RESUMO
Nutritionally enhanced beans (NEB) with more Fe and Zn than conventional beans (CB) and nutritionally enhanced maize (NEM) with more tryptophan and lysine than conventional maize (CM) were developed as part of a crop-biofortification strategy to improve human nutrition. Proxy measures were used to assess Fe and Zn bioavailability and protein digestibility of a bean recipe (fríjol sancochado) and a maize-milk recipe (mazamorra) prepared with enhanced or conventional crops in Colombia. Fe concentration was similar in the cooked NEB and CB and in NEM and CM (P> or = 0.05); in vitro Fe dialyzability was similar in cooked NEB (9.52%) and CB (9.72%) and greater for NEM (37.01%) than CM (32.24%). Zn concentration was higher in the uncooked and cooked NEB than in the CB (P < 0.05); phytate: Zn molar ratios were high in cooked NEB (36: 1) and CB (47: 1), suggesting low Zn bioavailability, and not different from each other (P = 0.07). There were no differences in Zn concentration or phytate: Zn molar ratio in the maize recipes. Nitrogen, tryptophan, and lysine concentrations were higher in the cooked NEM than CM; nitrogen was higher in the cooked NEB than CB (P < 0.05). In vitro protein digestibility was comparable (82% to 83%) for NEM and CM and higher for NEB (84%) than for CB (82%). The higher nutrient concentrations + similar bioavailability (protein in NEM, Zn in NEB), same nutrient concentrations + higher bioavailability (Fe in NEM) or higher nutrient concentrations + higher bioavailability (protein in NEB) can translate into more nutrients absorbed and utilized by the body.
Assuntos
Proteínas Alimentares/farmacocinética , Fabaceae/metabolismo , Alimentos Fortificados , Ferro da Dieta/farmacocinética , Zea mays/metabolismo , Zinco/farmacocinética , Disponibilidade Biológica , Pré-Escolar , Colômbia , Colorimetria , Dieta/métodos , Humanos , Lisina/metabolismo , Nitrogênio/metabolismo , Estado Nutricional/fisiologia , Valor Nutritivo , Ácido Fítico/metabolismo , Espectrofotometria Atômica , Triptofano/metabolismoRESUMO
The present study describes a new set of 61 polymorphic microsatellite markers for beans and the construction of a genetic map using the BAT93 x Jalo EEP558 (BJ) population for the purpose of developing a reference linkage map for common bean (Phaseolus vulgaris). The main objectives were to integrate new microsatellites on the existing framework map of the BJ population, and to develop the first linkage map for the BJ population based exclusively on microsatellites. Of the total of 264 microsatellites evaluated for polymorphism, 42.8% showed polymorphism between the genitors. An integrated map was created totaling 199 mapped markers in 13 linkage groups, with an observed length of 1358 cM and a mean distance between markers of 7.23 cM. For the map constructed exclusively with microsatellites, 106 markers were placed in 12 groups with a total length of 606.8 cM and average distance of 6.8 cM. Linkage group designation and marker order for BM microsatellites generally agreed with previous mapping, while the new microsatellites were well distributed across the genome, corroborating the utility of the BJ population for a reference map. The extensive use of the microsatellites and the availability of a reference map can help in the development of other genetic maps for common bean through the transfer of information of marker order and linkage, which will allow comparative analysis and map integration, especially for future quantitative trait loci and association mapping studies.
Assuntos
Mapeamento Cromossômico , Hibridização Genética , Repetições de Microssatélites/genética , Phaseolus/genética , Segregação de Cromossomos , Cromossomos de Plantas/metabolismo , Ligação Genética , Marcadores Genéticos , Repetições Minissatélites , Polimorfismo GenéticoRESUMO
The Andean gene pool of common bean (Phaseolus vulgaris L.) has high levels of morphological diversity in terms of seed color and size, growth habit and agro-ecological adaptation, but previously was characterized by low levels of molecular marker diversity. Three races have been described within the Andean gene pool: Chile, Nueva Granada and Peru. The objective of this study was to characterize a collection of 123 genotypes representing Andean bean diversity with 33 microsatellite markers that have been useful for characterizing race structure in common beans. The genotypes were from both the primary center of origin as well as secondary centers of diversity to which Andean beans spread and represented all three races of the gene pool. In addition we evaluated a collection of landraces from Colombia to determine if the Nueva Granada and Peru races could be distinguished in genotypes from the northern range of the primary center. Multiple correspondence analyses of the Andean race representatives identified two predominant groups corresponding to the Nueva Granada and Peru races. Some of the Chile race representatives formed a separate group but several that had been defined previously as from this race grouped with the other races. Gene flow was more notable between Nueva Granada and Peru races than between these races and the Chile race. Among the Colombian genotypes, the Nueva Granada and Peru races were identified and introgression between these two races was especially notable. The genetic diversity within the Colombian genotypes was high, reaffirming the importance of this region as an important source of germplasm. Results of this study suggest that the morphological classification of all climbing beans as Peru race genotypes and all bush beans as Nueva Granada race genotypes is erroneous and that growth habit traits have been mixed in both races, requiring a re-adjustment in the concept of morphological races in Andean beans.
