Legumes crops are important for sustainable agriculture and global food security. Among them white lupin (Lupinus albus L.), is characterized by exceptional protein content of high nutritional value, competitive to that of soybean (Glycine max) and is well adapted to rainfed agriculture. However, its high seed-quinolizidine alkaloid (QA) content impedes its direct integration to human diet and animal feed. Additionally, its cultivation is not yet intensive, remains confined to local communities and marginal lands in Mediterranean agriculture, while adaptation to local microclimates restrains its cultivation from expanding globally. Hence, modern white lupin breeding aims to exploit genetic resources for the development of “sweet” elite cultivars, resilient to biotic adversities and well adapted for cultivation on a global level. Towards this aim, we evaluated white lupin local landrace germplasm from Greece, since the country is considered a center of white lupin diversity, along with cultivars and breeding lines for comparison. Seed morphological diversity and molecular genetic relationships were investigated. Most of the landraces were distinct from cultivars, indicating the uniqueness of their genetic make-up. The presence of pauper “sweet” marker allele linked to low seed QA content in some varieties was detected in one landrace, two breeding lines, and the cultivars. However, QA content in the examined genotypes did not relate with the marker profile, indicating that the marker’s predictive power is limited in this material. Marker alleles for vernalization unresponsiveness were detected in eight landraces and alleles for anthracnose resistance were found in two landraces, pointing to the presence of promising germplasm for utilization in white lupin breeding. The rich lupin local germplasm genetic diversity and the distinct genotypic composition compared to elite cultivars, highlights its potential use as a source of important agronomic traits to support current breeding efforts and assist its integration to modern sustainable agriculture.

Selenium adsorption/desorption behavior was examined for eight Greek top soils with different properties, aiming to describe the geochemistry of the elements in the selected soils in terms of bioavailability and contamination risk by leaching. Four soils were acid and four alkaline, and metal oxides content greatly differed between the two groups of soils. The concentrations of Se(IV) used for the performed adsorption batch experiments ranged from 1 to 50 mg/L, while the soil to solution ratio was 1 g/0.03 L. Acid soils adsorbed significantly higher amounts of the added Se(IV) than alkaline soils. Freundlich and Langmuir equations adequately described the adsorption of Se(IV) in the studied soils, and the parameters of both isotherms significantly correlated with soil properties. In particular, both KF and qm values significantly positively correlated with ammonium oxalate extractable Fe and with dithionite extractable Al and Mn, suggesting that amorphous Fe oxides and Al and Mn oxides greatly affect exogenous Se(IV) adsorption in the eight soils. These two parameters were also significantly negatively correlated with soil electrical conductivity (EC) values, indicating that increased soluble salts concentration suppresses Se(IV) adsorption. No significant relation between adsorbed Se(IV) and soil organic content was recorded. A weak salt (0.25 M KCl) was used at the same soil to solution ratio to extract the amount of the adsorbed Se(IV) that is easily exchangeable and thus highly available in the soil ecosystem. A much higher Se(IV) desorption from alkaline soils was observed, pointing to the stronger retention of added Se(IV) by the acid soils. This result implies that in acid soils surface complexes on metal oxides may have been formed restricting Se desorption.

Selenium biofortification of lettuce plants was studied for two rates (5 and 10 mg kg−1 soil) of either selenate or selenite and for the effect of 5% w/w biochar addition. Lettuce seedlings were grown in pots containing 1 kg of a calcareous soil. Twelve weeks later, the plants were harvested and selenium (Se), phosphorus (P), and sulfur (S) concentrations were determined in heads and roots. Plant growth characteristics were measured and plant biometrics were assessed by NDVI, NDRE, and SPAD measurements. The highest Se concentration of 315.19 mg kg−1 D.W. and the highest amount of Se taken up by plants (950.5 μg/pot) were observed for the low selenate rate with biochar. The corresponding values for selenite treatments were an order of magnitude lower. Although in general, minor to severe toxicity symptoms occurred with selenium application in no biochar treatments (except selenite low rate), the addition of biochar secured plant growth and increased S and P concentrations in plants, regulating Se uptake by plants at high selenite rate and allowing maximum plant uptake at the low selenate rate. To propose an appropriate Se fertilization rate, the fate of excess selenates in the soil environment should be examined and experimentation under soil conditions is necessary.

