Root traits of European Vicia faba cultivars-Using machine learning to explore adaptations to agroclimatic conditions

High-Throughput Phenotyping Methods for Breeding Drought-Tolerant Crops

Drought is a main factor limiting crop yields. Modern agricultural technologies such as irrigation systems, ground mulching, and rainwater storage can prevent drought, but these are only temporary solutions. Understanding the physiological, biochemical, and molecular reactions of plants to drought stress is therefore urgent. The recent rapid development of genomics tools has led to an increasing interest in phenomics, i.e., the study of phenotypic plant traits. Among phenomic strategies, high-throughput phenotyping (HTP) is attracting increasing attention as a way to address the bottlenecks of genomic and phenomic studies. HTP provides researchers a non-destructive and non-invasive method yet accurate in analyzing large-scale phenotypic data. This review describes plant responses to drought stress and introduces HTP methods that can detect changes in plant phenotypes in response to drought.

Differences in Grain Microstructure and Proteomics of a Broad Bean (Vicia faba L.) Landrace Cixidabaican in China Compared with Lingxiyicun Introduced from Japan

In response to the germplasm resources' conservation in China, the characters of a superior landrace of broad bean (Vicia faba L.) Cixidabaican (CX) were identified, compared with Lixiyicun (LX) introduced from Japan. The plant morphology and root structure of CX were larger, pods/seeds number and yield per plant were higher, but the size of pods/seeds and single-seed weight were lower than the similar characteristics in LX. The protein content of dry seeds of CX was 4.1% lower than LX, while the amino acids contents showed no difference between the two cultivars. The seed scan electron micrograph showed that the structure of starch granules was similar, while the granules number was lower in CX than LX. iTRAQ-based proteomics showed that 80 differentially abundant proteins (DAPs) were higher, and 45 DAPs were less abundant in the seeds of CX compared to LX, and DAPs were enriched in proteins of carbohydrate and amino acid metabolism. These results verified the importance of the further study of landraces by showing superior traits of CX, which could contribute to the breeding of better-quality varieties.

Association of Shoot and Root Responses to Water Deficit in Young Faba Bean (Vicia faba L.) Plants

Water deficit may occur at any stage of plant growth, with any intensity and duration. Phenotypic acclimation and the mechanism of adaptation vary with the evolutionary background of germplasm accessions and their stage of growth. Faba bean is considered sensitive to various kinds of drought. Hence, we conducted a greenhouse experiment in rhizotrons under contrasting watering regimes to explore shoot and root traits and drought avoidance mechanisms in young faba bean plants. Eight accessions were investigated for shoot and root morphological and physiological responses in two watering conditions with four replications. Pre-germinated seedlings were transplanted into rhizotron boxes filled with either air-dried or moist peat. The water-limited plants received 50-ml water at transplanting and another 50-ml water 4 days later, then no water was given until the end of the experimental period, 24 days after transplanting. The well-watered plants received 100 ml of water every 12 h throughout the experimental period. Root, stem, and leaf dry mass, their mass fractions, their dry matter contents, apparent specific root length and density, stomatal conductance, SPAD value, and Fv/Fm were recorded. Water deficit resulted in 3-4-fold reductions in shoot biomass, root biomass, and stomatal conductance along with 1.2-1.4-fold increases in leaf and stem dry matter content and SPAD values. Total dry mass and apparent root length density showed accession by treatment interactions. Accessions DS70622, DS11320, and ILB938/2 shared relatively high values of total dry mass and low values of stomatal conductance under water deficit but differed in root distribution parameters. In both treatments, DS70622 was characterized by finer roots that were distributed in both depth and width, whereas DS11320 and ILB938/2 produced less densely growing, thicker roots. French accession Mélodie/2 was susceptible to drought in the vegetative phase, in contrast to previous results from the flowering phase, showing the importance of timing of drought stress on the measured response. Syrian accession DS70622 explored the maximum root volume and maintained its dry matter production, with the difference from the other accessions being particularly large in the water-limited treatment, so it is a valuable source of traits for avoiding transient drought.

Faba Bean Cultivation - Revealing Novel Managing Practices for More Sustainable and Competitive European Cropping Systems

Faba beans are highly nutritious because of their high protein content: they are a good source of mineral nutrients, vitamins, and numerous bioactive compounds. Equally important is the contribution of faba bean in maintaining the sustainability of agricultural systems, as it is highly efficient in the symbiotic fixation of atmospheric nitrogen. This article provides an overview of factors influencing faba bean yield and quality, and addresses the main biotic and abiotic constraints. It also reviews the factors relating to the availability of genetic material and the agronomic features of faba bean production that contribute to high yield and the improvement of European cropping systems. Emphasis is to the importance of using new high-yielding cultivars that are characterized by a high protein content, low antinutritional compound content, and resistance to biotic and abiotic stresses. New cultivars should combine several of these characteristics if an increased and more stable production of faba bean in specific agroecological zones is to be achieved. Considering that climate change is also gradually affecting many European regions, it is imperative to breed elite cultivars that feature a higher abiotic-biotic stress resistance and nutritional value than currently used cultivars. Improved agronomical practices for faba bean crops, such as crop establishment and plant density, fertilization and irrigation regime, weed, pest and disease management, harvesting time, and harvesting practices are also addressed, since they play a crucial role in both the production and quality of faba bean.