ABSTRACT
Tepary bean (Phaseolus acutifolius A. Gray) is an underutilized drought tolerant annual legume, originating from the Sonoran Desert, that may be a beneficial forage/hay for beef cattle in the Southern Great Plains of the US (SGP). The SGP has erratic rainfall and periods of intermittent drought exacerbated by high summer temperatures. In 2020 and 2021, a split-plot design was used to evaluate 13 genotypes of tepary bean and a forage soybean (control) at El Reno, OK, USA to compare production of plant biomass and forage nutritive value parameters under seven harvest regimes. Genotypes were used as the main plot and cutting management as the sub-plot. Biomass production of all tepary bean genotypes equaled that of soybean (p > 0.05), while several genotypes had superior forage nutritive value traits (p ≤ 0.05). Overall, a 15-cm cutting height and 30-day harvest interval produced the best overall product (average dry biomass of 5.8 Mg ha-1 with average relative feed values (RFV) of 165). Although all harvest regimes reduced total seasonal biomass, forage nutritive value increased. However, the tradeoff between forage production and nutritive value may be unacceptable to most producers. Further agronomic and breeding research is needed to encourage producers to grow tepary bean as a forage/hay in the SGP.
Subject(s)
Phaseolus , Cattle , Animals , Phaseolus/genetics , Plant Breeding , GenotypeABSTRACT
The production of the common bean (Phaseolus vulgaris L.), one of the most important sources of protein and minerals and one of the most consumed grain legumes globally, is highly affected by heat and drought constraints. In contrast, the tepary bean (Phaseolus acutifolius A. Gray), a common bean-related species, is adapted to hot and dry climates. Hybridization to introduce complex traits from the tepary bean into the common bean has been challenging, as embryo rescue is required. In this study, we report three novel interspecific lines that were obtained by crossing lines from prior common bean × tepary bean hybridization with Phaseolus parvifolius Freytag in order to increase the male gametic diversity to facilitate interspecific crosses. These interspecific lines enhanced the crossability of the common bean and tepary bean species while avoiding the embryo rescue process. Crossing these three interspecific lines with tepary beans resulted in 12-fold more hybrid plants than crossing traditional common beans with tepary beans. Whole-genome sequencing analysis of these three interspecific lines shows large introgressions of genomic regions corresponding to P. parvifolius on chromosomes that presumably contribute to reproductive barriers between both species. The development of these lines opens up the possibility of increasing the introgression of desirable tepary bean traits into the common bean to address constraints driven by climate change.
ABSTRACT
KEY MESSAGE: The Common Bean Angular Leaf Spot Resistance Gene Phg-2 was fine-mapped to a 409-Kbp region, and molecular markers for breeders were developed and validated in field experiments. Common bean (Phaseolus vulgaris L.) is an important food legume in Latin America, Asia and Africa. It is an important source of protein, carbohydrates and micro-minerals, particularly for smallholder farmers. Common bean productivity is affected by angular leaf spot (ALS) disease caused by the pathogenic fungus Pseudocercospora griseola, resulting in significant yield losses, particularly in low-input smallholder farming systems in the tropics. The ALS resistance gene Phg-2, which was found in several highly resistant common bean genotypes, was investigated in crosses between Mesoamerican pre-breeding lines and elite Andean breeding lines. Next-generation sequencing (NGS) data sets were used to design new SNP-based molecular markers. The Phg-2 locus was confirmed to be the major locus providing ALS resistance in these crosses. The locus was fine-mapped to a 409-Kbp region on chromosome 8. Two clusters of highly related LRR genes were identified in this region, which are the best candidate genes for Phg-2. Molecular markers were identified that are closely linked to the Phg-2 resistance gene and also highly specific to the donor germplasm. Marker-assisted selection (MAS) was used to introgress the Phg-2 resistance locus into Andean breeding germplasm using MAB lines. The usefulness of molecular markers in MAS was confirmed in several field evaluations in complex breeding crosses, under inoculation with different ALS pathotypes. This project demonstrates that NGS data are a powerful tool for the characterization of genetic loci and can be applied in the development of breeding tools.
Subject(s)
Disease Resistance/genetics , Phaseolus/genetics , Plant Breeding , Plant Diseases/genetics , Ascomycota/pathogenicity , Chromosome Mapping , Genetic Markers , Genotype , Genotyping Techniques , Phaseolus/microbiology , Phenotype , Plant Diseases/microbiology , Polymorphism, Single Nucleotide , Sequence Analysis, DNAABSTRACT
Las deficiencias visuales en los escolares, pueden implicar problemas en el aprendizaje y retardo en el desarrollo psicosocial. Debido a la poca información sobre esta problemática en el Distrito, se realizo este estudio de tipo descriptivo, con el objeto de determinar la prevalencia de alteraciones oculares‐visuales, en una muestra de 1.250 niños de 5 a 14 años de establecimientos oficiales y privados en Bogotá. El 42% de los niños escolares presento algún grado de deficiencia en la AV (20/25 o menor). De deficiencia disminuye a medida que aumenta la edad. En cuanto a los defectos refractivos se presentaron: hipermetropía (59.2%), astigmatismo (28.2%), miopía (4.0% y emetropía (9.0%). De los niños que presentaban déficit de la AV, el 9.6% utilizaba corrección óptica. De los que presentaban algún grado de déficit de la AV y no usaban gafas al momento del examen, el 62% eran de colegios públicos y el 38% de colegios privados. Es necesario tanto identificar el problema de salud visual como revisar las estrategias de intervención, debido al impacto positivo que la solución a este problema puede generar especialmente en la población escolar.
The visual deficiencies in schoolchildren can imply learning problems and a delay in psychosocial development. Due to lack of information in this area in the District a descriptive type of study was conducted having as its objective to determine the prevalence of visual‐ocular alterations, in a sample of 1.250 children from 5 to 14 years of age in public and private schools in Bogota. Forty two (42%) percent of schoolchildren presented some degree of deficiency in the following were the results: hypermetry (59.2%), astigmatism (28.2%), myopia (4.0%) and emetropy (9.0%). Among children that presented a deficit of AV, 9.6% used optic correctives. Among those that represented some degree of AV deficit and didn´t use eyeglasses at the moment of the exam: 62% came from public schools and 38% from private school. It is necessary to identify the visual health problem and to review the intervention strategies given the positive impact of the solution that may generated, especially in the schoolchildren.
