividuals studied, indicating the good physiological quality of the diaspores producedin the 2004-2005 crop. The seed germination and seedling emergence of Anadenantheracolubrina and Chorisia speciosa and the seedling emergence of Myracrodruonurundeuva were faster and synchronized, while those of Cedrela fissilis and Lithraeamolleoides were slower, asynchronous and spread over time, indicating the presence ofrelative dormancy. These germination and emergence patterns were confirmed bymeans of positive linear correlations between E and Z (synchrony) and negativebetween E and U (uncertainty) for the synchronous events; negative correlationsbetween E and Z and positive and E and U for the asynchronous. For C. speciosa thesynchrony of germination was also expressed by the positive association between G andv (mean germination rate). The partition of the variability allowed one to verify that thegermination process and seedling emergence present a pattern behavior intrinsic to eachspecies, with more than 60% of the total variability attributed to the species. Above 0.80of the heritability was registered for most of the characteristics evaluated, indicating thatthe largest proportion of the total variability is of genetic nature. High geneticvariability, expressed by the CVg and detected for time, rate, and synchronymeasurements was registered between the L. molleoides and C. fissilis individuals. Themagnitude of the CVg values showed that genetic variation exists in the studied speciesin relation to the germination and emergency processes and then they should beincluded in conservation projects.
Advisor:Denise Garcia de Santana; Fátima Conceição Marquez Pinã Rodrigues; Rogério de Melo Costa Pinto; Marli Aparecida Ranal
School:Universidade Federal de Uberlândia
Source Type:Master's Thesis
Keywords:Aninhamento Emergency measurements Germination Heritability Nested Tropical trees
Date of Publication:10/25/2007