Beat the heat: Breeding, genomics, and gene editing for high nighttime temperature tolerance in rice.

High nighttime temperature (HNT) is a major obstacle in rice production worldwide. It severely impacts spikelet fertility and induces grain chalk, the two undesirable factors leading to yield and quality decline in rice. Recently, major efforts have been undertaken to understand the genetic mechanisms underlying HNT tolerance. Here, we highlight phenotypic diversity and recent studies on breeding, genomics, and gene editing targeting this trait. These studies point to the challenges in the process as HNT tolerance has so far been found only in non-adapted varieties, and no known modern cultivar bred in the United States is able to withstand exposure to HNT during the reproductive stage. At the same time, identification of the tolerant genotypes enabled genomics, opened up tortuous but promising approaches for breeding, and showed a path for gene editing towards HNT tolerance. The recent advances have set a strong foundation for addressing this current and looming threat.