Beat Keller

Last Name

Keller

First Name

Beat

ORCID

0000-0001-5852-6660

Organisational unit

03894 - Walter, Achim / Walter, Achim

Show all metadata

Search Results

Publications 1 - 10 of 12

Swiss agriculture can become more sustainable and self-sufficient by shifting from forage to grain legume production
Keller, Beat; Oppliger, Corina; Chassot, Mirjam; et al. (2024)
Communications Earth & Environment
Switzerland’s livestock production causes high environmental costs and depends strongly on feed imports. While plant-based protein demand increases, the local grain legume production is negligible (~ 9000 hectares). Here, we investigated the potential of sustainable legume protein production based on an expert survey followed by a quantitative analysis based on yield, soil, terrain and climate data. Pea, soybean and faba bean showed high potential for Swiss agriculture given adaptions in policy, pricing and breeding. The potential grain legume production area was 107,734 hectares on suitable arable land (Scenario I). Switzerland’s self-sufficiency could be increased by cutting imports and maximizing legume production on 181,479 hectares (Scenario II) in expense of grassland and fodder maize. This would replace approximately 41% of animal protein consumption with plant-based protein, preserving 32% of milk and 24% of meat protein. In conclusion, domestic legume production could be substantially increased while improving human and environmental health.
Thermal imaging can reveal variation in stay-green functionality of wheat canopies under temperate conditions
Anderegg, Jonas; Kirchgessner, Norbert; Aasen, Helge; et al. (2024)
Frontiers in Plant Science
Canopy temperature (CT) is often interpreted as representing leaf activity traits such as photosynthetic rates, gas exchange rates, or stomatal conductance. This interpretation is based on the observation that leaf activity traits correlate with transpiration which affects leaf temperature. Accordingly, CT measurements may provide a basis for high throughput assessments of the productivity of wheat canopies during early grain filling, which would allow distinguishing functional from dysfunctional stay-green. However, whereas the usefulness of CT as a fast surrogate measure of sustained vigor under soil drying is well established, its potential to quantify leaf activity traits under high-yielding conditions is less clear. To better understand sensitivity limits of CT measurements under high yielding conditions, we generated within-genotype variability in stay-green functionality by means of differential short-term pre-anthesis canopy shading that modified the sink:source balance. We quantified the effects of these modifications on stay-green properties through a combination of gold standard physiological measurements of leaf activity and newly developed methods for organ-level senescence monitoring based on timeseries of high-resolution imagery and deep-learning-based semantic image segmentation. In parallel, we monitored CT by means of a pole-mounted thermal camera that delivered continuous, ultra-high temporal resolution CT data. Our results show that differences in stay-green functionality translate into measurable differences in CT in the absence of major confounding factors. Differences amounted to approximately 0.8 degrees C and 1.5 degrees C for a very high-yielding source-limited genotype, and a medium-yielding sink-limited genotype, respectively. The gradual nature of the effects of shading on CT during the stay-green phase underscore the importance of a high measurement frequency and a time-integrated analysis of CT, whilst modest effect sizes confirm the importance of restricting screenings to a limited range of morphological and phenological diversity.
The environment exerts a greater influence than the transgene on the transcriptome of field-grown wheat expressing the Pm3b allele
Diaz Quijano, Carolina; Brunner, Susanne; Keller, Beat; et al. (2015)
Transgenic Research
Wheat provides 20 % of the calories consumed worldwide. Powdery mildew infections of wheat can result in more than 30 % yield loss but it has been demonstrated that wheat overexpressing Pm3b, an allele of the R gene Pm3, has enhanced resistance against powdery mildew under field conditions. A gene expression profile study using GeneChip Wheat Genome Array and Fluidigm 96.96 Dynamic Arrays was performed to obtain insights into the mode of action of Pm3b and to elucidate the molecular basis of pleiotropic effects observed in three out of four independent transgenic events under field conditions. A cluster analysis of the microarray data and a principal component analysis of the Fluidigm 96.96 Dynamic Arrays data showed that transgenic lines and null segregants grouped together. The microarray analysis of samples from fungicide-treated plants revealed that significantly fewer genes were differentially expressed in Pm3b#1 than in Pm3b#2, which had a pleiotropic phenotype in the field, compared to their null segregants. Together, our data provide evidence that the environment influenced gene expression in the Pm3b lines more than the transgene itself.
Genetic architecture and genomic predictive ability of apple quantitative traits across environments
Jung, Michaela; Keller, Beat; Roth, Morgane; et al. (2022)
Horticulture Research
Genetic analysis of resistance to bean leaf crumple virus identifies a candidate LRR-RLK gene
