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Effect of high temperature (HT) on anthocyanin (ANS) accumulation and its relationship with reactive oxygen species (ROS) generation in color rice kernel was investigated by using a black kernel mutant (9311<i>bk</i>) and its wildtype (WT). 9311<i>bk</i> showed strikingly higher ANS content in the kernel than WT. Just like the starch accumulation in rice kernels, ANS accumulation in the 9311<i>bk</i> kernel increased progressively along with kernel development, with the highest level of ANS at kernel maturity. HT exposure evidently decreased ANS accumulation in 9311<i>bk</i> kernel, but it increased ROS and MDA concentrations. The extent of HT-induced decline in kernel starch accumulation was genotype-dependent, which was much larger for WT than 9311<i>bk</i>. Under HT exposure, 9311<i>bk</i> had a relatively lower increase in ROS and MDA contents than its WT. This occurrence was just opposite to the genotype-dependent alteration in the activities of antioxidant enzymes (SOD, CAT and APX) in response to HT exposure, suggesting more efficiently ROS detoxification and relatively stronger heat tolerance for 9311<i>bk</i> than its WT. Hence, the extent of HT-induced declines in grain weight and kernel starch content was much smaller for 9311<i>bk</i> relative to its WT. HT exposure suppressed the transcripts of <i>OsCHS</i>, <i>OsF3&#8217;H</i>, <i>OsDFR</i> and <i>OsANS</i> and impaired the ANS biosynthesis in rice kernel, which was strongly responsible for HT-induced decline in the accumulation of ANS, C3G, and P3G in 9311<i>bk</i> kernels. These results could provide valuable information to cope with global warming and achieving high quality for color rice production.