Walter José Siqueira

PERFORMANCE OF GINGER GRASS (Lippia alba) FOR TRAITS RELATED TO THE PRODUCTION OF ESSENTIAL OIL

Lippia alba (Verbenaceae) is a shrub whose essential oil has important biological, pharmacological, and aromatizing properties. To reach the sustained cultivation of new species with economic potential, the present study aimed to evaluate L. alba performance for fresh leaf matter (FM), leaf dry matter (DM), virus symptoms (VS - Cucumber mosaic virus, CMV), oil yield (OY), and oil chemical composition (OC), and to evaluate DM stability and adaptability. Ten genotypes of four chemical groups (chemotypes) were evaluated in six experiments designed as randomized blocks with two plants per plot, over the whole State of Sao Paulo, Brazil. A 2.0 x 0.4 x 1.6 m spacing was used in Monte Alegre do Sul and Pindorama, while a 1.0 x 0.4 x 0.6 m spacing was used in Campinas, where four experiments were established under different irrigation and fertilization conditions. The genotype effect was significant (p < 0.05) for all traits evaluated, with high leaf productivity of IAC-16 (citral chemotype), best OY means in the linalool and limonene/carvone chemotypes, and susceptibility of the latter chemotype to CMV. The genotype performance oscillations in the six environments were significant for FM and DM, and despite their significance for phytochemical traits (OY and OC), they were of low magnitude. No qualitative variation was detected for OC. The IAC-2 (linalool) and IAC-13 (limonene/carvone) genotypes showed high stability and wide adaptability, and are recommended to establish initial cultivations of this species. This research also indicated genetic sources to start Lippia alba genetic breeding programs.

Caracterização isoenzimática e morfológica de clones e introduções de alho

Em virtude do grande numero de denominacoes locais para clones de alho, nem sempre correspondentes a materiais distintos, conduziu-se o presente estudo objetivando a caracterizacao e classificacao de 72 clones e introducoes de alho (Allium sativum L.), e um clone de alho-rei (A. ampeloprasum L.). Isso foi feito analisando as isoenzimas alcooldesidrogenase (ADH), esterase (EST), peroxidase (PRX) e fosfoglucoisomerase (PGI) atraves da tecnica de eletroforese horizontal em gel de amido hidrolisado de batata. Verificou-se que os clones nacionais e introduzidos se enquadram nos grupos aqui denominados DIKA ou CJLB, respectivamente para os padroes de ADH, EST, PRX e PGI. Entretanto, os padroes CILB, CJKB e CIKB foram observados em alguns clones estrangeiros, sugerindo sua maior variabilidade em relacao aos nacionais. O alho-rei apresentou padroes diferentes dos encontrados na especie A. sativum L. A associacao dos resultados da tecnica de eletroforese de isoenzinas com a caracterizacao morfologica da parte aerea, bulbos, bulbilhos, coloracao externa dos bulbos e bulbilhos e ciclo cultural, permitiu a classificacao dos clones nacionais de alho em 19 grupos distintos.

DNA tagging of blast resistant gene(s) in three Brazilian rice cultivars

Rice blast is the most important fungal disease of rice and is caused by Pyricularia oryzae Sacc. (Telomorph Magnoporthe grisea Barr.). Seven randomly amplified polymorphic DNA (RAPD) markers OPA5, OPG17, OPG18, OPG19, OPF9, OPF17 and OPF19 showed very clear polymorphism in resistant cultivar lines which differed from susceptible lines. By comparing different susceptible lines, nine DNA amplifications of seven primers (OPA51000, OPA51200, OPG17700, OPG18850, OPG19500, OPG19600, OPF9600, OPF171200 and OPF19600) were identified as dominant markers for the blast resistant gene in resistant cultivar lines. These loci facilitate the indirect scoring of blast resistant and blast susceptible genotypes. The codomine RAPDs markers will facilitate marker-assisted selection of the blast resistant gene in two blast resistant genotypes of rice (Labelle and Line 11) and will be useful in rice breeding programs.

