We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions.

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Stem biomechanical properties dictate the mechanical stability of crop plants and ultimately their lodging resistance. This study evaluated stem mechanical, morphological, anatomical, and composition traits to assess their association with historical lodging ratings and developed new approaches to predict stem strength. Significant genotypic variation for stem strength, rigidity, and stiffness existed among 15 bioenergy Sorghum bicolor (L.) Moench genotypes that were selected to represent a range of stem lodging tendencies. Repeatabilities for the mechanical traits ranged from moderate to high across environments (0.58–0.92), high within environments (0.81–0.89), and low to high for maturity groups (0.31–0.89). Lodging rating was moderately correlated with internode density (r = 0.60, P < 0.01), length (r = 0.61, P < 0.01), and rigidity (r = 0.60, P < 0.05). Mechanical traits were highly correlated with morphological traits; correlations with anatomical or composition traits were lower. Using this information, two predictive models were developed. In Model 1, stiffness explained 69% of the total variation for stem strength. In Model 2, a combination of internode density, volume, and stiffness explained 75% of the total variation. Both prediction models were robust and were not confounded by internode number, cultivar type, maturity group, or environment. The results indicate that indirect selection of lodging‐related traits may be possible with the specific use of stiffness as a selective breeding tool to improve lodging resistance.

BackgroundIn bioenergy/forage sorghum, morpho-anatomical stem properties are major components affecting standability and juice yield. However, phenotyping these traits is low-throughput, and has been restricted by the lack of a high-throughput phenotyping platforms that can collect both morphological and anatomical stem properties. X-ray computed tomography (CT) offers a potential solution, but studies using this technology in plants have evaluated limited numbers of genotypes with limited throughput. Here we suggest that using a medical CT might overcome sample size limitations when higher resolution is not needed. Thus, the aim of this study was to develop a practical high-throughput phenotyping and image data processing pipeline that extracts stem morpho-anatomical traits faster, more efficiently and on a larger number of samples.ResultsA medical CT was used to image morpho-anatomical stem properties in sorghum. The platform and image analysis pipeline revealed extensive phenotypic variation for important morpho-anatomical traits in well-characterized sorghum genotypes at suitable repeatability rates. CT estimates were highly predictive of morphological traits and moderately predictive of anatomical traits. The image analysis pipeline also identified genotypes with superior morpho-anatomical traits that were consistent with ground-truth based classification in previous studies. In addition, stem cross section intensity measured by the CT was highly correlated with stem dry-weight density, and can potentially serve as a high-throughput approach to measure stem density in grass stems.ConclusionsThe use of CT on a diverse set of sorghum genotypes with a defined platform and image analysis pipeline was effective at predicting traits such as stem length, diameter, and pithiness ratio at the internode level. High-throughput phenotyping of stem traits using CT appears to be useful and feasible for use in an applied breeding program.Electronic supplementary materialThe online version of this article (10.1186/s13007-018-0326-3) contains supplementary material, which is available to authorized users.

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The importance of legumes in sustainable cropping systems has been studied extensively. Among legumes, common beans (Phaseolus vulgaris L.) are a rich world resource of biodiversity with two centers of domestication (Andes and Central America) and over 10 major market classes cultivated globally. Common beans are recognized as a nutrient-dense, healthy food source due to their high protein, dietary fiber, and minerals content and also being a rich source of resistant and slowly digestible starch, which elicits a lower glycemic response. Some bioactive compounds present in beans are reported to mitigate cardiovascular diseases, hypertension, hyper-cholesterolemia, and cancer. Dry bean production systems provide unique advantages that support sustainability, including a low carbon footprint and short growth cycle, which facilitates crop diversification and cover crop integration. Symbiotic nitrogen fixation (SNF), a unique characteristic of legumes, promotes environmentally friendly production through modest fertilizer use. Advances to improve the upright plant architecture of beans during the last two decades have enhanced options for direct harvest thereby reducing the number of equipment passes required. Overall, the sustainability implications of diversifying crop rotation using beans result in reduced requirements for environmentally unfriendly inputs and buffering of crop productivity under variable weather conditions. This review article covers common beans' role in agricultural sustainability (biodiversity, SNF, rotational diversity, harvest management) and as a sustainable source of nutrition and food security. Further discussion includes measures to enhance dry beans sustainability through breeding and crop management practices by addressing biotic and abiotic stresses (diseases, drought, high temperature, waterlogging, conservation tillage).

Sorghum bicolor (L.) Moench is the fifth most commonly grown cereal crop worldwide with unrivaled drought tolerance compared with other cereal crops. Drought and heat tolerance and high biomass yield potential make sorghum a promising bioenergy crop. However, stem lodging is a significant problem that results in substantial yield losses. Stem biomechanical traits influence the mechanical stability of crops and breeding for desirable biomechanical traits may result in improved lodging resistance. In this study, we report the identification of quantitative trait loci (QTL) for stem mechanical and morphological traits in three recombinant inbred line (RIL; populations from Tx623/Rio, Tx623/Della, and Tx631/Della) crosses between elite grain and sweet sorghum parents. The genetic architecture of stem biomechanical traits in the three RIL populations is multigenic and pleiotropic. Eight QTL affecting mechanical and morphological traits were detected; two main effects of these QTL were consistently found in all populations and colocated with previously identified dwarfing genes Dw1 and Dw3. These results indicate that dwarfing genes affect the mechanical properties of sorghum stems and their lodging resistance, while also having demonstrable effects on stem morphology. The identification of these QTL provides new opportunities for improving stem lodging resistance via genomics‐assisted breeding.

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