You want to said the amount of DNA or Quality, If quantity low near about 20 ng/ul, no problem, because final solution is 200 ul.

Thank you.

The quality and the quantity of the DNA both are not very good.  260/280 is 1.4-1.6 and the yield is varying from 3-18 ug/ml. I am using the elution buffer is 50 ul, so the final volume is 50 ul.

Hi Amrita, it depends upon what you are trying to do next with the DNA. You said you are getting 3-18 ug/ml which is tons of DNA for PCR. Is the tissue ground up in liquid N2? Usually that improves the extraction process. Also as you are working with woody plant callus so it may require a little harsh/strong extraction process to get good yields. I hope it helps. 

Thank you @Anirudha R Dixit. 

I'll be using that DNA for Methylation sensitive amplification polymorphism (MSAP) studies. But I never used liquid N2 for crushing. That may be the reason for not getting high yield. 

Crush your sample with PVPP or add PVPP after crushing during homogenization in extraction buffer. It will help.

Use liquid nitrogen for crushing, add pre-warmed (65 C for at least 10 mins.) extraction buffer and add PVPP while homegenizing.

Crushing the callus with liquid N2 will help. You can also try CTAB method for this extraction in that case use preheated extraction buffer.

Try using around 100mg, or maybe even slightly less. I have often got better yields with less starting plant material. Also, give each reagent in the kit a little vortex before use, to make sure they are homogenous, especially if the kit hasn't been used in a while. Make sure there is no precipitate in buffer AP1 (again, more likely if the kit been unused for a while), by heating it in a water bath for up to 30 seconds while swirling. You can increase the incubation time after elution with buffer AE up to ten minutes, which sometimes improves yield. Finally, instead of eluting in 100ul, try extracting twice from the same sample if you can, and eluting both into the same final tube in 50ul each. 

Using N2 is important and the sample should never thaw during the process. Be liberal with your use of N2 and grind it until it is a powder and homogeneous when buffer AP1 and RNAse A are added.

I'm struggling with good DNA yield too with the DNeasy kit, but with just some genotypes. Have you extracted effectively from that genotype you are using callus for with other tissue? I'm extracting from roses and most all the roses give me adequate yield and quality for PCR. However, there are a couple related roses that just isn't working well. The concentration is very low and the PCR's are not working with actin primers as a check. I tried less material (50mg versus 100) and that didn't help. I've been using very young tender new leaves as well, which usually works nicely. Have others found some genotype dependent issues that are just hard to overcome maybe because of some secondary metabolites that are unique perhaps?