Global analysis of Coffea canephora Pierre ex Froehner (Rubiaceae) from the Guineo-Congolese region reveals impacts from climatic refuges and migration effects

As the second species used for commercial coffee, evaluation of Coffea canephora Pierre ex Froehner population genetics is a challenging task for coffee breeding. This study examined the pattern of genetic variability and genetic relationships of cultivated and wild populations of C. canephora sampled across the Guineo-Congolese region of Africa and some improved populations maintained in field genebanks. A total of 293 individuals, sampled from 17 populations, were genotyped with 39 nuclear microsatellite markers. Genetic diversity and structure were investigated with both a model-based and a graphical approach; isolation by distance was also tested. Relationships between the diversity clusters are discussed with regard to differentiation due to several glacial refuges during the Last Glacial Maximum (LGM). High genetic diversity within C. canephora is confirmed with a mean number of alleles of 11.85 per marker, a mean gene diversity of 0.72 and a mean observed heterozygosity of 0.36. An overall structure of two main groups (Guinean and Congolese) subdivided in six subgroups (2 for the Guinean and 4 for the Congolese) was found, including one described for the first time in the Guinean group. A fine structure within the Guinean group was also newly detected. Genetic structure of C. canephora appears to be consistent with its geographic repartition at the continent scale. Structure of diversity was found in accordance with localizations of refuge zones during LGM and migration from this period. Results from this genetic structure study raise our capabilities to better manage and use the collections of genetics resources for breeding purposes. Those results will be used in future association studies to optimize the number of genotypes to be phenotyped.     

Biofortification of soybean grains with foliar application of Li sources

Abstract

Biofortification of soybean grains with lithium (Li) is a strategy to improve a food with high social acceptance, in order to promote health benefits. The aim of this work was to evaluate the development of plants and the production of biofortified soybeans with two Li sources. The experiment was conducted in a completely randomized design with five replicates. Ten treatments were obtained in a 2x5 factorial scheme, comprising two sources of Li (LiOH - Li hydroxide and Li₂SO₄ - Li sulfate) and five doses (0, 30, 60, 90 and 120?mg kg^?1) in stages V4 and R1. The supply of Li promoted significant effects (p?≤?0.05) on the morphology, yield components and nutritional status of soybean plants. The highest grain yield was obtained with the use of Li₂SO₄ at the estimated dose of 45.7?mg kg^?1. The plants accumulated Li between 8.00 and 11.20?mg kg ^?1, respectively, with the use of Li₂SO₄ and LiOH. In the grains, the highest concentrations of Li were obtained with the application of 120?mg kg^?1. Li₂SO₄ and LiOH are good sources for biofortification of soybean grains.     

Using Limestone to Improve Soil Fertility and Growth of Mango (Mangifera Indica L.)

Soil acidity is one of the most important factors limiting crop production. The objective of this work was to evaluate the effects of limestone application on the soil chemical properties, nutrition and yield of mango plants in an orchard under implementation. The design was randomized blocks, with five limestone doses (0; 2; 4; 6 and 8 t ha^?1) and four replications. Soil chemical analyses were performed (at 12, 24, 36 and 48 months after the experiment implementation) in the layers 0–20; 20–40 and 40–60 cm deep. Nutrition status and yield were assessed during the first and second crop seasons. The highest fruit yield was associated with the application of 3.9 and 3.8 t ha^?1 of limestone in the 2008/09 and 2009/10 seasons, respectively, that is, the dose recommended by the literature for raising base saturation to 80%, as a function of the fertility conditions of the soil initially obtained.     

Uncertainty assessment of soya bean yield gaps using DSSAT‐CSM‐CROPGRO‐Soybean calibrated by cultivar maturity groups

