A r t i c l e s Theobroma cacao L. is a diploid tree fruit species (2n = 2x = 20 (ref. 1)) endemic to the South American rainforests. Cocoa was domesticated approximately 3,000 years ago 2 in Central America 3. The Criollo cocoa variety, having a nearly unique and homozygous genotype, was among the first to be cultivated 4. Criollo is now one of the two cocoa varieties providing fine flavor chocolate. However, due to its poor agronomic performance and disease susceptibility, more vigorous hybrids created with foreign (Forastero) genotypes have been introduced. These hybrids, named Trinitario, are now widely cultivated 5. Here we report the sequence of a Belizean Criollo plant 6. Consumers have shown an increased interest for high-quality chocolate, and for dark chocolate, containing a higher percentage of cocoa 7. Fine-cocoa production is nevertheless estimated to be less than 5% of the world cocoa production due to the low productivity and disease susceptibility of the traditional fine-flavor cocoa varieties. Therefore, breeding of improved Criollo varieties is important for sustainable production of fine-flavor cocoa. 3.7 million tons of cocoa are produced annually (see URLs). However, fungal, oomycete and viral diseases, as well as insect pests, are responsible for an estimated 30% of harvest losses (see URLs). Like many other tropical crops, knowledge of T. cacao genetics and genomics is limited. To accelerate progress in cocoa breeding and the understanding of its biochemistry, we sequenced and analyzed the genome

Red seaweeds are key components of coastal ecosystems and are economically important as food and as a source of gelling agents, but their genes and genomes have received little attention. Here we report the sequencing of the 105-Mbp genome of the florideophyte Chondrus crispus (Irish moss) and the annotation of the 9,606 genes. The genome features an unusual structure characterized by gene-dense regions surrounded by repeat-rich regions dominated by transposable elements. Despite its fairly large size, this genome shows features typical of compact genomes, e.g., on average only 0.3 introns per gene, short introns, low median distance between genes, small gene families, and no indication of large-scale genome duplication. The genome also gives insights into the metabolism of marine red algae and adaptations to the marine environment, including genes related to halogen metabolism, oxylipins, and multicellularity (microRNA processing and transcription factors). Particularly interesting are features related to carbohydrate metabolism, which include a minimalistic gene set for starch biosynthesis, the presence of cellulose synthases acquired before the primary endosymbiosis showing the polyphyly of cellulose synthesis in Archaeplastida, and cellulases absent in terrestrial plants as well as the occurrence of a mannosylglycerate synthase potentially originating from a marine bacterium. To explain the observations on genome structure and gene content, we propose an evolutionary scenario involving an ancestral red alga that was driven by early ecological forces to lose genes, introns, and intergenetic DNA; this loss was followed by an expansion of genome size as a consequence of activity of transposable elements.T he red algae, together with the glaucophytes and the Chloroplastida, are members of the Archaeplastida, the phylogenetic group formed during the primary endosymbiosis event that gave rise to the first photosynthetic eukaryote. Red algal genomes, both plastid and nuclear, also contributed, via secondary endosymbiosis, to several other eukaryotic lineages, including

Genetic relationship can be a useful predictor of the relative performance of hybrid combinations for a hybrid breeding program resulting in reduced time and cost of hybrid testing. Genetic relationships of 112 wheat (Triticum aestivum L. em. Thell.) lines were estimated using 41 DNA clones hybridizing to 273 DNA fragments and by calculating coefficient of parentage (COP). Heterosis was estimated for 722 hybrids grown in multiple locations, with 189 being tested in more than 1 year. The average RFLP (restriction fragment length polymorphism) based genetic distance index (DI) was 0.35. Midparent heterosis for grain yield ranged from −20 to 57% and high-parent heterosis from −22 to 47%. The correlation between RFLP-based estimates of genetic distance and COP was nonsignificant (−0.33). Coefficient of parentage was significantly correlated with heterosis for all traits in 1991 but not in other years. Genetic distance based on RFLPs scored in this study was not correlated with heterosis in any of the years tested. Further refinement of gene pools and new prediction methods will be required to facilitate the exploitation of genetic variability for hybrid wheat improvement. Key words : wheat, heterosis, genetic distance.

