dharanasu for concentration
yogyata fitness, suitability, propriety, ability, capability, appropriateness
manasah of the mind
The mind also becomes fit for concentration.
Pranayama is not only an instrument to balance the mind, but also the gateway to concentration - dharana.
Once the new light of knowledge has dawned through the practice of pranayama, the mind is fit and knowledgeable to move on towards the realisation of the soul. The allusion here is clear that the sadhaka who had to struggle initially to cultivate a yogic way of life by self-discipline and study, now finds his efforts transformed into a natural fervour to progress in his sadhana.