Real-time PCR analysis for 36 genes in ZS97, IRAT109, NIL-ZS and NIL-IR. The left figure for each gene illustrates its expression profile in ZS97 and IRAT109; right figure illustrates its expression profile in NIL-ZS and NIL-IR. The colored lines denote the expression profile of the 36 drought-responsive genes: blue indicates allele from ZS97 and red indicates allele from IRAT109. The x-axes are three time points of drought stress treatment, and the y-axes are scales of transcription ratios determined from the real-time PCR were ln-transformed. D0, before drought stress; D1 and D2, two stages of drought stress.