Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/27/2021
Publication Date: 11/10/2021
Citation: Barnaby, J.Y., Fleisher, D.H., McClung, A.M., Ziska, L.H. 2021. Identification of the chromosomal regions controlling grain chalkiness that are sensitive to elevated temperature and CO2 levels during grainfill. ASA-CSSA-SSSA Proceedings. Salt Lake City, Utah, November 7-10, 2021.
Technical Abstract: High temperature, especially during grainfill stage, induces grain chalkiness. The presence of grain chalk causes grain breakage during milling, reduces cooking quality and grain appearance, therefore, reducing the value of the crop. In recent years, significant lossess in some rice export markets to Central America were lost due to poor grain quality and chalkiness, likely caused by extremes in high temperature in combination with the current predominant commercial cultivars that were grown. Eight recombinant inbred lines derived from high and low chalk cultivars, Kaybonnet and ZHE733, possessing combinations of 3 major chalk quantitative trait loci (QTL) plus the parents were grown under ambient and elevated CO2 levels in combination with a warmer temperature during grain fill stage were evaluated to investigate the effect of rising CO2 level on heat-triggered chalk formation and yield. Our study revealed that heat induced chalk formation in the chalky parental line was increased by 22% under elevated CO2 condition while in the translucent parental line, less than 1% chalk formation occurred. The inbred line possessing chalk QTL on chromosomes 4 and 2 reduced chalk by 50%, and increased yield by 57% while the other line possessing QTL on chromosomes 1 and 2 reduced chalk by 32%, and increased yield by 25% under elevated CO2 conditions. These results will assist breeders use marker-assisted selection for development of new climate resilient varieties that will minimize chalkiness while maintaining economic value.