Ariza-Suarez, Daniel; Keller, Beat; Spescha, Anna; et al. (2023)
The Plant Journal
Bean leaf crumple virus (BLCrV) is a novel begomovirus infecting common bean (Phaseolus vulgaris L.), threatening bean production in Latin America. Genetic resistance is required to ensure yield stability and reduce the use of insecticides, yet the available resistance sources are limited. In this study, three common bean populations containing a total of 559 genotypes were evaluated in different yield and BLCrV resistance trials under natural infection in the field. A genome-wide association study identified the locus BLC7.1 on chromosome Pv07 at 3.31 Mbp, explaining between 8.22% to 16.08% of the phenotypic variation for BLCrV resistance. Comparatively, whole-genome regression models explained 51% to 78% of the variation and identified the same region on Pv07 to confer the resistance. The most significantly associated markers were located within the gene model Phvul.007G040400, which encodes a leucine-rich repeat receptor-like kinase subfamily III member and is likely involved in the innate immune response against the virus. The allelic diversity within this gene revealed five different haplotype groups, one of which was significantly associated with BLCrV resistance. As the same genome region was previously reported with resistance against other geminiviruses affecting common bean, our study highlights the role that historical breeding for virus resistance has played in the accumulation of positive alleles against newly emerging viruses. In addition, we provide novel diagnostic SNP markers for marker-assisted selection to exploit BLC7.1 for breeding against geminivirus diseases in one of the most important food security crops worldwide.
Linking photosynthesis and yield reveals a strategy to improve light use efficiency in a climbing bean breeding population
Keller, Beat; Soto, Jonatan; Steier, Angelina; et al. (2024)
Journal of Experimental Botany
Photosynthesis drives plant physiology, biomass accumulation and yield. Photosynthetic efficiency, specifically the operating efficiency of photosystem II (F_q’/F_m’), is highly responsive to actual growth conditions, especially to fluctuating photosynthetic photon fluence rate (PPFR). Under field conditions, plants constantly balance energy uptake to optimize growth. The dynamic regulation complicates the quantification of cumulative photochemical energy uptake based on the intercepted solar energy, its transduction into biomass and the identification of efficient breeding lines. Here, we show significant effects on biomass related to genetic variation in photosynthetic efficiency of 178 climbing bean (Phaseolus vulgaris L.) lines. Under fluctuating conditions, the F_q’/F_m’ was monitored throughout the growing period using hand-held and automated chlorophyll fluorescence phenotyping. The seasonal response of F_q’/F_m’ to PPFR (Response_G:PPFR) achieved significant correlations with biomass and yield ranging from 0.33 to 0.35 and 0.22 to 0.31 in two glasshouse and three field trials, respectively. Phenomic yield prediction outperformed genomic predictions for new environments in four trials under rather different growing conditions. Investigating genetic control over photosynthesis, one SNP (Chr09_37766289_13052) on chromosome 9 was significantly associated with ResponseG:PPFR in proximity to a candidate gene controlling chloroplast thylakoid formation. In conclusion, photosynthetic screening facilitates and accelerates selection for high yield potential.
Low Outcrossing from an Apple Field Trial Protected with Nets
Schlathölter, Ina; Dalbosco, Anna; Meissle, Michael; et al. (2021)
Agronomy
Regulatory compliance of experimental releases into the environment of not yet approved genetically modified plants often requires implementation of measures to reduce the dispersal of reproductive material. To study the impact of nets on pollen flow in an experimental field site in Switzerland, non-GM apple varieties ‘Ladina’ and ’Nicogreen’ were planted inside and outside a netted plot, respectively. Seeds harvested from mature fruits were germinated and the paternal variety of the seedlings was determined using simple sequence repeat (SSR) molecular markers. We demonstrate that pollination frequency from trees inside the netted plot to trees outside over a two-year (2018 and 2019) study of 4500 seedlings is 0.6% (26 seedlings). Moreover, these outcrossing events decreased with increasing distance from the pollen donor. Over the study period, we found on average 0.9%, 0.5%, 0.4% and 0.09% of the seedlings derived from apples of ‘Nicogreen’ trees at 8 m, 15 m, 72 m and 117 m being generated by fertilisations of ‘Ladina’ pollen, respectively. In comparison, 48.3% (2018 season) and 75.1% (2019 season) of examined ‘Ladina’ seedlings in the netted plot originated from ‘Nicogreen’ tree pollen outside the netted plot. The results suggest that insect netting is effective in minimizing egress of apple pollen from an experimental site and that the likelihood of outcrossing is reduced further (<0.1%) when there are no compatible apple trees within a radius of 100 m of the pollen donor. These data are important for biosafety research/regulation to aid understanding of pollen flow in experimental field sites.
The genetic basis of apple shape and size unraveled by digital phenotyping
