Dissecting the root phenotypic and genotypic variability of the Iowa mung bean diversity panel

Authors: CHITERI, KEVIN - IOWA STATE UNIVERSITY; ZAKI JUBERY, TALUKDER - IOWA STATE UNIVERSITY; DUTTA, SOMAK - IOWA STATE UNIVERSITY; GANAPATHYSUBRAMANIAN, BASKAR - IOWA STATE UNIVERSITY; Cannon, Steven; SINGH, ARTI - IOWA STATE UNIVERSITY

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2021
Publication Date: 1/27/2022
Citation: Chiteri, K.O., Zaki Jubery, T., Dutta, S., Ganapathysubramanian, B., Cannon, S.B., Singh, A. 2022. Dissecting the root phenotypic and genotypic variability of the Iowa mung bean diversity panel. Frontiers in Plant Science. 12:808001. https://doi.org/10.3389/fpls.2021.808001.
DOI: https://doi.org/10.3389/fpls.2021.808001

Interpretive Summary: Mung bean has long been an important crop throughout Asia, and is increasingly being grown in North America for its nutritional profile, its versatility as a food, and its benefits in agricultural systems. Mung bean is being used in products such as pasta, meat and egg substitutes, and for sprouts and other direct-consumption uses. As a relatively new crop in the U.S., varieties need to be evaluated for suitability in various regions, and breeding work will be required to produce improved varieties for particular applications and locations. This study evaluated 376 mung bean accessions, particularly focusing on root traits. In other crops such as bean, soybean, and maize, root architecture has been shown to be important for supporting robust growth, yield, and resilience to drought. Results from this study include identification of genetic markers for several beneficial root architectures. This work is expected to be helpful for future breeding work in mung bean, helping to develop new mung bean varieties for particular applications and growing areas, for the benefit of farmers and consumers.

Technical Abstract: Mung bean (Vigna radiata (L.) Wilczek) is a drought-tolerant, short-duration crop, with a seed composition of 22-28% protein, 1-1.5% fat, 60-65% carbohydrates, and valuable minerals, vitamins, and antioxidants. We explored the phenotypic and genotypic diversity of 367 mung bean genotypes of the Iowa (IA) diversity panel by analyzing over 9000 images collected at three-time points (days 12, 15, 18 after germination), generated using a hydroponic system, with root structure architecture (RSA) traits extracted using the Automated Root Image Analysis (ARIA) software. Broad sense heritability for days 15 and 18 was higher than those for day 12. Day 12 broad sense heritability (H) ranged from 0.24 - 0.51, 0.22-0.73 for day 15 and 0.23 - 0.87 for day 18. TRLUpper, WID and RDW/TDW had the highest broad sense heritability (0.51, 0.73, 0.87) for days 12, 15 and 18 respectively. Using root ideotype classification, genotypes PI425425 (India), PI425045 (Philippines), PI425551 (Korea), PI264686 (Philippines), PI425085 (Sri Lanka) emerged top five in the topsoil foraging category, while PI425594 (Unknown origin), PI425599 (Thailand), PI425610 (Afghanistan), PI425485 (India), AVMU0201 (Taiwan) were top five in the “steep, cheap, and deep” ideotype. We report promising genotypes that can now be advanced to the greenhouse or field for further testing. Using association studies, we identified significant markers associated with lateral root angle (LRA) and length distribution (LED). Results of this work on phenotypic characterization, root based ideotype categories, and significant molecular markers associated with important traits will be useful for marker-assisted selection and mung bean improvement through breeding.