Examinando por Autor "Ortiz, Rodomiro"

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Genomic insights into Lolium multiflorum diversity for forage breeding in Andean livestock systems
(Frontiers Media S.A., 2026-06-10) Bobadilla , Leidy G.; Ortiz, Rodomiro; Castillo, Gianmarco; Matías, Felipe; Gutiérrez, Lucía; Valqui, Leandro; Carrasco Chilón, William Leoncio; Díaz Valderrama, Jorge R.; Venancio, Thiago M.; Alava, E.I.; Castillo, Miguel S.; Vásquez, Héctor V.
Understanding the genetic diversity of Lolium multiflorum is essential for developing targeted breeding programs that can effectively support pasture-based livestock systems in the Peruvian Andean. This study assessed genomic variability and population structure in 27 L. multiflorum accessions from the Cajamarca region and the INIA Amazonas germplasm bank (Peru), using the genotyping-by-sequencing (GBS) technique. DNA extracted from young leaves was sequenced on an Illumina NovaSeq 6000 platform. After bioinformatic processing, 2,070 single nucleotide polymorphisms (SNPs) with heterogeneous distribution were obtained across seven chromosomes. A Principal Coordinate and an Unweighted Pair Group Method with Arithmetic Mean analyses revealed two distinct genetic groups were identified, reflecting a complex structure shaped by gene flow and local selection. The analysis of molecular variance showed that 90% of the genetic variation occurs within populations, whereas the remaining 10% corresponds to interregional differences (PhiPT = 0.099, p < 0.006). The negative Inbreeding Coefficient (F_IS) values (Cajamarca = -0.2312; Amazonas = -0.5489) indicate an excess of heterozygotes, a pattern typically associated with predominantly outcrossing species. Additionally, high observed heterozygosity (Ho > 0.57) points to potential hybrid vigor and indicates that these populations may maintain stable genetic equilibrium. Collectively, these findings demonstrate that Peruvian L. multiflorum harbors a broad genetic base, shaped by historical germplasm exchange and local environmental adaptation. This diversity provides critical insights for conservation strategies and can supports breeding programs aimed at enhancing forage resilience and productivity in high-Andean ecosystems.
Population structure and diversity of common bean (Phaseolus vulgaris L.) landraces in the Peruvian Amazon
(Public Library of Science (PLOS) — San Francisco, CA, Estados Unidos de América, 2026-07-20) Tobaru, Jorge; Barrera Lozano, Marvin; Vecco Giove, Carlos; Peláez, Jorge; Pinchi, Mack; Vargas, Yesenia; Chuquillanqui, Jorge; Soto Torres, Julian; Robles, Ronald; Saravia Navarro, David; Petroli, Cesar; Etchevers, Jorge; Ortiz, Rodomiro; Blas, Raul
Common bean (Phaseolus vulgaris L.) is a globally important grain legume, yet the genetic diversity of landraces from the Peruvian Amazon remains poorly characterized. This study aimed to assess the population structure and genetic diversity of Amazonian common bean by integrating morphological and genome-wide SNP data. A total of 476 accessions were phenotyped using 18 morphological traits, and 647 accessions were genotyped with 23,050 high-quality DArTseq SNP markers. Cluster and population structure analyses consistently identified two major genetic groups corresponding to the Andean (n = 284) and Mesoamerican (n = 363) gene pools, with further subdivision into four subgroups at K = 4. Principal Coordinate Analysis supported this structure, with the first axis explaining 62.62% of the variation in the molecular data. Genetic diversity was high, with 94.9% of SNPs successfully mapped and more than 94% of loci polymorphic in both groups. However, observed heterozygosity was low (Ho = 0.035–0.041) compared to expected heterozygosity (He ≈ 0.147–0.148), and inbreeding coefficients were high (FIS = 0.52–0.54), consistent with the predominantly self-pollinating mating system. Hill number analyses indicated similar allelic richness between groups (q = 0: α ≈ 1.95–1.97) and low differentiation in allele presence (β = 1.04), whereas differentiation increased when allele frequencies were considered (q = 2: β ≈ 1.4–1.5). Morphological analyses revealed substantial phenotypic variation, including flowering time (32–75 days), pod length (6.5–17.3 cm), and number of locules per pod (2–11), and identified four distinct phenotypic clusters. No redundant accessions were detected. These results indicate that Amazonian landraces harbor high levels of genetic and phenotypic diversity structured by gene pool origin and local adaptation. The integration of morphological and SNP data provides a robust framework for germplasm characterization and highlights the importance of conserving these genetic resources for future breeding and sustainable agriculture.