microshoots were developed of 2,4-D induced callus but fails to develop roots in same shoots
you must change your medium.
You must you some diffrent auxin. For example NAA or IAA have better effact on rooting than 2,4_D.
Rooting in shoot depends on type of auxin and plant or concentration of auxin. Please could you tell me the plant you working on it. Then I give you right answer. Good luck
Low-salt medium and low-intensity light may enhance rooting. In many cases, buds or shoots obtained on 2,4-D containing medium are difficult to root. You can try to propagate shoots on 2,4-D free medium.
try again with changing auxin if u used 2, 4-D, than u should try with IBA but i can't suggest u the IBA concentration (but don't use NAA and IAA with IBA) bcz i don't know on which crop u working.
try IAA 1 ppm with MS media and u can also try Citrate, succinate, and 2(N-morpholino) ethane sulfonic acid (MES) as per my knowledge, All the best