ABSTRACT
RESUMO: O alho é uma das hortaliças mais importantes no mercado brasileiro e mundial. No Piauí, mais especificamente na microrregião de Picos, o alho semi-nobre foi cultivado em larga escala e supria a demanda de vários municípios do estado. Devido à entrada do alho nobre no mercado brasileiro, houve redução na produção de alho semi-nobre que pode ter levado à perda de diversidade genética. O objetivo deste trabalho foi estudar a diversidade genética em doze variedades de alho, sendo quatro de origem piauiense e oito da Coleção de Germoplasma de Alho da Escola Superior de Agricultura "Luiz de Queiroz" - Universidade de São Paulo (ESALQ/USP). Para isso, caracterizou-se o germoplasma com base nos descritores propostos pelo International Plant Genetic Resources Institute (IPGRI), atualmente Bioversity International, e realizou-se a genotipagem das variedades a partir de oito locos SSR. Os resultados obtidos com a análise morfológica corroboraram as análises moleculares, evidenciando complementaridade dessas dimensões de análise no estudo da diversidade genética em alho. Assim, conclui-se que existe divergência genética entre as variedades de alho estudadas em função da procedência do germoplasma e sugere-se que o material oriundo da ESALQ/USP trata-se de um germoplasma distinto do cultivado no Piauí. A divergência genética existente entre as variedades de alho no Piauí indica a possibilidade de seleção de genótipos superiores que aumentem a competitividade do alho piauiense frente ao alho importado.
ABSTRACT: Garlic is one of the most important crops in Brazil and in the world. In Piauí State, specifically in micro region of Picos, semi-noble garlic was once grown on a large scale and supplied the demand of various municipalities in the state. After the noble garlic was introduced to the Brazilian market, the production of semi-noble garlic reduced which may have led to loss of genetic diversity.This study investigated the genetic diversity in twelve varieties of garlic, four originally from Piauí State and eight from the Garlic Germplasm Collection of the College of Agricultura "Luiz de Queiroz" - Universidade de São Paulo (ESALQ / USP). The present study characterized the germplasm based on descriptions proposed by the International Plant Genetic Resources Institute (IPGRI), currently Bioversity International, and conducted the genotyping of varieties from eight SSR loci. The agronomic characters and microsatellite genotyping were efficient to estimate genetic diversity among the garlic varieties. The results obtained with the morphological analysis corroborated the molecular analyses, demonstrating complementarity of these analyses dimensions in the study of genetic diversity in garlic. Thus, we concluded that genetic diversity exists among the varieties of garlic studied in terms of the germplasm origin and suggests that the material from the ESALQ / USP is a germplasm distinct from that grown in Piauí State. The genetic divergence among varieties of garlic in Piauí State indicates the possibility of selecting superior genotypes that increase the competitiveness of garlic from Piauí State against imported garlic.
ABSTRACT
In this study, simple sequence repeats (SSR) loci and pedigree data were used to investigate the genetic relationship in a group of 168 Brazilian soybean cultivars. Eighteen SSR loci produced an average of 5.06 alleles and a mean gene diversity of 0.58 for the cultivars studied. Genetic distance (GD) was determined using the modified Roger's Wright distance, and a final dendrogram was in agreement with the cultivar pedigree. A distance matrix based on the coefficient of parentage scores was also generated for the cultivars, which ranged from 0 to 1, with a mean of 0.18, whereas SSR-based genetic similarity (1- GD) ranged from 0.01 to 0.90, with a mean of 0.25. Mantel's Z test showed that the similarity matrices generated from both the data sets were low, but significantly correlated (r = 0.31, p<0.001). The results showed that SSR data and pedigree analyses could help to quantify more accurately the degree of relationship among the soybean cultivars.
Locos microssatélites e dados de genealogia foram utilizados para avaliar a diversidade genética de um grupo de 168 cultivares brasileiras de soja. Os dezoito locos utilizados apresentaram em média 5,06 alelos por loco e coeficiente de diversidade genética médio de 0,58. O dendrograma final resultante da matriz de distância genética de Roger modificado por Wright, apresentou boa concordância com a ancestralidade dos grupos formados. Também foi estimado os coeficientes de parentesco entre as cultivares, sendo observada variação de 0 a 1 com média de 0,18, enquanto que as similaridades para os locos microssatélites (1- GD) variou de 0,01 a 0,90 com média de 0,25. A correlação entre as duas matrizes obtidas determinada pelo teste Z de Mantel apresentou valor baixo, 0,31, mas significativo (p<0,001). Os resultados obtidos sugerem que os locos microssatélites aliados às informações de genealogia proporcionam melhor análise da diversidade genética de cultivares de soja.
ABSTRACT
Soybean genotypes resistant to stink bugs are derived from complex breeding processes obtained through indirect selection. The aim of the present work was to estimate genetic parameters for guiding selection strategies towards resistant genotypes, based on those traits associated with responses to pod-attacking stink bugs, such as the grain filling period (GFP), leaf retention (LR), percentage index of pod damage (PIPD) and percentage of spotted seeds (PSS). We assessed the parental lines IAC-100 (resistant) and FT-Estrela (susceptible), the progenies F2 and F4, 30 progenies F2:3, 30 progenies BC1F2:3 and 30 progenies BC2F2:3, besides the cultivars BRS Celeste and MGBR-46 (Conquista). Three field experiments, using randomized complete block design with three replications, were installed in Goiânia-GO, in the 2002/03 season. Each experiment consisted of 36 treatments (6 common and 30 regular). Heritability estimates were: 74.6 and 36.1 (GFP); 51.9 and 19.9 (LR); 49.6 and 49.6 (PIPD) and 55.8 and 20.3 (PSS), in both the broad and narrow senses, respectively. Based on these results, we concluded that the best strategy for obtaining stink bug-resistant genotypes consists of selecting the PIPD trait in early generations (F3 or F4), followed by selection for the GFP, LR and PSS traits in generations with higher endogamy levels.