A multi‐environment analysis of winter faba bean germplasm for cover crop traits

Abstract

Faba bean (Vicia faba L.) cultivars for cover cropping have remained unchanged in the western United States over the past century. Although breeding efforts have improved grain production across much of the world, improvement of the crop for cover crop applications (e.g., biomass production at the flowering stage) remains understudied. Therefore, a trial of nine newly developed faba bean lines from the USDA‐ARS and four commercial checks (‘Bell Bean’, ‘V4’, ‘V5’, and ‘Windsor’) was established to evaluate cover crop traits across six diverse testing environments. The experiment revealed significant genotype × environment interactions for winter vigor, nitrogen (N) concentration, and aboveground N yield. Significant genotypic variation was observed for important cover crop traits including winter vigor, spring vigor, aboveground biomass, and aboveground N yield, whereas variation for percentage of N derived from the atmosphere was primarily determined by the testing environment. The study also identified a strong association between early plant vigor and aboveground biomass (r = .71), which offers potential increases in breeding efficiencies. In addition, advanced faba bean lines from the USDA‐ARS were shown to produce twice the biomass of Bell Bean across testing environments, and faba bean line PS18301 produced at least 20% more aboveground N yield in five out of the six environments than the conventionally used cover crop cultivars Windsor and Bell Bean. Faba bean lines in this study may be used by cover crop breeders as parent materials.

Exploration of global faba bean germplasm for agronomic and nitrogen fixation traits

“…More traditional approaches may also be considered including the use of plant height as a proxy for biomass due to the strong trait–trait associations in the present investigation. This association has been reported in other investigations (Brasier et al., 2021; Kubure et al., 2016) and may therefore be considered a robust predictor of biomass yield. This estimation may be further improved with the combination of NDVI and LiDAR remote sensing to screen large breeding trials.…”

“…The present study also revealed some potential challenges to future cultivar development with a relatively small number of faba bean lines measuring less than 90 cm in height when averaged over environments and a narrow range for %Ndfa. Other studies also reported small ranges for %Ndfa (Brasier et al, 2021;Ntatsi et al, 2018), which may represent theoretical limits, lack of genetic diversity for the trait, a limitation of the testing conditions, or that breeding efforts have not actively sought transgressive sergeants. However, significant genotypic differences in %Ndfa (P < .05; 59 ± 4.2-84 ± 4.5%) were identified in a study of eight faba bean lines when using cultivar-specific B-values (Nebiyu et al, 2014).…”

“…In an investigation of regionally adapted faba bean germplasm, Brasier et al. (2021) identified significant genotypic variation for percentage of N derived from the atmosphere (%Ndfa), percent N concentration, and biomass yield. In addition to cover cropping, recent breeding efforts have focused on the development of faba bean plant materials for grain and vegetable production (De Cillis et al., 2019; Khazaei et al., 2021).…”

Steps toward developing legume cover crop varieties: Study of biomass and nitrogen partitioning and within‐plant δ115N variation of faba bean at different growth stages

“…Breeding efforts and management practices in faba bean have shown potential to further improve its N contribution as cover crop and green manure through biomass and agronomic trait improvement (Allito et al, 2020). With regional needs and Wayman et al's (2017) grower survey in mind, Boots-Haupt et al (2022) and Brasier et al (2021) reported the results of research that aimed to improve the BNF of faba bean cover crop varieties in the western United States. Long-term legume breeding efforts continue to demonstrate the complexity of traits controlling BNF, indicating a need for more directed studies on the physiology and genetics of N fixation (Alves et al, 2003;Kennedy et al, 2015).…”

Potential of Faba Bean (Vicia faba L.) for Dual-purpose Vegetable Production and Cover Cropping

“…California's cultural diversity has created a unique situation where locally grown and specialty crops such as vegetable faba bean have strong consumer demands, especially within Middle Eastern, Asian, and Hispanic communities. In addition, California's Mediterranean climate is exceptionally suited for a fall planting of faba bean to take advantage of winter rainfall (Brasier et al 2021).…”