UC Davis researchers have published a rice DNA microarray that covers nearly all the 45,000 genes in the rice genome. According to a report:

Ronald and her colleagues used the new rice microarray to investigate gene expression changes when plants are grown in the light versus the dark. They then combined this gene expression data with biochemical pathway data to correctly predict the function of genes whose role was previously unknown. The newly identified genes carry out light-related biochemical processes such as photosynthesis and photorespiration.

The rice oligonucleotide near-whole genome array, called the rice NSF45K array, is publicly available here.