Evaluación de características agronómicas y severidad de enfermedades foliares de tres híbridos comerciales y cinco híbridos triples avanzados de maíz amarillo duro

Field experiments were conducted to evaluate agronomic traits and response to foliar fungal diseases of five advanced triple hybrids of hard yellow maize (Zea mays L.) and three commercial hybrids. An A × B factorial experiment was used with eight treatments, four repetitions and the Tukey test to compare means of the treatments (P>0.05). The most limiting disease is rust. The agronomic characteristics of breeding lines: h1, h2, h3, h4 and h5 (triple hybrids) were evaluated and compared with h6, h7, and h8 (commercial hybrids). Field trials were conducted in two locations of Central Coast of Ecuador (Quevedo and Balzar). Both locations showed significant differences for agronomic traits; Balzar presented lower yield (6,205.46 kg ha-1) and greater severity of curvularia leaf spot (3.34 CIMMYT scale) compared to Quevedo (7,368.21 kg ha-1) and (2.47 CIMMYT scale). For hybrids, h6 had significantly lower yield (5,306.83 kg ha-1), compared to h5 (6,914.09 kg ha-1), h1 (7211, 80 kg ha-1), and h3 (7,266.83 kg ha-1), and h8 (8036.85 kg ha-1). Significant differences were also detected for the orthogonal comparison (INIAP hybrids) with 5,634.44 kg ha-1 and the promissory lines with 6,997.68 kg ha-1. The highest net profit was achieved with the hybrid h2 with US$1,405.76 followed by the hybrid h1 with US$1,385,92, obtaining a Benefit - Cost ratio of 2.32 and 2.30 respectively, which indicates that for each monetary unit invested 1.32 and 1.30 additional or profit was obtained for the two hybrids, respectively.Se realizaron experimentos de campo para evaluar las características agronómicas y la respuesta a las enfermedades fúngicas foliares de cinco híbridos triples avanzados de maíz amarillo duro (Zea mays L.) y tres híbridos comerciales. Se utilizó un experimento factorial A × B con ocho tratamientos, cuatro repeticiones y la prueba de Tukey para comparar las medias de los tratamientos (P>0.05). La enfermedad más limitante es la roya. Se evaluaron las características agronómicas de líneas mejoradas: h1, h2, h3, h4 y h5 (híbridos triples) y se compararon con h6, h7 y h8 (híbridos comerciales). Se realizaron experimentos en dos localidades de la costa central de Ecuador (Quevedo y Balzar). Ambas localidades mostraron diferencias significativas para las características agronómicas; Balzar presentó menor rendimiento (6.205,46 kg ha-1) y mayor severidad de la mancha foliar por curvularia (escala CIMMYT 3,34) en comparación con Quevedo (7368,21 kg ha-1) y (escala CIMMYT 2,47). Para los híbridos, h6 tuvo un rendimiento significativamente menor (5306,83 kg ha-1), en comparación con h5 (6914,09 kg ha-1), h1 con (7211, 80 kg ha-1), y h3 (7266,83 kg ha-1), y h8 (8036,85 kg ha-1). También se detectaron diferencias significativas para la comparación ortogonal (híbridos INIAP) con 5.634,44 kg ha-1 y las líneas promisorias con 6.997,68 kg ha-1. La mayor utilidad neta se logró con el híbrido h2 con US1.405,76 seguido del híbrido h1 con US$1.385,92, obteniendo una relación Beneficio - Costo de 2,32 y 2,30 respectivamente, lo que indica que por cada unidad monetaria invertida$ 1,32 y 1,30 adicionales o se obtuvo ganancia para los dos híbridos, respectivamente

Identification of resistance loci toward Phytophthora sojae in South Korean soybean plant introductions 407974B and 424487B

