VARIA˙'ES GEN…TICAS NA QUALIDADE DO SISTEMA RADICULAR DE MUDAS DE CANDEIA (Eremanthus erythropappus (DC.) MacLeish) 1

RESUMO ñ Com o objetivo de estimar os par‚metros genØticos relativos ‡s qualidades do sistema radicular de candeia, foram utilizadas mudas provenientes de 24 progŒnies de polinizaÁªo livre do Parque Estadual Quedas do Rio Bonito em Lavras, MG. Dois meses apÛs a germinaÁªo, as imagens das raÌzes de nove mudas de cada progŒnie, distribuÌdas em trŒs classes de tamanho (grande, maiores mudas dentro de cada progŒnie, mØdio, mudas mØdias dentro da progŒnie e pequeno, mudas em torno de 5 cm), foram obtidas por scanner Ûptico. Posteriormente, as mesmas raÌzes foram coradas com corante azul de astra 0,1%, durante 15 min, e novamente analisadas. As leituras indicaram diferenÁas significativas entre material nªo-corado e corado, enfatizando o seu uso. Na anÆlise de vari‚ncia, houve diferenÁas significativas entre as progŒnies e entre os tamanhos analisados quanto aos caracteres de raÌzes: comprimento total, Ærea da superfÌcie, di‚metro mØdio e nœmero de raÌzes finas. Os ganhos genØticos esperados com a seleÁªo evidenciaram que esses caracteres devem ser estudados nas mudas grandes, pois apresentam os maiores valores esperados. ABSTRACT ñSeedlings derived from 24 open-pollinated progenies from Quedas do Rio Bonito State Park, Lavras, MG, were used to estimate the genetic parameters concerning the quality of candeia root system. Two months after germination, optical scanning images of new seedling roots were obtained for each progeny, distributed into three size classes (large, medium and small). These roots were stained with 0.1% astra blue for 15 min and then analyzed. The results showed significant differences between stained and non-stained root samples indicating the need for root staining before the analysis. The analysis of variance also showed significant differences among progenies and size classes, which were analyzed considering the following traits: total root length, root surface area, mean diameter and the number of fine roots. The expected genetic gain with selection showed that these traits must be studied in grown seedlings as they showed the largest expected gains.