GENETIC AND PHYSIOLOGICAL NOVELTIES FOR SALINITY TOLERANCE IN RICE CREATED BY TRANSGRESSIVE SEGREGATION

Guided by the Omnigenic Theory, the overarching goal of this project is to explore a classic phenomenon in plant breeding, i.e.,transgressive segregation, as a non-reductionist approach for stacking optimal physiological properties that synergize towards novel mechanisms of salinity tolerance, beyond the full potentials of individual parents. We aim to integrate a classical concept in plant breeding with modern OMICS-guided biology towards a new paradigm for examining the physiological basis of integrated growth, developmental, and defense processes that define the mechanisms by which plants adapt to stress environments affecting agriculture today and in the future. With rice under salinity stress as experimental system, this project aims to build the foundation for a holistic approach for creating the new generation of climate- and marginal environment-resilient ideotypes, with broad applications to other crops of importance to the U.S. Translation of this foundational project to plant breeding is expected to complement the single-gene approaches of functional genomics to define the profiles of the 21st century crop ideotypesand their growth, developmental, and defense components. The specific objectives are as follows:1) Elucidate the growth processes contributing to the superiority of a positive transgressive segregant (propelling effects) and inferiority of a negative transgressive segregant (dragging effects) in relation tosalinity tolerance (Growth Sustenance Hypothesis). 2)Elucidate the mechanisms regulating plant morphology and architecture that lead to super-tolerancein positivetransgressive segregant and super-sensitivity in nagative transgressive segregant(Adaptive Plant Architecture Hypothesis).3)Reveal other mechanisms underlying the optimal and sub-optimal defense capacities of positive and negative transgressive segregants, respectively,beyond the effects ofsodiumexclusionmechanism (Defense-Beyond-SalTol Hypothesis).