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Dear Bhim

You have two factors, so the good choice is a factorial experiment conducted with Completely Randomized Design ( CRD ) . The source of variance of ANOVA will consist of : NAA ( main effect ) , Bio-fertilizer ( main effect ) ,the interaction between NAA ×Bio-fertilizer and experimental error.

Good Luck

Dear Bhim,

I totally agree with the above answers. I think though that you should also consider a split-plot design which is more convenient for field management during the experiment (e.g. main plots could be the plant growth regulators and split plots the biofertilizers or vice versa depending on which factor has the higher effect, according to the literature).

This design is very helpful, especially if you are going to apply each treatment more than once (different growth stages), which could be the case for the biofertilizers (base dressing and foliar application etc.).

In any case you have a factorial experiment with two factors.   

Dr.Bhim Singh

The best suited design for your trial will be Split Plot Design

The only way that contributes significantly to your study is Box Behnken Design, good luck..

Dear Bhim,

I think you can draw the following paper:

https://www.jmp.com/content/dam/jmp/documents/en/white-papers/split-plot-designs-what-why-and-how.pdf

The split-plot design presented in the second page of the paper seems to be adapted to your problem. As you have 3 levels for the concentration of NAA, you'll can calculate a quadratic effect for this factor and test it's significance.

Of course, it is very important to have several plants by plot.

Hope this can help you,

Pierre Chagnon

I would like to use a completely randomized design  because  you have a factorial experiment with two factors and you analysis ANOVA with interactions.