Crop adaptation to climate change as a consequence of long-term breeding

Major global crops in high-yielding, temperate cropping regions are facing increasing threats from the impact of climate change, particularly from drought and heat at critical developmental timepoints during the crop lifecycle. Research to address this concern is frequently focused on attempts to identify exotic genetic diversity showing pronounced stress tolerance or avoidance, to elucidate and introgress the responsible genetic factors or to discover underlying genes as a basis for targeted genetic modification. Although such approaches are occasionally successful in imparting a positive effect on performance in specific stress environments, for example through modulation of root depth, major-gene modifications of plant architecture or function tend to be highly context-dependent. In contrast, long-term genetic gain through conventional breeding has incrementally increased yields of modern crops through accumulation of beneficial, small-effect variants which also confer yield stability via stress adaptation. Here we reflect on retrospective breeding progress in major crops and the impact of long-term, conventional breeding on climate adaptation and yield stability under abiotic stress constraints. Looking forward, we outline how new approaches might complement conventional breeding to maintain and accelerate breeding progress, despite the challenges of climate change, as a prerequisite to sustainable future crop productivity.Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347Justus-Liebig-Universität Gießen (3114)Peer Reviewe

The Economic Impact of Exchanging Breeding Material: Assessing Winter Wheat Production in Germany

Climate change impacts imply that the stabilization and improvement of agricultural production systems using technological innovations has become vital. Improvements in plant breeding are integral to such innovations. In the context of German crop breeding programs, the economic impact of exchanging genetic material has yet to be determined. To this end, we analyze in this impact assessment the economic effects on German winter wheat production that are attributable to exchanging parental material amongst breeders in the breeding process. This exchange is supported by the breeders’ exemption, which is an integral part of the German plant variety protection legislation. It ensures that breeders can freely use licensed varieties created by other breeders for their own breeding activities and aims to speed up the development of improved varieties. For our analysis, we created a unique data set that combines variety-specific grain yield, adoption, and pedigree information of 133 winter wheat varieties. We determined the parental pedigree of each variety to see if a variety was created by interbreeding varieties that are internal or external to its specific breeder. Our study is the first that analyzes the economic impact of exchanging genetic material in German breeding programs. We found that more than 90 % of the tested varieties were bred with exchanged parental material, whereby the majority had two external parents. Also, these varieties were planted on an 8.5 times larger area than the varieties that were bred with two internal parents. Due to lower adoption, these only contributed 11 % to the overall winter wheat production in Germany, even though they yielded more. We used an economic surplus model to measure the benefits of exchanging parental breeding material on German winter wheat production. This resulted in an overall estimated economic surplus of 19.2 to 22.0 billion EUR from production year 1972 to 2018. This implies tremendous returns to using the breeder’s exemption, which, from an economic perspective, is almost cost-free for the breeder. We conclude that the exchange of breeding material contributes to improving Germany’s agricultural production and fosters the development of climate-resilient production systems and global food security. © Copyright © 2020 Lüttringhaus, Gornott, Wittkop, Noleppa and Lotze-Campen

The Economic Impact of Exchanging Breeding Material: Assessing Winter Wheat Production in Germany

Climate change impacts imply that the stabilization and improvement of agricultural production systems using technological innovations has become vital. Improvements in plant breeding are integral to such innovations. In the context of German crop breeding programs, the economic impact of exchanging genetic material has yet to be determined. To this end, we analyze in this impact assessment the economic effects on German winter wheat production that are attributable to exchanging parental material amongst breeders in the breeding process. This exchange is supported by the breeders’ exemption, which is an integral part of the German plant variety protection legislation. It ensures that breeders can freely use licensed varieties created by other breeders for their own breeding activities and aims to speed up the development of improved varieties. For our analysis, we created a unique data set that combines variety-specific grain yield, adoption, and pedigree information of 133 winter wheat varieties. We determined the parental pedigree of each variety to see if a variety was created by interbreeding varieties that are internal or external to its specific breeder. Our study is the first that analyzes the economic impact of exchanging genetic material in German breeding programs. We found that more than 90 % of the tested varieties were bred with exchanged parental material, whereby the majority had two external parents. Also, these varieties were planted on an 8.5 times larger area than the varieties that were bred with two internal parents. Due to lower adoption, these only contributed 11 % to the overall winter wheat production in Germany, even though they yielded more. We used an economic surplus model to measure the benefits of exchanging parental breeding material on German winter wheat production. This resulted in an overall estimated economic surplus of 19.2 to 22.0 billion EUR from production year 1972 to 2018. This implies tremendous returns to using the breeder’s exemption, which, from an economic perspective, is almost cost-free for the breeder. We conclude that the exchange of breeding material contributes to improving Germany’s agricultural production and fosters the development of climate-resilient production systems and global food security.Peer Reviewe