The characterization of genetic variability and an estimate of the genetic relationship among varieties are essential to any breeding program, because artificial crosses among less similar parents allow a larger segregation and the combination of different favorable alleles. Genetic variability can be evaluated in different ways, including the Coefficient of Parentage (COP), which estimates the probability of two alleles in two different individuals being identical by descent. In this study, we evaluated the degree of genetic relationship among 53 wheat genotypes, and identified the ancestor genotypes which contributed the most to the current wheat germplasm, as a prediction of the width of the genetic base of this cereal. The results revealed a mean COP of 0.07 and the formation of 22 similarity groups. The ancestor genotypes Ciano 67 and Mentana were those which contributed the most to the current wheat germplasm. According to the COP analyses, the genetic base of wheat rests on a small number of ancestral genotypes.

Eighteen barley genotypes used in Brazilian malting barley breeding programs were characterized in relation to (1-3, 1-4)-␤-glucanase activity in green and kilned malt. They were tested to determine the loss of enzyme activity during kilning in the malting process and the environmental effects on enzyme activity were measured. The genotypes analyzed showed great variation regarding the enzyme activity in both kinds of malt, in a range from 531.94 to 934.31 U /kg in green malt, and from 187.02 to 518.40 U /kg in dry malt. The mean enzyme activity loss during kilning was close to 60%, very similar to the results obtained in other studies. The loss among genotypes varied from 8.04% to 71.54%. The enzyme activity varied significantly under the different environments tested, showing existence of environmental effects on the genotypes analyzed. Embrapa 127 was the genotype that exhibited the highest enzyme activity in finished malt although it had shown a low activity in green malt, reflecting a negligible loss of activity during kilning. The data indicate promising results to malting barley breeding due to the wide variability exhibited by genotypes as to enzyme activity and levels of isoenzyme with high thermostability.

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RESUMO -O desenvolvimento de genótipos de milho com adaptação à região sul do Brasil requer a identificação devariabilidade genética, assim sendo, o objetivo deste trabalho foi caracterizar variedades crioulas de milho coletadas no estado de Santa Catarina e verificar sua possível contribuição para programas de melhoramento genético. No total foram avaliados 42 genótipos de milho para 33 caracteres fenotípicos e 16 microsatélites. A análise de variância sugeriu a presença de variabilidade genética em 17 dos 24 caracteres quantitativos avaliados, indicando que as populações testadas poderiam contribuir efetivamente para o melhoramento genético do milho no sul do Brasil. De maneira geral, as variedades crioulas exibiam grãos dentados ou semi-dentados de coloração amarela, branca ou laranja. A estatura de planta e a inserção da primeira espiga foram elevadas e o comportamento médio de produtividade de grãos das variedades crioulas foi de 2709 kg/ha, sendo baixo na comparação com variedades melhoradas. As populações analisadas não representam contribuição importante em termos de produtividade de grãos, mas podem fornecer alelos para o melhoramento de diversos caracteres agronômicos de importância para a cultura do milho no sul do Brasil. Palavras-chave: Variabilidade genética, Caracteres morfológicos, Marcadores moleculares, Zea mays PRELIMINAR ANALYSIS OF MAIZE LANDRACES GERMPLASM FROM SOUTHERN BRAZILABSTRACT -Genotype development for Southern Brazil requires identification of genetic variability. The objective of this study was to characterize maize landraces collected in Santa Catarina State and to assess its possible contribution to plant breeding programs. A total of 42 maize genotypes was evaluated for 33 phenotypic traits and 16 microsatellites. Analysis of variance suggested the presence of genetic variability in 17 of the 24 quantitative traits evaluated, indicating that the populations tested could effectively contribute for the genetic improvement of maize in southern Brazil. In general, the landraces exhibited dent or semi-dent yellow, white or orange grains. Plant height and first ear insertion were high and the average grain yield was 2709 kg/ha, which is low when compared to improvedvarieties. The different populations may not have important contribution in terms of grain yield, but they may provide alleles for the adjustment of several agronomic traits of corn in southern Brazil. geral, as variedades crioulas exibiam grãos dentados ou semi-dentados de coloração amarela, branca ou laranja. A estatura de planta e a inserção da primeira espiga foram elevadas e o comportamento médio de produtividade de grãos das variedades crioulas foi de 2709 kg/ha, sendo baixo na comparação com variedades melhoradas. As populações analisadas não representam contribuição importante em termos de produtividade de grãos, mas podem fornecer alelos para o melhoramento de diversos caracteres agronômicos de importância para a cultura do milho no sul do Brasil.