Marcelo Geraldo de Morais Silva

Seleção recorrente intrapopulacional no maracujazeiro amarelo: alternativa de capitalização de ganhos genéticos

Objetivou-se, neste trabalho, estimar parâmetros geneticos e correlacoes associadas a caracteristicas agronomicas do maracujazeiro amarelo (Passiflora edulis Sims), predizer o progresso genetico esperado com a selecao direta e baseado em indice de selecao, bem como sugerir uma estrategia de capitalizacao de ganhos geneticos nos ciclos de selecao recorrente. Foram avaliadas 26 progenies de meio-irmaos provenientes da recombinacao de genotipos selecionados do primeiro ciclo de selecao via Delineamento I, as quais representam a populacao melhorada, UENF/MA1. O delineamento estatistico utilizado foi blocos casualizados com duas repeticoes e parcelas constituidas de cinco plantas. Foram avaliadas cinco caracteristicas relacionadas ao fruto, no periodo de fevereiro a julho de 2007, utilizando dados de media de parcelas. As estimativas dos parâmetros geneticos e das correlacoes, bem como a selecao baseada no indice de selecao possibilitaram a identificacao de progenies com desempenhos agronomicos superiores para varios caracteres, simultaneamente. Alem disso, a presente estrategia pode constituir alternativa de capitalizacao de ganhos geneticos na selecao recorrente, aumentando a eficiencia do processo seletivo e potencializando a sua utilizacao em programas de melhoramento de fruteiras, uma vez que permite ganho genetico em duas (geracao e teste de progenies) das tres etapas de selecao recorrente.

Diversidade genética em seleção recorrente de maracujazeiro-amarelo detectada por marcadores microssatélites

The objective of this work was to estimate the genetic variability in two recurrent selection cycles of the yellow passion flower (Passiflora edulis), and to evaluate the impact of selection on the progenies selected via changes in allele frequency, detected by microsatellite markers. Twenty-three microsatellites were used for genotyping 66 full-siblings. Allele frequency, expected (He) and observed (Ho) heterozygosity, polymorphic information content (PIC) and inbreeding coefficient (f) were estimated. Thirty-two alleles were found in these populations, of which only two were lost during selection. The average number of alleles per locus was 2.46 in the first cycle, and 2.30 in the second. The differences in allele frequencies in the two cycles were not significant. The mean He in the first cycle was 0.20 per locus, slightly higher than Ho (0.15). In the second selection cycle, the mean value of Ho was lower than of He, with an average of 0.12. The mean values of f increased in the second selection cycle, from 0.26 to 0.32. Most of the loci showed negative values of f, which suggests high levels of heterozygosity. The mean value of PIC decreased from 0.18 to 0.16 in the second cycle. There were small losses of variability and changes in allele frequencies; however, these variations can be considered normal when selection is practiced.

Alternativas de seleção em população de maracujazeiro-azedo sob seleção recorrente intrapopulacional

In breeding programs, it is common to the assessment of many traits in order to practice selection in several of them simultaneously, in order to obtain uniform genotypes for defferent traits under selection. A viable alternative to this technique is the use of selection indices, using multivariate techniques to associate information about various traits of agronomic interest with the genetic properties of the studied population. The objective of this study was to predict the expected progress with selection by means of different multivariate selection indices. Were planted in October 2007, 140 full-sib progenies of passion fruit in square lattice design with two replications and plots consisting of three plants. We evaluated eleven characters. The non-parametric multivariate indices Mulamba and Mock and index the distance Genotype-ideotype, allowed to predict higher earnings and a balanced way between the characteristics when compared with the parametric indices of Smith and Hazel and Pesek and Baker. Using non-parametric indices was possible to select superior progenies for most traits simultaneously continuing the regional improvement program running.

Biometria aplicada ao melhoramento intrapopulacional do maracujazeiro amarelo

The objective of the study was to estimate genetic parameters associated with eleven agronomic traits of a population of yellow passion fruit under recurrent selection, using 140 full-sibling progenies from the second cycle, planted in October 2007 in a simple square lattice design and in plots consisting of three plants. The mean squares of their features revealed F-test significance for the effect of progeny, indicating that there is genetic variability to be explored in the next cycles. Estimates of heritability coefficients ranged from 19.54 to 71.38%. The averages of the main characteristics of agronomic importance in the studied population were higher than those of the controls, confirming the potential of the population to generate a superior population with the accumulation of favorable alleles in successive processes of selection. Estimates of genetic and phenotypic parameters of the main characteristics of economic importance reveal the possibility of success in the selection of superior progenies of yellow passion fruit, with the aim of registration and protection of a new cultivar.

Breeding methods and history of bean cultivars released in CBAB - Crop Breeding and Applied Biotechnology

Common bean is a staple food of great economic and social importance and breeding programs are being carried out in different institutions in Brazil and abroad. Aiming to determine how many new cultivars were presented in the journal CBAB - Crop Breeding and Applied Biotechnology and which breeding methods were used to develop the new genotypes, a historical survey of CBAB from 2001 to 2008 was carried out. During this period, 23 new common bean cultivars were described in CBAB, of which all but two that were bred at universities had been developed by public research institutes. The most commonly used breeding method was the pedigree, followed by bulk and the single pod descent (SPD) method. Since the preference of Brazilian consumers for carioca and black grain beans is noticeable, most bean breeders in the country have focused their research on these two bean types.

Estádios de desenvolvimento de mudas de umbuzeiros propagadas por enxertia

The economic importance of Spondias umbuzeiro has been increased in international market due to its exotic flavor and the ability to be used in juices, ice creams and other food preparation. For this reason, the knowledge of many aspects of this species is has been investigated by many researchers and also attracted the farmers interest. The aim of this research was to evaluate the development of umbu seedlings and to indicate the best stage of the seedling and also the more appropriate stage of the fork for grafting. Seeds were sown in wood beds with 1.5m wide10.0m long0.15m high, washed sand, and placed together and aligned in rows spaced 5.0cm apart. The following characteristics were evaluated: seedling size, leaves number, stem diameter at 5, 10 and 15cm from the soil, canopy and root fresh weight in the transplant date and also after 60, 120, 180 and 240 days after transplanting. The grafting technique studied consisted in a top bench grafting with seedlings from different origins and development stages. The efficiency of grafting technique was evaluated after 180 days after transplanting by observing the surviving plants. The experiments were carried out in a completely casualized design and the replicates made up of six plants per plot. It was concluded that from six months after transplanting the umbuzeiro seedlings can be grafted by using top cleft grafting. The efficiency of grafting technique reached 80% of all genotypes tested. The same results were observed considering plants after two months when the plants were already planting in a definitive place. The survival index decreased gradually when forks from plants older than six years were used.