To overcome this limitation, other methods aim to reduce the formation of PDs only, including primer design, and use of different PCR enzyme ...

Dear Sara

know you cannot export touch down conditions into qPCR. However, you can customise the annealing temperature mirroring gel based RT PCR. Therefore My advice to you building on Artur's comment would be

1. Perform a gradient PCR in which you vary increase the annealing temp in SEPARATE reactions in 1C intervals from Tm-3C to TM+2C: In effect this also mirrors your touch down temp range

2. Pick the temp  from your agarose gel in which you obtain the strongest specific band: In general this tends to approximate to Tm-2C or Tm-1C; Above that viz. Tm/Tm+1C/Tm+2C etc you tend to obtain a specific band but less intense. This is NOT suitable for qPCR as the efficiency of the reaction should be >85% and preferably >95%; @ < tM-2C you tend to obtain a strong specific band but sometimes incur extra non specific band which will render you qPCR non specific

3.Now take that RT PCR verified annealing temp and use for the 2nd annealing/extension step of your qPCR reaction. In general this should approximate to 60C (the ideal) but can go as low as 55C (no lower as extension becomes inefficient) and as high as 65C (no higher)

4. Thus, as alluded to Artur's you should devise primers with predicted Tms of 62C to 65C

5. Ascertaining Tm accurately therefore is important for good primer design; To that end I attach a doc I have devised for students detailing salient steps and free ware packages for good primer design

6. Finally I will mention in passing that to maximise the efficiency of your qPCR reaction you should ideally make your amplicons between 100bp and 200bp; More than 300bp and the efficiency will significantly drop; Keep that in mind

Thank you all friends for your answers, I'll try your recommendations..