Seedling root architecture and its relationship with seed yield across diverse environments in Phaseolus vulgaris

Authors: STROCK, CHRIS - Pennsylvania State University; BURRIDGE, JIM - Pennsylvania State University; MASSAS, ANICA - Pennsylvania State University; BEAVER, JAMES - University Of Puerto Rico; CAMILO, SAMUEL - Mozambique Agronomic Research Institute; FOURIE, DEIDRE - Grain Crops Institute Of South Africa; JOCHUA, CELESTINA - Mozambique Agronomic Research Institute; MIGUEL, MAGALHAES - Mozambique Agronomic Research Institute; Miklas, Phillip - Phil; MNDOLWA, ENINKA - Sokoine University Of Agriculture; NCHIMBI-MSOLLA, SUSAN - Sokoine University Of Agriculture; Porch, Timothy - Tim; ROSAS, JUAN CARLOS - Zamorano, Panamerican School Of Agriculture; TRAPP, JENNIFER - Washington State University; BEEBE, STEVE - International Center For Tropical Agriculture (CIAT); LYNCH, JONATHAN - Pennsylvania State University

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2019
Publication Date: 5/1/2019
Citation: Strock, C., Burridge, J., Massas, A., Beaver, J., Camilo, S., Fourie, D., Jochua, C., Miguel, M., Miklas, P.N., Mndolwa, E., Nchimbi-Msolla, S., Porch, T.G., Rosas, J., Trapp, J., Beebe, S., Lynch, J. 2019. Seedling root architecture and its relationship with seed yield across diverse environments in Phaseolus vulgaris. Field Crops Research. 237:53-64. https://doi.org/10.1016/j.fcr.2019.04.012.
DOI: https://doi.org/10.1016/j.fcr.2019.04.012

Interpretive Summary: Root architecture has a significant impact on performance of crop plants but is difficult to measure. For plant breeding purposes it is important to know how root architecture can be manipulated to increase crop performance under different environments including stress (heat, drought, low fertility) and nonstress conditions. Because roots of adult plants in the field are difficult to examine we utilitzed a seedling root assay conducted on a work bench in the laboratory. Seed from 557 dry bean lines germinated in paper towels were examined for seedling root architectural traits: length, number, diameter, etc., after nine days. The 557 dry bean genotypes were examined for yield across a compilation of fifty-one different environments spanning Africa, the Caribbean, and Central, North, and South America. Specific seedling root traits were significantly associated with yield across different environments demonstrating their value for manipulation by breeders to improve crop performance under different stress and nonstress growing conditions. Results from this comprehensive study improves our understanding of the effects of root architecture on yield, which will facilitate development of dry bean cultivars for more sustainable production.

Technical Abstract: Seedling root phenotypes may have important impacts on fitness and are more easily measured than mature root phenotypes. We phenotyped the roots of 577 genotypes of common bean (Phaseolus vulgaris) in three diversity panels representing the bulk of the genetic diversity for recent cultivars in this species. Seedling root phenotypes were compared to yield across 51 environments with an array of abiotic stresses including drought, nutrient deficiency, and heat, as well as non-stress conditions. We observed high repeatability of seedling root phenotypes, significant variation in root phene states between gene pools, strong correlations between seedling and field phenotypes, and significant correlations between seedling root phenes and yield under a variety of environmental conditions. The number of basal roots measured in seedlings was significantly related to yield in 22% of environments, adventitious root abundance in 35% of environments, and seedling taproot length in 12% of environments. Cluster analysis grouped genotypes by their aggregated seedling root phenotype, and variation in yield between these clusters under non-stress, drought, and low fertility conditions was observed. These results highlight the existence and importance of integrated root phenotypes for adaptation to edaphic stress, and demonstrate their value as breeding targets under real-world conditions.