QUANTITATIVE GENETIC ANALYSIS OF PHENOLIC ACIDS IN OILSEED RAPE MEAL

Rapeseed meal, a by-product of oilseed extraction related to the agri-food and biofuel industries due to its favourable composition of essential amino acids, is currently utilised for animal feed. In this study, 166 doubled haploid (DH) rapeseed lines from the segregating Brassica napus doubled haploid population YE2-DH were genetically and chemically analysed for phenolic acids. The relationship between seed colour and phenolic acid fractions in B. napuswas investigated using these analyses to improve the quality of rapeseed meal. High-performance liquid chromatography assays were used to estimate phenolic acid content, and the outcomes were used to identify quantitative trait loci (QTL). Nine quantitative feature loci for three distinct phenolic acid compounds were mapped to seven linkage groups. A minor QTL for sinapine was located on linkage group C05 in the same interval as the QTL for seed colour. On chromosome A09, two loci for phenolic acids colocalised with the main QTL for seed colour. Closely linked molecular markers for the target traits (seed colour, phenolic acids) identified during this study could be useful tools for breeding new oilseed rape cultivars with lower levels of antinutritive compounds

Quantitative genetic analysis of phenolic acids in oilseed rape meal

Rapeseed meal, a by-product of oilseed extraction related to the agri-food and biofuel industries due to its favourable composition of essential amino acids, is currently utilised for animal feed. In this study, 166 doubled haploid (DH) rapeseed lines from the segregating Brassica napus doubled haploid population YE2-DH were genetically and chemically analysed for phenolic acids. The relationship between seed colour and phenolic acid fractions in B. napuswas investigated using these analyses to improve the quality of rapeseed meal. High-performance liquid chromatography assays were used to estimate phenolic acid content, and the outcomes were used to identify quantitative trait loci (QTL). Nine quantitative feature loci for three distinct phenolic acid compounds were mapped to seven linkage groups. A minor QTL for sinapine was located on linkage group C05 in the same interval as the QTL for seed colour. On chromosome A09, two loci for phenolic acids colocalised with the main QTL for seed colour. Closely linked molecular markers for the target traits (seed colour, phenolic acids) identified during this study could be useful tools for breeding new oilseed rape cultivars with lower levels of antinutritive compounds

Sustained virological response after treatment with direct antiviral agents in individuals with HIV and hepatitis C co-infection.

INTRODUCTION Randomized trials and observational studies have consistently reported rates of sustained virological response (SVR), equivalent to hepatitis C virus (HCV) cure, as high as 95% following treatment with direct-acting antiviral (DAA) treatment in individuals with HIV and HCV co-infection. However, large studies assessing whether SVR rates differ according to demographic and clinical strata are lacking. Additionally, the SVR rates reported in the literature were typically computed in non-random samples of individuals with available post-DAA HCV-RNA measures. Here, we aimed to estimate the probability of SVR after DAA treatment initiation in persons with HIV and HCV co-infection overall and by demographic and clinical characteristics with and without adjustment for missing HCV-RNA testing. METHODS We included adults with HIV-HCV co-infection who received DAA treatment between 2014 and 2020 in HepCAUSAL, an international collaboration of cohorts from Europe and North America. We estimated the proportions of DAA recipients who had documented SVR (defined as an undetectable HCV-RNA at least 12 weeks after the end of DAA treatment) overall and by strata defined by age, sex, presence of cirrhosis, calendar period, mode of HIV acquisition, CD4 cell count and HCV genotype at DAA treatment. We then compared these rates with those obtained using the parametric g-formula to impute SVR status for individuals with no SVR assessment. RESULTS AND DISCUSSION A total of 4527 individuals who initiated DAA treatment (88% males, median [IQR] age 56 [50, 62] years) were included. Of the total of 642 (14%) individuals had no HCV-RNA test on or after 12 weeks after the end of treatment. The overall observed and g-formula imputed SVR rates were 93% (95% CI 93, 94) and 94% (95% CI 92, 95), respectively. SVR estimates were similarly high across all strata. A substantial proportion of individuals who received DAA treatment were never assessed for SVR post-DAA and strategies for more systematic routine HCV-RNA testing should be considered. CONCLUSIONS Our estimates with and without adjustment for missing HCV-RNA testing indicate SVR rates of approximately 95%, like those reported in clinical trials

Meta-analysis reveals that pollinator functional diversity and abundance enhance crop pollination and yield

How insects promote crop pollination remains poorly understood in terms of the contribution of functional trait differences between species. We used meta-analyses to test for correlations between community abundance, species richness and functional trait metrics with oilseed rape yield, a globally important crop. While overall abundance is consistently important in predicting yield, functional divergence between species traits also showed a positive correlation. This result supports the complementarity hypothesis that pollination function is maintained by non-overlapping trait distributions. In artificially constructed communities (mesocosms), species richness is positively correlated with yield, although this effect is not seen under field conditions. As traits of the dominant species do not predict yield above that attributed to the effect of abundance alone, we find no evidence in support of the mass ratio hypothesis. Management practices increasing not just pollinator abundance, but also functional divergence, could benefit oilseed rape agriculture

