Can we abandon phosphorus starter fertilizer in maize? Results from a diverse panel of elite and doubled haploid landrace lines of maize (Zea mays L.)

The importance of phosphorus (P) in agriculture contrasts with the negative environmental impact and the limited resources worldwide. Reducing P fertilizer application by utilizing more efficient genotypes is a promising way to address these issues. To approach this, a large panel of maize (Zea mays L.) comprising each 100 Flint and Dent elite lines and 199 doubled haploid lines from six landraces was assessed in multi-environment field trials with and without the application of P starter fertilizer. The treatment comparison showed that omitting the starter fertilizer can significantly affect traits in early plant development but had no effect on grain yield. Young maize plants provided with additional P showed an increased biomass, faster growth and superior vigor, which, however, was only the case under environmental conditions considered stressful for maize cultivation. Importantly, though the genotype-by-treatment interaction variance was comparably small, there is genotypic variation for this response that can be utilized in breeding. The comparison of elite and doubled haploid landrace lines revealed a superior agronomic performance of elite material but also potentially valuable variation for early traits in the landrace doubled haploid lines. In conclusion, our results illustrate that breeding for P efficient maize cultivars is possible towards a reduction of P fertilizer in a more sustainable agriculture

Detection of segregation distortion loci in triticale (x Triticosecale Wittmack) based on a high-density DArT marker consensus genetic linkage map

<p>Abstract</p> <p>Background</p> <p>Triticale is adapted to a wide range of abiotic stress conditions, is an important high-quality feed stock and produces similar grain yield but more biomass compared to other crops. Modern genomic approaches aimed at enhancing breeding progress in cereals require high-quality genetic linkage maps. Consensus maps are genetic maps that are created by a joint analysis of the data from several segregating populations and different approaches are available for their construction. The phenomenon that alleles at a locus deviate from the Mendelian expectation has been defined as segregation distortion. The study of segregation distortion is of particular interest in doubled haploid (DH) populations due to the selection pressure exerted on the plants during the process of their establishment.</p> <p>Results</p> <p>The final consensus map, constructed out of six segregating populations derived from nine parental lines, incorporated 2555 DArT markers mapped to 2602 loci (1929 unique). The map spanned 2309.9 cM with an average number of 123.9 loci per chromosome and an average marker density of one unique locus every 1.2 cM. The R genome showed the highest marker coverage followed by the B genome and the A genome. In general, locus order was well maintained between the consensus linkage map and the component maps. However, we observed several groups of loci for which the colinearity was slightly uneven. Among the 2602 loci mapped on the consensus map, 886 showed distorted segregation in at least one of the individual mapping populations. In several DH populations derived by androgenesis, we found chromosomes (2B, 3B, 1R, 2R, 4R and 7R) containing regions where markers exhibited a distorted segregation pattern. In addition, we observed evidence for segregation distortion between pairs of loci caused either by a predominance of parental or recombinant genotypes.</p> <p>Conclusions</p> <p>We have constructed a reliable, high-density DArT marker consensus genetic linkage map as a basis for genomic approaches in triticale research and breeding, for example for multiple-line cross QTL mapping experiments. The results of our study exemplify the tremendous impact of different DH production techniques on allele frequencies and segregation distortion covering whole chromosomes.</p

Incidencia de la enseñanza problémica en el logro de las competencias del área de educación física en los alumnos del 5to de secundaria de la educación básica regular-2013

TesisUniversidad Nacional de Educación Enrique Guzmán y Valle. Escuela de Posgrado.La presente investigación tiene como propósito explicar la incidencia de la enseñanza problémica en el logro de las competencias del área de educación física en los alumnos del 5to de secundaria de la educación básica regular-2013, se utilizó un diseño cuasi experimental con una muestra de 30 estudiantes a quienes se les aplicó tres instrumentos de evaluación para cada una de las competencias: construye su corporeidad, valora y practica actividades físicas y hábitos saludables; utiliza sus habilidades socio motrices en actividades físicas y deportivas. Estos instrumentos fueron sometidos al análisis respectivo y opinión favorable de expertos en la materia, las que determinaron que la pruebas son válidas y confiables, por tanto los resultados de la investigación indican que existen mejo-rías luego de aplicar la enseñanza problémica en las competencias del área de educación física. Los resultados de investigación de la hipótesis general demuestran que el valor de significancia del estadístico es menor que 0,05, entonces podemos asegurar que el coeficiente de correlación es significativo (p < 0,05). Por lo tanto, se rechaza la hipótesis nula (Ho) y se acepta la hipótesis alternativa (H1). Esto quiere decir que: Sí se aplica la enseñanza problémica, entonces, mejorará significativamente el logro de las competencias del área de educación física, en los alumnos de 5to de secundaria de la educación básica regular de la institución educativa N° 6069 Pachacutec, ubicada en el distrito de Villa el Salvador, durante el tercer bimestre del año 2013

