Transforming grain sorghum’s yield potential through trait-based ideotype breeding

Abstract

Sorghum has an inherent ability to adapt to harsh environmental conditions. Further improvements are needed to keep sorghum production feasible under future changing climate. The proposed project addresses this need through extensive field-based phenotyping and development of trait-based ideotype sorghum hybrids specifically targeted for water-deficit and favorable environments. The knowledge, phenotyping tools and germplasm resulting from this project will help enhance water-deficit tolerance and productivity under harsh conditions and help regain acres under relatively favorable environments in the U.S. sorghum belt. To achieve this goal, a multi-disciplinary team is assembled to (i) Increase radiation use efficiency through erect leaf architecture and increased plant height; (ii) Modulate stomatal density to increase water use efficiency under water-deficit conditions and enhance carbon gain under favorable environments; (iii) Optimize stay green trait for improved source-sink relationships to enhance yield and grain protein; and (iv) Explore opportunities to increase seed number and sink strength by altering sink size. Additionally, to ensure newly developed hybrids are less vulnerable different aspects related to increased stem strength is included as a part of this holistic approach. All these objectives are planned to be integrated through crop-climate modeling to fully assess the trade-offs and interactions between target traits and environments. As such, crop-climate modeling will be used to determine effective trait combinations for specific environments, i.e., for water-limited (low stomatal density, stay green, tillering, higher primary rachis branches in panicle) and favorable (erect leaves with increased height, higher plant density, higher stomatal density, improved assimilate translocating hybrids, larger sink size and strength) environments. Findings generated by the team to achieve this goal and approaches taken to integrate these traits into breeding pipelines aimed at specific target population of environments will be discussed.