Isoenzimas na identificação precoce de híbridos e clones nucelares no melhoramento de citros

Um dos problemas relacionados ao melhoramento de citros e a poliembrionia e a consequente dificuldade, apos cruzamentos controlados, de distinguir clones nucelares dos hibridos. Estudou-se um metodo para eletroforese de isoenzimas em gel de amido para doze sistemas isoenzimicos, desenvolvendo-se procedimento apropriado para a resolucao simultânea dos sistemas fosfatase acida, peroxidase anodica e catodica, glutamato oxaloacetico transaminase, fosfoglucoisomerase, fosfoglucomutase e enzima malica. Caracterizaram-se por esses sistemas 31 clones de citros com possivel interesse para o programa de melhoramento do IAC. Estao envolvidos 7 locos e 25 alelos, permitindo uma identificacao precoce de hibridos antes do plantio no campo para avaliacoes agronomicas. Implicacoes desses estudos basicos no melhoramento e na determinacao da taxa de seedlings nucelares de porta-enxertos comerciais sao discutidas.

Desempenho agronômico de híbridos F1 de tomate de mesa

The study aims to obtain and select F1 resistant hybrids of tomato for fresh market and evaluate their agronomic attributes in field conditions. The work was carried out at Nunhems Experimental Station, located in Paulinia, Sao Paulo State, Brazil, from February to June 2008. The experimental design was completely randomized blocks with 36 treatments, four replications and ten plants per plot. Based on the grouping of means by Scott-Knott test, the performance of hybrids for seven agronomic traits showed great variability among genotypes for fruit length and width with four groups of means. There was good variability for yield per plant, and plant height with three groups of means for each character. The traits fruit number per plant, cluster number per plant, and distance between the first cluster and the ground showed little divergence with two grouping means. HE-38 and HE-14 outperformed the standard Aplauso for fruit yield per plant showing positive heterotic effects.

Evaluation of the chemical composition and toxic constituent in physic nut plants from different localities.

Summary The aim of this work was to evaluate the chemical composition and the presence of the toxic constituent, phorbol esters, in samples of physic nut ( Jatropha curcas). Samples of physic nut seeds produced in different regions of Brazil were analyzed. The physical chemical composition of the seeds was determined using official AOCS methodology (FIRESTONE, 2006) for the protein, moisture, ash, crude fiber and oil contents. The characteristics of the oil with respect to the fatty acid composition were determined after preparation of methyl esters and injection into a gas chromatograph. The saponification and iodine indexes and average molecular weight of the fatty acids were calculated based on the fatty acid composition. The phorbol ester content was determined using high performance liquid chromatography. The samples showed average moisture contents of 7.46 and 16.11% of protein. The oil yield ranged from 11.29 to 39.70% with an average of 31.51%, and the predominant fatty acids were oleic and linoleic. The variation in fatty acid content did not influence the saponification index, which is related to the average molecular weight of the fatty acids, but did affect the iodine index, which is related to the degree of unsaturation of the fatty acids and can consequently affect the oxidative stability of the oil. The phorbol ester content, the main toxic component, ranged from 1.41 to 8.97 mg.g

A tristeza dos citros e suas implicações no melhoramento genético de porta-enxertos

Brazil is the world leading citrus producer and historically, tristeza is the most serious disease in economic importance. Tristeza is caused by a single strand RNA closterovirus, Citrus Tristeza Virus (CTV), is disseminated in almost all citrus regions of the world. It is transmitted by grafting and by several species of aphids mainly Toxoptera citricida. There are several virus strains, causing variable symptoms in the majority of species and related genera of Citrus. Cross-protection by mild virus strains is an efficient technique for protecting very sensitive scions in Brazil and elsewhere. Methods for detecting and characterizing virus strains are classically based on the reaction symptoms of specific varieties and clones. However, development of serological and molecular methods have allowed progress in the characterization and in monitoring the spread of the disease. Plants may be infected with more than one strain that can undergo genetic recombination, show differential transmissibility by the vector aphids, have composition of the strain complex altered by drastic pruning, temperature, and also segregate among budwoods, or by sub-culture in different clones. Smaller defective RNAs are often associated with normal CTV particles, some correlated with symptoms of seedling yellows. Efficient control is achieved by favorable combinations of scions and rootstocks. They react in predictable interactions dependent on both, the capability to multiply the viruses and to tolerate their presence in phloem tissues. These peculiarities have important implications on practical cultivation and on the genetic improvement of scions and rootstocks. This review discuss also the reaction of grafted and non-grafted plants, and highlights problems, basic concepts and relevant implications for citrus rootstock improvement.