Soya bean yield gap can be caused by different factors resulting in uncertainties when the objective is to use such information for farm decision‐making and reference yield determination. Thus, this study aimed to quantify the soya bean yield gap for four sites, located in Southern and Midwestern Brazil, as well as the uncertainties of that related to cultivars, sowing dates, soil types and reference yields. The crop simulation model DSSAT‐CSM‐CROPGRO‐Soybean was calibrated for cultivars with similar maturity groups, based on the data obtained from the best farmers at the county level. The yield gap by water deficit (YG_WD) was obtained through the difference between potential and attainable yields, and that one caused by sub‐optimum crop management (YG_CM) by subtracting actual yield of each county, obtained from official statistics between 1989/90 and 2014/15 growing seasons, from the estimated attainable yield. The yield was simulated using four sowing dates, three soil types and two soya bean maturity groups by county. The reference yield uncertainty was quantified using yield reference from crop model and regional winners of the soya bean yield context, conducted by CESB (Brazilian Soybean Strategic Committee), for the growing seasons from 2013/14 to 2015/16. The crop model showed a good agreement between measured and simulated crop development and growth using calibration by maturity group, with low root mean square error (347 kg/ha). Southern sites had a mean YG_WD of 1,047 kg/ha, while in the Midwest, it was lower than 100 kg/ha. The YG_CM was 1,067, 528, 984 and 848 kg/ha, respectively, for Castro, PR, Mamborê, PR, Montividiu, GO and Primavera do Leste, MT, representing the opportunity for yield gain when having the best farmers as reference. The maturity groups, sowing dates and soil types showed to be an important source of uncertainty for yield gap determination, being recommended to investigate the farms in detail for an appropriate quantification. The reference yield showed expressive uncertainties, with some farmers presenting conditions to increase their soya bean yields by more than 3,000 kg/ha, when considering as reference the yields obtained by the winners’ farmers. These results show that uncertainties must be reduced when assessing farm yield gaps, in order to ensure that expected rate of soya bean yield growth could be reached by adopting the same technologies from CESB winners and best farmers in the county as a reference.     

Contents of carboxylic acids and two phenolics and antioxidant activity of dried portuguese wild edible mushrooms

The organic acids and phenolics compositions of nine wild edible mushrooms species (Suillus bellini, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Suillus luteus, and Suillus granulatus) were determined by HPLC-UV and HPLC-DAD, respectively. The antioxidant potential of these species was also assessed by using the DPPH* scavenging assay. The results showed that all of the species presented a profile composed of at least five organic acids: oxalic, citric, malic, quinic, and fumaric acids. In a general way, the pair of malic plus quinic acids were the major compounds. Only very small amounts of two phenolic compounds were found in some of the analyzed species: p-hydroxybenzoic acid (in A. rubescens, R. cyanoxantha, and T. equestre) and quercetin (in S. luteus and S. granulatus). All of the species exhibited a concentration-dependent scavenging ability against DPPH*. T. rutilans revealed the highest antioxidant capacity.     

A novel vasodilatory peptide from the salivary glands of the sand fly Lutzomyia longipalpis

Salivary gland lysates of the sand fly Lutzomyia longipalpis contain a potent vasodilator that aids the fly to feed on the blood of its vertebrate hosts. Chromatographic analysis, antibody reactivity, and data obtained from bioassays of the salivary erythema-inducing factor indicate striking similarity with human calcitonin gene-related peptide. The erythema-inducing factor is, however, at least one order of magnitude more potent than calcitonin gene-related peptide.     

Field validation of chlordecone soil sequestration by organic matter addition

Purpose

The use of chlordecone (CLD) has caused pollution of soils, which are now a source of contamination for crops and ecosystems. Because of its long-term impacts on human health, exposure to CLD is a public health concern and contamination of crops by CLD must be limited. To this end, we conducted field trials on chlordecone sequestration in soil with added compost.

Materials and methods

The impact of added compost on chlordecone sequestration was measured in nitisols. After characterization of the soil, the transfer of chlordecone from soil to water was assessed in a leaching experiment and from soil to two crop plants in a nitisol plot. Finally, to understand the underlying processes, changes in CLD content were measured in soil fractions and soil porous properties were assessed after the addition of compost.

Results and discussion

A rapid seven-fold decrease in water extractable CLD was observed in amended soils. Five percent amendment led to a significant reduction in the contamination of crops by CLD; edible radish tubers were 50% more contaminated without added compost and cucumber fruits were 60% more contaminated. After the addition of compost, CLD content increased in the fraction of pre-humified or partially mineralized organic debris. Finally, in contrast to andosols, adding compost to nitisols did not affect the soil microstructure.

Conclusions

Increasing chlordecone sequestration by adding compost could be an alternative solution until soil decontamination techniques become available. This could be a provisional way to control further release of CLD from contaminated soils towards other environmental compartments.