02460naa a2200253 a 450000100080000000500110000800800410001902400490006010000180010924501160012726000090024352017140025265000100196665000180197665000230199465300260201770000200204370000180206370000170208170000200209870000180211870000170213677300530215321288852021-09-16       2021    bl uuuu     u00u1 u    #d7 ahttps://dx.doi.org/10.3390/ agriculture2DOI1 aPIVETA, L. B.  aMolecular and physiological responses of rice and weedy rice to heat and drought stress.h[electronic resource]  c2021  aAbstract:Rice is the staple food for about half of the world population. Rice grain yield and qualityare affected by climatic changes. Arguably, rice cultivars genetic diversity is diminished from decadesof breeding using narrow germplasm, requiring introgressions from otherOryzaspecies, weedy orwild. Weedy rice has high genetic diversity, which is an essential resource for rice crop improvement.Here, we analyzed the phenotypic, physiological, and molecular profiles of two rice cultivars (IRGA424 and SCS119 Rubi) and five weedy rice (WR), from five different Brazilian regions, in responseto heat and drought stress. Drought and heat stress affected the phenotype and photosyntheticparameters in different ways in rice and WR genotypes. A WR from Northern Brazil yielded betterunder heat stress than the non-stressed check. Drought stress upregulatedHSF7Awhile heat stressupregulatedHSF2a.HSP74.8,HSP80.2,andHSP24.1were upregulated in both conditions. Basedon all evaluated traits, we hypothesized that in drought conditions increasingHSFA7expressionis related to tiller number and that increase WUE (water use efficiency) andHSFA2aexpressionare associated with yield. In heat conditions, Gs(stomatal conductance) and Es increases may berelated to plant height; tiller number is inversely associated withHSPsexpression, and chlorophyllcontent and Ci(intercellular CO2concentration) may be related to yield. Based on morphology,physiology, and gene regulation in heat and drought stress, we can discriminate genotypes thatperform well under these stress conditions and utilize such genotypes as a source of genetic diversityfor rice breeding.Keywords:genetic diversity; photosynthesis; heat shock protein  aArroz  aFotossíntese  aResposta da Planta  aDiversidade genética1 aROMA-BURGOS, N.1 aNOLDIN, J. A.1 aVIANA, V. E.1 aOLIVEIRA, C. de1 aLAMEGO, F. P.1 aAVILA, L. A.  tAgriculturegv. 11, n. 1, 9-11010009, Jan. 2021.