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.

SUMMARYLand use and soil management may affect both labile and humified soil organic matter (SOM) RESUMO O uso e manejo do solo podem afetar as frações lábeis e humificadas da matéria orgânica (MO), mas a magnitude destas alterações é pouco conhecida em ambientes subtropicais. Este estudo avaliou os efeitos de quatro sistemas de uso e manejo do solo (mata, campo nativo, preparo convencional e plantio direto na sucessão trigo/soja) sobre (i) o estoque de carbono orgânico total (COT) (0-250mm), e nos (ii) estoques de carbono (C) em frações lábeis (grosseira, leve) e humificadas (associada aos minerais, substâncias húmicas) da MO na camada superficial (0-25mm) de um Latossolo bruno, no

The aryloxyphenoxypropionate herbicides (APPs) are graminicides with excellent control of many grass weeds species, including weedy rice (Oryza sativa L.). These herbicides block the fatty acid biosynthesis by inhibiting the enzyme acetyl-CoA carboxylase (ACCase), resulting in the death of susceptible plants. Inducing mutation with gamma rays to rice seeds, two lines resistant to APPs herbicides were developed. Plant dose-response assays confirmed the resistance to the APPS herbicides quizalofop-p-ethyl and haloxyfop-p-methyl. The carboxyltransferase domain fragments of ACCase from the resistant biotype and susceptible control were sequenced and compared. A point mutation was detected in the amino acid position 2,027 (Rice Genome Annotation Project: Os05g22940.1). Results indicated that resistance to APPs is a consequence of an altered ACCase enzyme that confers resistance. The use of APPs herbicide-resistant rice lines represents an innovative and promising alternative for weedy rice control in paddy rice systems.

Abstract"Specialty rices" is a common name for varieties that present uncommon grains with distinctive features as pericarp color, grain shape and size or aroma. Most of these rices are related to cultural traditions and ceremonies, but some have higher nutritionally value than white rice. Considering that today people are searching for foods that could help to improve and maintain health, specialty rices would also be considered in some way as functional food. As a specific market, the economic values of these grains are also higher than those of white rice. So, the new red rice variety SCS119 Rubi and the new black rice variety SCS120 Onix were developed in order to attend the specific and economically important specialty rices market, and should be consumed as a whole rice grain. Experimental tests performed with these varieties showed that they could be recommended to all rice-producing regions of Santa Catarina State, Brazil.