a problem about dna marker linked to a dominant verticillium wilt resistance in tomat

[turkish_scientist_f]

Hi everybody,i am a biochemistry who works in a biotechnology labratoary on breeding plants.i am new here!

i ve been tring 2 optimize a dna marker 2 link verticillium..its a codominant marker and i need 2 detect an amplified product of approximately 1050 bp for resistant plants and 1000bp only in heterozygous and susceptible plants.How ever , although pcr works i just detect an amplified product of 1000bp even i am sure that my plants re heterozious! i wonder that if anyone of u has worked on verticillium, and what results u got? thanks

[kmunson779]

1000 and 1050 bp are not very different sizes... are you certain you can distinguish between these two bands on your gel?

[turkish_scientist_f]

Of course,we can distinguish even 15bp distance in another tests..and also the people who developed that marker could get that double bands, i dont know whats wrong with mine,i need an alternative primer to test verticillium wilt resistance