Wuerschum_and_Kraft_Data

Phenotypic and genotypic data underlying this stud

Wuerschum_and_Kraft_genetic_map

Genetic linkage map underlying this stud

Inheritance of Sclerotinia Midstalk Rot Resistance in Elite Sunflower Breeding Germplasm NonCommercial-NoDerivatives 3.0 License. (CC BY-NC-ND 3.0) Publication History

Abstract Sclerotinia sclerotiorum (Lib.) de Bary is a yield-limiting factor and the major disease of sunflower (Helianthus annuus L.) in the temperate regions of the world. In this study, we characterized resistance to S. sclerotiorum midstalk rot and morphological traits in a population derived from a cross between two Sclerotinia resistant lines. Phenotypic data for 114 F3:4 lines and the two parents, NDBLOSsel and K04, were obtained under artificial infection in field experiments which yielded moderate to high heritabilities. Our results suggest that S. sclerotiorum resistance is highly quantitative and that different genomic regions may mediate the resistance in different tissues of the plant. We found transgressive segregation for all three resistance traits suggesting that both resistant parents carried complementary QTL. In addition, we investigated the segregation of two known QTL for midstalk resistance and found that one of them also acts as a major QTL in this cross between two resistant lines. Collectively, our results suggest that a QTL stacking approach is a promising way to increase resistance to S. sclerotiorum in elite sunflower germplasm

Identification and Fine-Mapping of Quantitative Trait Loci Controlling Plant Height in Central European Winter Triticale (×Triticosecale Wittmack)

The quantitatively inherited trait plant height is routinely evaluated in triticale breeding programs as it substantially influences lodging and disease susceptibility, is a main contributor to biomass yield, and is required to improve hybrid seed production by fine-tuning plant height in the female and male parental pools in hybrid breeding programs. In this study, we evaluated a panel of 846 diverse Central European triticale genotypes to dissect the genetic architecture underlying plant height by genome-wide association mapping. This revealed three medium- to large-effect QTL on chromosomes 5A, 4B, and 5R. Genetic and physical fine-mapping of the putative QTL revealed that the QTL on chromosome 5R most likely corresponds to Ddw1 and that the QTL on chromosome 5A is likely to be Rht12. Furthermore, we observed a temporal trend in registered cultivars with a decreasing plant height during the past decades, accompanied by an increasing use of the height-reducing alleles at the identified QTL. In summary, our results shed new light on the genetic control of plant height in triticale and open new avenues for future improvement by breeding

Do We Need to Breed for Regional Adaptation in Soybean?—Evaluation of Genotype-by-Location Interaction and Trait Stability of Soybean in Germany

Soybean is a crop in high demand, in particular as a crucial source of plant protein. As a short-day plant, soybean is sensitive to the latitude of the growing site. Consequently, varieties that are well adapted to higher latitudes are required to expand the cultivation. In this study, we employed 50 soybean genotypes to perform a multi-location trial at seven locations across Germany in 2021. Two environmental target regions were determined following the latitude of the locations. Adaptation and trait stability of seed yield and protein content across all locations were evaluated using Genotype plus Genotype-by-Environment (GGE) biplots and Shukla’s stability variance. We found a moderate level of crossing-over type genotype-by-location interaction across all locations. Within the environmental target regions, the genotype-by-location interaction could be minimised. Despite the positive correlation (R = 0.59) of seed yield between the environmental target regions and the same best-performing genotype, the genotype rankings differed in part substantially. In conclusion, we found that soybean can be grown at a wide range of latitudes across Germany. However, the performance of genotypes differed between the northern and southern locations, with an 18.8% higher mean yield in the south. This in combination with the observed rank changes of high-performing genotypes between both environmental target regions suggests that selection targeted towards environments in northern Germany could improve soybean breeding for those higher latitude regions