Assuntos
Genes de Plantas , Variação Genética , Repetições de Microssatélites/genética , Phaseolus/classificação , Phaseolus/genética , DNA de Plantas , Pool Gênico , Genética Populacional , Genótipo , Phaseolus/crescimento & desenvolvimento , Filogenia , Polimorfismo GenéticoRESUMO
The present study describes a new set of 61 polymorphic microsatellite markers for beans and the construction of a genetic map using the BAT93 x Jalo EEP558 (BJ) population for the purpose of developing a reference linkage map for common bean (Phaseolus vulgaris). The main objectives were to integrate new microsatellites on the existing framework map of the BJ population, and to develop the first linkage map for the BJ population based exclusively on microsatellites. Of the total of 264 microsatellites evaluated for polymorphism, 42.8% showed polymorphism between the genitors. An integrated map was created totaling 199 mapped markers in 13 linkage groups, with an observed length of 1358 cM and a mean distance between markers of 7.23 cM. For the map constructed exclusively with microsatellites, 106 markers were placed in 12 groups with a total length of 606.8 cM and average distance of 6.8 cM. Linkage group designation and marker order for BM microsatellites generally agreed with previous mapping, while the new microsatellites were well distributed across the genome, corroborating the utility of the BJ population for a reference map. The extensive use of the microsatellites and the availability of a reference map can help in the development of other genetic maps for common bean through the transfer of information of marker order and linkage, which will allow comparative analysis and map integration, especially for future quantitative trait loci and association mapping studies.
Assuntos
Mapeamento Cromossômico , Hibridização Genética , Phaseolus/genética , Repetições de Microssatélites/genética , Segregação de Cromossomos , Cromossomos de Plantas/metabolismo , Ligação Genética , Marcadores Genéticos , Repetições Minissatélites , Polimorfismo GenéticoRESUMO
The bean pod weevil (Apion godmani Wagner) is a serious insect pest of common beans (Phaseolus vulgaris L.) grown in Mexico and Central America that is best controlled by host-plant resistance available in Durango or Jalisco genotypes such as J-117. Given unreliable infestation by the insect, the use of marker-assisted selection is desirable. In the present study, we developed a set of nine molecular markers for Apion resistance and mapped them to loci on chromosomes 2, 3, 4 and 6 (linkage groups b01, b08, b07 and b11, respectively) based on genetic analysis of an F (5:10) susceptible x resistant recombinant inbred line population (Jamapa x J-117) and two reference mapping populations (DOR364 x G19833 and BAT93 x JaloEEP558) for which chromosome and linkage group designations are known. All the markers were derived from randomly amplified polymorphic DNA (RAPD) bands that were identified through bulked segregant analysis and cloned for conversion to sequence tagged site (STS) markers. One of the markers was dominant while four detected polymorphism upon digestion with restriction enzymes. The other markers were mapped as RAPD fragments. Phenotypic data for the population was based on the evaluation of percentage seed damage in replicated trials conducted over four seasons in Mexico. In single point regression analysis, individual markers explained from 3.5 to 22.5% of the variance for the resistance trait with the most significant markers overall being F10-500S, U1-1400R, R20-1200S, W9-1300S and Z4-800S, all markers that mapped to chromosome 2 (b01). Two additional significant markers, B1-1400R and W6-800R, were mapped to chromosome 6 (b11) and explained from 4.3 to 10.2% of variance depending on the season. The latter of these markers was a dominant STS marker that may find immediate utility in marker-assisted selection. The association of these two loci with the Agr and Agm genes is discussed as well as the possibility of additional resistance genes on chromosome 4 (b07) and chromosome 3 (b08). These are among the first specific markers developed for tagging insect resistance in common bean and are expected to be useful for evaluating the mechanism of resistance to A. godmani.
Assuntos
Mapeamento Cromossômico , Phaseolus , Gorgulhos/patogenicidade , Animais , América Central , Cruzamentos Genéticos , Feminino , Ligação Genética , Marcadores Genéticos , México , Phaseolus/genética , Phaseolus/parasitologia , Polimorfismo Genético , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
Advanced backcross QTL analysis was used to identify quantitative trait loci (QTL) for agronomic performance in a population of BC2F(3:5) introgression lines created from the cross of a Colombian large red-seeded commercial cultivar, ICA Cerinza, and a wild common bean accession, G24404. A total of 157 lines were evaluated for phenological traits, plant architecture, seed weight, yield and yield components in replicated trials in three environments in Colombia and genotyped with microsatellite, SCAR, and phaseolin markers that were used to create a genetic map that covered all 11 linkage groups of the common bean genome with markers spaced at an average distance of every 10.4 cM. Segregation distortion was most significant in regions orthologous for a seed coat color locus (R-C) on linkage group b08 and two domestication syndrome genes, one on linkage group b01 at the determinacy (fin) locus and the other on linkage group b02 at the seed-shattering (st) locus. Composite interval mapping analysis identified a total of 41 significant QTL for the eight traits measured of which five for seed weight, two for days to flowering, and one for yield were consistent across two or more environments. QTL were located on every linkage group with b06 showing the greatest number of independent loci. A total of 13 QTL for plant height, yield and yield components along with a single QTL for seed size showed positive alleles from the wild parent while the remaining QTL showed positive alleles from the cultivated parent. Some QTL co-localized with regions that had previously been described to be important for these traits. Compensation was observed between greater pod and seed production and smaller seed size and may have resulted from QTL for these traits being linked or pleiotropic. Although wild beans have been used before to transfer biotic stress resistance traits, this study is the first to attempt to simultaneously obtain a higher yield potential from wild beans and to analyze this trait with single-copy markers. The wild accession was notable for being from a unique center of diversity and for contributing positive alleles for yield and other traits to the introgression lines showing the potential that advanced backcrossing has in common bean improvement.