The Philippi peatland is considered the biggest peat deposit in the Balkan Peninsula and one of the deepest in the world. The purpose of this study was to access the impact of eight potentially toxic elements (PTEs), i.e., As, Se, Pb, Cr, Ni, Zn, Mn and Cu, on the local environment. PTE content was determined in corn grains and surface soil samples collected from 16 sites in the peatland, and pollution indices were calculated to evaluate the environmental risks. Soil organic matter ranged between 93 and 557 g kg−1 soil, whereas the soil pH was >7, classifying the soils as neutral to slightly alkaline. Mean PTE contents in soil samples were 24.6 mg kg−1 soil for As, 1.68 mg kg−1 soil for Se, 113 mg kg−1 soil for Pb, 32 mg kg−1 soil for Cr, 36.3 mg kg−1 soil for Ni, 141.4 mg kg−1 soil for Zn, 35.5 mg kg−1 soil for Cu and 845 mg kg−1 soil for Mn. In corn grain samples, 0.06 mg kg−1 grain for As, 0.14 mg kg−1 grain for Se, 1.34 mg kg−1 grain for Cr, 0.69 mg kg−1 grain for Ni, 27 for Zn, 8.4 mg kg−1 grain for Cu and 3.2 mg kg−1 grain for Mn were recorded. No Pb was detected in the corn grains. The bioaccumulation factor (BF) was high for Cu, Zn and Se, indicating increased mobility of these elements in the soils and preferential plant uptake. For most soil samples, the geoaccumulation index (Igeo) and single pollution index (PI) showed low to moderate contamination. However, Igeo and PI values of Se in many sampling sites and of Pb and Zn in few were substantially increased, pointing to heavily contaminated soils. According to potential ecological risk (RI), the PTE content in the peat soils of Philippi imposes low to moderate risk on the environment.

Cowpea is a nutrient-rich staple legume and climate-resilient crop for vulnerable agroecosystems. However, the crop still remains underutilized, mainly due to its narrow genetic base, and the production is often ravaged by aphid infestation outbreaks. Thus, genetic diversity assessment and the detection of defense-related alleles are fundamental to germplasm management and utilization in breeding strategies to support food safety in climate change times. A germplasm collection of 87 cowpea landraces sourced from Greece was subjected to seed phenotyping, SSR genotyping and to screening for the presence of aphid-resistance-conferring alleles. Significant diversity in the species’ local germplasm was revealed. The landraces were grouped in metapopulations based on their broader geographical origin. High amounts of variation and statistically significant differences were detected among the landraces regarding the seed morphological traits, the seed color and eye color according to MANOVA (Wilk’s λ = 0.2, p < 0.01) and significant correlations were revealed among these features according to Pearson’s test (p < 0.05). High levels of genetic polymorphism were detected for the metapopulations, ranging from 59% (VuPop3) to 82% (VuPop4). The AMOVA revealed that 93% of the molecular diversity was distributed among the landraces of each metapopulation. Further population structure analysis presumed the existence of two inferred populations, where in population A, 79% of the landraces have a cream/cream-brown seed coat, whereas in population B, 94% of the landraces are brown-ochre to black-seeded. Molecular screening for alleles conferring aphid resistance revealed the correspondence of 12 landraces to the resistant genotype of TVu-2876. The study highlights the importance of cowpea germplasm collection genetic diversity, as a source of important agronomic traits, to support breeding efforts and expand cowpea cultivation to foster food security and agriculture sustainability and diversification in climate change.