Breeding and Biotechnology of Jatropha curcas

The growing demand for renewable energy sources will increase the demand for oilseeds in Brazil and worldwide. This demand will only be supplied if plant varieties with exceptional agronomic and chemical traits are developed. This process can be accelerated by application of biotechnology and molecular biology techniques, as we have done in the case of Jatropha curcas, a perennial oilseed. We have used two strategies: (1) Exploitation of pre-existing variability in the germplasm of J. curcas evaluated through morphological, molecular and chemical markers (such as fatty acid and phorbol esters content). We also investigated self-fertilization with selected genotypes to analyze the effects of inbreeding, particularly with regard to the production of non-toxic, smaller, male-sterile and gynoic plants; and (2) Increase the genetic variability through interspecific hybridization and biotechnology. Despite the post-zygotic incompatibility encountered in most interspecific crosses, the use of artificial hybridization coupled with tissue culture techniques, such as in vitro embryo rescue and subsequent multiplication via somatic embryogenesis has yielded unprecedented results in the form of rare hybrids between J. curcas and other species of this genus. So far, we have obtained more than 80 F1 hybrids and 140 BC1 × F1 backcross progenies. Evaluation of these hybrids and the continuation of this line of research will greatly expand the germplasm bank of Instituto Agronomico de Capinas (IAC) and should contribute significantly to rapid production and release of new improved cultivars. In addition to their application in assessing genetic variability, molecular markers were useful to confirm F1 hybrids and BC1 generations by excluding the possibility of apomixis and to select suitable plants for genetic breeding.

Isolation and characteristics of eight novel polymorphic microsatellite loci in Lippia alba (Verbenaceae)

PREMISE OF THE STUDY A set of eight microsatellite (simple sequence repeat [SSR]) markers for Lippia alba, an important medicinal and cosmetic plant, was developed to aid studies of genetic diversity and to define efficient strategies for breeding programs. METHODS AND RESULTS Using a (CT)(8)- and (GT)(8)-enriched library, a total of 11 SSR loci were developed and optimized in L. alba. Of the 11 loci, eight were found to be polymorphic after screening 61 accessions from two populations. The parameters used to characterize loci were expected heterozygosity (H(e)) and number of alleles. A total of 44 alleles were identified, with an average of 5.5 alleles per loci, which were moderately to highly informative according to H(e). CONCLUSIONS These new SSR markers have potential for informing genetic diversity, allele mining, and mapping studies and will be used to generate information for breeding programs of L. alba.

Caffeine inheritance in interspecific hybrids of Coffea arabica x Coffea canephora (Gentianales, Rubiaceae)

Caffeine inheritance was investigated in F2 and BC1F1 generations between Coffea arabica var. Bourbon Vermelho (BV) and Coffea canephora var. Robusta 4x (R4x). The caffeine content of seeds and leaves was determined during 2004 and 2005. Microsatellite loci-markers were used to deduce the meiotic pattern of chromosome pairing of tetraploid interspecific hybrids. Genetic analysis indicated that caffeine content in seeds was quantitatively inherited and controlled by genes with additive effects. The estimates of broad-sense heritability of caffeine content in seeds were high for both generations. In coffee leaves, the caffeine content (BSH) from the same populations showed transgressive segregants with enhanced levels and high BSH. Segregation of loci-markers in BC1F1 populations showed that the ratios of the gametes genotype did not differ significantly from those expected assuming random associations and tetrasomic inheritance. The results confirm the existence of distinct mechanisms controlling the caffeine content in seeds and leaves, the gene exchange between the C. arabica BV and C. canephora R4x genomes and favorable conditions for improving caffeine content in this coffee population.