Understanding the genetic structure of the population of Alternaria solani (AS) is an important component of epidemiological studies of early blight, a severe disease that affects potato (Po) and tomato (To) worldwide. Up to 150 isolates obtained from both hosts were analysed with RAPD and AFLP markers to estimate the amount and distribution of genetic variability of AS in Brazil. Using RAPD, gene diversity (h = 0.20) and scaled indices of diversity of Shannon (H¢ = 0.66) and Stoddart and TaylorÕs (G = 0.31) for the Po population were higher than those of the To (h = 0.07, H¢ = 0.34, G = 0.17). For AFLP, the statistics for the Po (h = 0.17, H¢ = 0.86, G = 0.49) and To (h = 0.17, H¢ = 0.85, G = 0.36) populations were similar. For each RAPD and AFLP locus, the allele frequency for the overall population ranged from 0.006 to 0.988, and 0.007 to 0.993, respectively. Genetic differentiation was high (G ST = 0.41 and h = 0.59) and moderately high (G ST = 0.23 and h = 0.37) when estimated with RAPD and AFLP, respectively. Based on cluster analyses, there was strong evidence of association of pathogen haplotypes with host species. The null hypothesis of random association of alleles was rejected in the analysis of both RAPD (I A = 13.1, P < 0.001) and AFLP (I A = 2.2, P < 0.001) markers. The average number of migrants was estimated to be around one and two individuals per generation, using RAPD and AFLP, respectively. There was no correlation between genetic distance and geographical origin of AS haplotypes for RAPD (r = )0.07, P = 0.84) and AFLP (r = )0.03, P = 0.70). The AS population is clonal with high genetic variability, and there is genetic differentiation between the populations that affect To and Po.

quem me incentivou e permitiu que me ausentasse para participar das aulas do mestrado. Ao professor, José Magno Queiróz Luz, que me apoiou e me orientou. À professora, Denise Garcia Santana, que deu grande suporte em todos os quesitos estatísticos. Aos meus queridos irmãos, amigos e familiares que sempre estiveram juntos comigo na realização deste sonho. Muito Obrigado! Um homem deve ouvir todas as vozes que lhe rodeia, em especial, a voz de Deus. Mas, deve seguir somente o caminho que seu próprio coração lhe indicar. Pare e pense, se desvencilhe de tudo, ore, decida e siga. Antônio Campos BIOGRAFIA Nascido aos 28 de junho de 1982 na cidade de Aiuruoca-MG, onde viveu e completou, aos 14 anos, o ensino fundamental na Escola Estadual Conselheiro Fidelis. Concluiu o ensino médio no Instituto Presbiteriano Gammon, na cidade de Lavras, no ano de 1999. Graduado em Agronomia pela Universidade Federal de Viçosa em 2006, através da qual participou do programa de estágio Comunication Agriculture Program, nos Estados Unidos, por um ano. Iniciou sua carreira como Assistente de melhorista na empresa Sakata Seeds Sudamerica. Atualmente, trabalha na Empresa Bayer Vegetable Seeds como melhorista.

Sugarcane is cultivated in almost all Brazilian agricultural regions, Brazil being the world's largest producer, which requires breeding programs to create more productive and efficient varieties adapted to each region. In sugarcane breeding programs there is a need, under certain circumstances, to multiply the selected material rapidly. In this scenario, micropropagation appears as an alternative to the conventional process of vegetative propagation through stalks. The objective of this review was to describe the scenario on micropropagation research in sugarcane, such as meristem culture, sugarcane calli, somatic embryogenesis, in vitro germplasm conservation and cryopreservation. It has been observed in the literature that there is a wide spectrum of use for the numerous and well established protocols for the in vitro manipulation of sugarcane morphogenesis. The prospect of producing new features via induction of somaclonal variation and in vitro experimentation for pest and disease tolerance has not yet been extensively explored. While benefits of minimal growth are recognized in in vitro germplasm conservation of elite sugarcane cultivars, and all positive potential of this technique and cryopreservation may still 323 Colloquium Agrariae, vol. 13, n. Especial, Jan–Jun, 2017, p. 322-338 ISSN: 1809-8215. DOI: 10.5747/ca.2017.v13.nesp.000237 be expanded. On the other hand, techniques in the mass production of superior and pathogenfree genotypes have already been integrated in many sugarcane breeding programs.