Phytophthora root and stem rot is a major constraint to soybean [Glycine max (L.) Merr.] production worldwide. Deployment of single dominant Resistance to Phytophthora sojae (Rps) genes are an effective management strategy for this disease. However, due to increasing diversity in P. sojae populations for pathotype, new effective Rps genes are needed. Two recombinant inbred line (RIL) populations, each derived from a cross with Williams (susceptible) and resistant accessions PI 407974B and PI 424487B, were evaluated for resistance with one or more P. sojae pathotypes: OH1 (vir 7), OH4 (vir 1a, 1c, 7), OH7 (vir 1a, 3a, 3c, 4, 5, 6, 7), OH25 (vir 1a, 1b, 1c, 1k, 7), and 1.S.1.1 (1a, 1b, 1k, 2, 3a, 3c, 4, 5, 6, 7, 8). Molecular maps were assembled with BARCSoySNP6K BeadChip, simple-sequence repeat, and Kompetitive Allele Specific polymerase chain reaction markers. A total of three Rps loci were mapped, one near Rps1 on Chromosome 3 and two near Rps4/6 on chromosome 18. Quantitative trait loci and straight linkage maps confirmed the loci. Resistance to P. sojae pathotypes 1.S.1.1 and/or OH7 was mapped to Chromosome 3 in the PI 407974B RIL population. PI 407974B and PI 424487B RIL populations have Rps loci on chromosome 18 toward OH4 and OH25, respectively, which are near the Rps4/6 region. Although these PIs may have novel Rps genes/alleles and could assist in the deployment and pyramiding of resistance against P. sojae, care should be taken because these may condition defense reactions to some P. sojae pathotypes but not to all.Funding for this project was provided by the United Soybean Board, the Ohio Soybean Council, and the Ohio State University Center for Applied Plant Sciences, College of Food, Agricultural and Environmental Sciences, Center for Soybean Research. In addition, we wish to acknowledge support from the Molecular Cellular Imaging Center at Ohio Agricultural Research and Development Center. Salaries and research support for this project was provided by State and Federal Funds appropriated to the Ohio Agricultural Research and Development Center, The Ohio State University and the National Institute of Food and Agriculture, USDA, Hatch projects Development of Disease Management Strategies for Soybean Pathogens in Ohio OHO01303 and Genetic Analysis of Soybean Added-Value Traits and Soybean Variety Development for Ohio OHO01279

Factores asociados al crecimiento y producción de semilla pre-básica en diez variedades de papa nativas bajo el sistema aeropónico en Kishuara – Perú.

This experiment was carried out in the greenhouse of the sub-region agrarian direction at Kishuara district in the province of Andahuaylas of the Apurimac region of Peru under the aeroponic production system. Growth-associated factors and pre-basic seed production were evaluated in ten varieties of native potatoes using aeroponic conditions in Kishuara - Peru. A complete randomized blocks design was used, and the experimental unit consisted of 12 plants spaced at 20 cm x 18 cm. The variables under study were: height of the plant (average of 12 sampling plants), days to the tuber formation, survival rate (%), days to senescence of the plant, diameter of the stem at senescence, days to the first harvest, yield, number of tubers per plant, and the average weight of tubers. Huayro variety reached the highest growth in plant height (133 cm), the highest yield (981 g / plant), and the highest average weight of mini tubers/plant (12.5 g / plant). The Q'ompis variety was the most precocious (39 days to tuber formation). The days to the first harvest were 96 days for the varieties: Duraznillo, Yana Suytu, Q'ompis and Camotillo, and 125 in Q’eq’orani. Huayro seems to be the best variety to be used for generation of new cultivars and exploitation as native variety for potato seed tuber under aeroponic production system. Our study open the possibility for production of best quality pre-basic seed for native potato production in Peru.La investigación se llevó a cabo en el invernadero aeropónico de Kishuará –Perú. Se evaluó el comportamiento (crecimiento, características de desarrollo, así como rendimiento) de 10 variedades de papas nativas en la producción de semilla pre-básica bajo el sistema aeropónico. La unidad experimental estuvo conformada por 12 plantas distanciadas a 20 cm. x 18 cm. Se empleó el Diseño de Bloques Completos al Azar. Las variables en estudio fueron: altura de planta (promedio de 12 plantas), días a la tuberización, porcentaje de sobrevivencia, días a la senescencia de la planta, diámetro de tallo en la senescencia, días a la primera cosecha, rendimiento y número de tubérculos por planta y peso promedio de tubérculos. La variedad Huayro alcanzó el mayor crecimiento en altura de planta (133 cm), el mayor rendimiento (981 g/planta), y el mayor peso promedio de mini tubérculos / planta (12.5 g/planta). La variedad Q’ompis fue la más precoz (39 días a la tuberización). Las variedades: Duraznillo, Yana shuito, Q’ompis y Camotillo presentaron 96 días hasta la primera cosecha mientras que en la variedad Q’eq’orani la primera cosecha se realizó a los 125 días. La variedad Huayro aparece como promisoria para generar nuevos cultivares, así como para su explotación en la producción de semilla aeroponica. Nuestro estudio abre la posibilidad de producción de semilla prebásica de mejor calidad para la producción de papa nativa en Per