Keller, Beat; Jung, Michaela; Bühlmann-Schütz, Simone; et al. (2023)
bioRxiv
Great diversity of shape, size, and skin color is observed among the fruits of different apple genotypes. These traits are critical for consumers and therefore interesting targets for breeding new apple varieties. However, they are difficult to phenotype and their genetic basis, especially for fruit shape and ground color, is largely unknown. We used the fruit FruitPhenoBox to digitally phenotype 506 genotypes of the apple reference population (apple REFPOP) genotyped for 303,148 single nucleotide polymorphism (SNP) markers. From the apple images, 573 highly heritable features describing fruit shape and size as well as 17 highly heritable features for fruit skin color were extracted to explore genotype-phenotype relationships. Out of these features, nine and four principal components (PCs) as well as 16 and eight uncorrelated features were chosen to carry out genome-wide association studies for fruit shape, size, and fruit skin color, respectively. In total, 69 SNPs scattered over all 17 apple chromosomes were significantly associated with round, conical, cylindrical, or symmetric fruit shapes and fruit size. Novel associations with major effect on round or conical fruit shapes and fruit size were identified on chromosomes 1 and 2. Additionally, 16 SNPs associated with PCs and uncorrelated features related to red over color as well as green and yellow ground color were found on eight chromosomes. The identified associations can be used to advance marker-assisted selection in apple fruit breeding to systematically select for desired fruit appearance.
Investigating pea (Pisum sativum L.) flowering with high throughput field phenotyping and object detection
Oppliger, Corina; Zenkl, Radek; Walter, Achim; et al. (2025)
Smart Agricultural Technology
Flowering is one of the most important and sensitive processes throughout a plant's life and marks the start of the reproductive phase. Flowering traits largely define yield potential and are therefore crucial for crop breeding. To observe flowering dynamics under field conditions, visual ratings have been a standard method for decades. Today, high-throughput field phenotyping (HTFP) methods provide opportunities for objective and efficient data collection. We developed an object detection approach (based on YOLOv8) that allows to collect detailed data about flower and pod density. RGB-images from 12 pea breeding lines were automatically acquired by the field phenotyping platform (FIP) of ETH Zurich in two years. The trained model reached high accuracy for open flower detection, which allowed to monitor flowering dynamics and flower density over time. Maximal flower density (Max.Fl.Dens) was highly correlated (R2= 0.967) to ground truth data taken in the field. Clear differences in timing of flowering and flower density were detected between breeding lines and years. Furthermore, a high correlation was observed between the maximal flower density and yield components. This automated, data-driven method of flower and pod detection proved itself as a reliable tool. Therefore, the results are promising for the use of RGB imaging methods to objectively assess not only flowering dynamics but also flower density and fruiting efficiency. Maximal flower density allows to predict seed amount and therefore has potential as selection trait in breeding programs. Fruiting efficiency could be used to identify stress-tolerant breeding lines.
The genetic basis of apple shape and size unraveled by digital phenotyping
Keller, Beat; Jung, Michaela; Bühlmann-Schütz, Simone; et al. (2024)
G3: Genes, Genomes, Genetics
Great diversity of shape, size, and skin color is observed among the fruits of different apple genotypes. These traits are critical for consumers and therefore interesting targets for breeding new apple varieties. However, they are difficult to phenotype and their genetic basis, especially for fruit shape and ground color, is largely unknown. We used the FruitPhenoBox to digitally phenotype 525 genotypes of the apple reference population (apple REFPOP) genotyped for 303,148 single nucleotide polymorphism (SNP) markers. From the apple images, 573 highly heritable features describing fruit shape and size as well as 17 highly heritable features for fruit skin color were extracted to explore genotype-phenotype relationships. Out of these features, seven principal components (PCs) and 16 features with the Pearson's correlation r < 0.75 (selected features) were chosen to carry out genome-wide association studies (GWAS) for fruit shape and size. Four PCs and eight selected features were used in GWAS for fruit skin color. In total, 69 SNPs scattered over all 17 apple chromosomes were significantly associated with round, conical, cylindrical, or symmetric fruit shapes and fruit size. Novel associations with major effect on round or conical fruit shapes and fruit size were identified on chromosomes 1 and 2. Additionally, 16 SNPs associated with PCs and selected features related to red overcolor as well as green and yellow ground color were found on eight chromosomes. The identified associations can be used to advance marker-assisted selection in apple fruit breeding to systematically select for desired fruit appearance.

Publications 1 - 10 of 12

Beat Keller

Last Name

First Name

ORCID

Organisational unit

Filters

Search Results