Resistance Breeding Increases Winter Wheat Gross Margins

Improved wheat varieties have ameliorated our food production. Intensive cropping systems, as in Germany, achieve very high grain yields and thus contribute greatly to global food security. As diseases, especially fungal pathogens, pose major threats in winter wheat production, disease management is crucial to uphold high production levels and to avoid economic losses. Yet, the economic value of breeding varieties with increased resistance to fungal pathogens has not been analyzed with comprehensive data. Our analysis fills this gap by quantifying the economic effects of 50 years of resistance breeding for winter wheat production in Germany. Based on field trials and agronomic production data, we analyze how resistances have influenced the economic profitability of the crops. Thereby, we can isolate the pure breeding-induced effects of increased resistance to fungal pathogens, which cause leaf and stripe rust, powdery mildew, and Fusarium head blight. We calculated the gross margins of 176 varieties according to nitrogen and fungicide applications in field trials. Regression models show that resistance breeding had a strong positive and statistically significant effect on the gross margins of the varieties. In comparison, the specific meta-environment of the season had a larger effect, while the effect of high nitrogen as well as fungicide treatments was lower. The gross margin increased over time along with higher resistances. Simultaneously, the difference in gross margins between the fungicide-treated and untreated variants decreased, indicating an increased contribution of resistances to yield stability. Resistances have increased gross margins greatly, as the health levels of varieties remain high without the need for fungicide applications and thus production costs can be saved. We conclude that resistance breeding has increased the economic profitability and sustainability of crop production due to a reduction in the costs for fungicides. In fields of farmers, these positive effects of resistance breeding can be fully realized by an optimal variety choice and a variety- and situation-specific disease management. Such an agronomic practice would not only further improve winter wheat gross margins but also mitigate some of the pressures on agricultural productions, such as reduced disease management options and adverse climate change impacts.Peer Reviewe

Heterosis for biomass and grain yield facilitates breeding of productive dual-purpose winter barley hybrids

Winter barley (Hordeum vulgare L.) can be a valuable supplement as whole plant silage for bioenergy production due to positive effects of plant cover over winter and the possibility of growing a subsequent second crop after barley. However, to be competitive with other bioenergy crops, barley dry matter yield (DMY) needs to be enhanced. Therefore, we tested a factorial of 96 barley experimental hybrids together with their parental lines for DMY, grain yield (GY), and yield-associated traits in a multi-environmental field plot trial with a practical focus. The average best-parent heterosis (BPH) of GY was 7.7%, whereas average BPH of DMY was 9.1%. The higher GY of hybrids was mainly caused by the higher kernel number per ear. The variance of specific combining ability (SCA) was higher than that of general combining ability (GCA), revealing prevalence of non-additive effects on barley DMY. Additionally, SCA values highly correlated with those of DMY and GY (r = 0.752 and r = 0.839, respectively), as well as with values of mid-parent heterosis (MPH; r = 0.768 [DMY], r = 0.877 [GY]) and BPH (r = 0.695 [DMY], r = 0.768 [GY]). There was a correlation between the parental genetic distance and hybrid DMY, whereas no correlations were found between the parental per se and hybrid DMY and GY values. These results suggest that future hybrid breeding should be run in a separate program with a main focus on the establishment of heterotic pools and an increase in genetic diversity

Mapping-by-sequencing reveals genomic regions associated with seed quality parameters in <em>Brassica napus</em>

Schilbert H, Pucker B, Ries D, et al. Mapping-by-sequencing reveals genomic regions associated with seed quality parameters in &lt;em&gt;Brassica napus&lt;/em&gt;. Genes. 2022;13(7): 1131.Rapeseed (Brassica napusL.) is an important oil crop and harbours the potential to serve as a highly productive source of protein. This protein exhibits an excellent amino acid composition and has a high nutritional value for humans. Seed protein content (SPC) and seed oil content (SOC) are two complex quantitative and polygenic traits which are negatively correlated and assumed to be controlled by additive and epistatic effects. A reduction of seed glucosinolate (GSL) content is desired as GSLs cause a stringent and bitter taste. The goal here was the identification of genomic intervals relevant for seed GSL content and SPC/SOC. Mapping-by-sequencing (MBS) revealed 30 and 15 new and known genomic intervals associated with seed GSL content and SPC/SOC, respectively. Within these intervals we identified known but also so far unknown putatively causal genes and sequence variants. A 4 bp insertion in theMYB28homolog on C09 shows a significant correlation with a reduction in seed GSL content. This study provides insights into the genetic architecture and potential mechanisms underlying seed quality traits, which will enhance future breeding approaches inB. napus