Alexsandro Lara Teixeira

Eficiência da seleção para incremento do teor de óleo do pinhão-manso

The objective of this work was to estimate the genetic parameters of physic nut (Jatropha curcas) grain quality traits and to quantify the genetic progress with selection. Seed oil content, and seed, kernel, and shell weights of 120 plants, randomly selected in a commercial planting, were evaluated at 36 and 48 months. Genetic progress was quantified by the evaluation of direct gains and by the use of selection indexes. The genotype x measurement interaction was significant for all evaluated traits; therefore, there are genotypes with different behavior in the two cropping seasons. The genetic parameters indicated a higher proportion of genotypic variation in the expression of the evaluated traits, and a trend of the genotypes to maintain their genetic superiority over time was observed. The genotype-ideotype selection index resulted in higher genetic gains and promoted a more balanced alteration in the trait means. The direct selection for kernel weight results in genetic gains similar to those obtained with the use of the selection indexes.

Avaliação do teor de cafeína em folhas e grãos de acessos de café arábica

The aim of this study was to identify, within the germplasm bank of the Minas Gerais state, Coffea arabica L. accessions with low levels of caffeine and check the correlation between grain and leaves in seedling stage, making possible the practice of early selection. Seventy-five coffe accessions (cultivars, hybrids and several wild genotypes) were evaluated from the coffee germplasm bank of the Minas Gerais state. In the correlation study, eight cultivars were used on randomized complete block design with three replications. Were evaluated the caffeine levels in the grains and the third and fourth pair of true leaves. Six accessions had caffeine levels in grains smaller than 0.88%. Was also detected a significant correlation between the caffeine levels in the third (0.69) and fourth (0.92) pair of leaves and grains. Genotypes were identified with low levels of caffeine and great yield may be used as parental in breeding programs. It is possible to perform early selection for caffeine content in coffee plants, still in the seedling stage, by evaluating the fourth pair of leaves.

Progresso genético da produtividade de café beneficiado com a seleção de clones de cafeeiro 'Conilon'

A especie Coffea canephora Pierre ex Froehner possui ampla distribuicao geografica, com ocorrencia em regioes tropicais de diversos continentes. Aproximadamente 30% da producao brasileira de cafe e proveniente do cultivo dessa especie, sendo que o Estado de Rondonia se destaca como seu segundo maior produtor. Este trabalho teve como objetivo estimar os parâmetros geneticos com a selecao de clones de C. canephora, da variedade botânica ´Conilon’, visando caracterizar a variabilidade genetica e estimar o progresso genetico da produtividade de cafe beneficiado. A analise de variância da producao de cafe beneficiado evidenciou que a fonte de variacao “clones” foi significativa nas safras avaliadas, de acordo com o teste F a 1% de significância. A predominância do componente genetico na expressao dessa caracteristica, associado a uma boa precisao experimental, indica a possibilidade de obtencao de ganhos com a selecao de plantas. O progresso genetico da producao de cafe beneficiado com o plantio dos clones selecionados foi de 57,85%, que equivale a um aumento na media em quatro anos de 44,75 sacas ha-1, para 70,64 sacas ha-1. Alem do incremento na produtividade de graos, os clones de ciclo intermediario selecionados favorecem a concentracao da colheita e a reducao dos custos operacionais.

Yield, maturation, and beverage quality of arabica coffee progenies under selection in Rondonia state, Brazil

In this paper, we studied coffee bean yield, maturation, and other characteristics of special progenies of Arabica coffee (Coffea arabica L.) grown under high temperatures in a low altitude region in the state of Rondonia, Brazil. We evaluated 29 progenies developed by the Instituto Agronomico de Campinas ? IAC, namely, 24 F2BC2 progenies of Obata (C. arabica with introgressions of C. canephora) x (C. eugenioides 4n x C. arabica), three F3 progenies of Catuai x Glaucia, and two H419 lines. Seven cultivars were used as controls. A randomized block design was used with three replications, spacing of 3.0 × 1.0 m, and ten plants per plot. All the crop seasons showed a significant difference for the hulled coffee yield trait. In combined analysis, significant difference was detected among progenies, among controls, and in the progeny vs control contrast. In the average of the four harvests, hulled coffee yield was 29.30 bags ha-1. The F2 progeny Obata x (Catuai x EUG DP x MN) C.1594 stood out from the others with a mean yield of 47.37 bags ha-1. The cultivars received beverage scores from 40 to 62, ?rioysh? to ?hard? beverage classification, while the progenies had scores from 40 to 80, ?rio? to ?barely soft? beverage classification. In regard to the maturation cycle, eleven progenies were late (April), eleven intermediate (March), and seven early (February). For continuity of advancement of generations, 104 plants were selected, derived from 22 progenies with the best productive performance, late maturation cycle, and good beverage quality.

Seleção precoce para produção de grãos em café arábica pela avaliação de caracteres morfológicos

The objective of this work was to assess the viability of early selection in Arabica coffee using the correlation between morphological traits and grain yield. Two hundred and sixty-nine accessions of Coffea arabica, among cultivars, hybrids, and wild genotypes, from Epamigs coffee germplasm bank, Patrocinio, MG, Brazil, were evaluated. A randomized complete block design was used, with two replicates, at a spacing of 3.5x0.8 m, with ten plants per plot. Morphological traits were evaluated in 2006, 12 months after planting, when plants were still at the juvenile phase. Grain yield data are from the 2008/2009 and 2009/2010 crop seasons. The length of the first plagiotropic stem, at 12 months of age, was highly correlated and showed a high direct effect in a favorable direction toward grain yield, being the main morphological trait responsible for variations in grain yield. The vegetative vigor at 12 months of age was the most important secondary variable in explaining the variations in grain yield. These traits can be used effectively in the early selection for grain yield in Arabica coffee.