It could be said that Rukmini, Lakshmi's mother was in some way instrumental for the popularisation of playback singing in South Indian cinema.
Playback singing started in Indian cinema with Dhoop Chaon (Bhagyachakra in Bengali. Film simultaneously made in both languages).
That was in 1935.
In the south, playback singing for the first time happened quite accidentally, which was not preplanned. And the producer and director of south India, whose work in the cinema field remains unique, the great A V Meiyyappa Chettiar was the person behind the playback singing in South India.
At the legendary Prabhat Studios (now converted as National Film Archives and Film Institute, Pune) a film "Nanda Kumar" was being produced in Hindi and Tamil simultaneously. The legendary Durga Khote in Hindi, and T P Rajalakshmi as Yashoda. The great singing star T R Mahalingam acted as the child Krishna in the tamil version, and I hope this was his debut film also. The voice of the actress who took the role of Devaki, Chettiar is not of appreciable quality. Chettiar replaced her voice by a noted classical singer of that time, Lalitha Venkatraman who was settled in Bombay. This remain the first playback instance in South Indian cinema.
Probably the Hindi composer C Ramchandra might have sung the first male playback in South. C Ramchandra started his career in Tamil, composing music for the tamil film "Jayakkodi" in late 1930s. In the 1941 tamil film produced/directed by the Hindi actor/director Bhagwan, "Vanamohini" C Ramchandra was the composer. He sang also under the nickname Chitalkar, playback to the hero M K Radha.
A glamour girl and singing star of the time Thavamani devi was the heroine. I have got few songs of the film - 78 rpms. Probably this was the first male playback in tamil/south india.
In the tamil film Sri Valli (1945) Rukmini acted in the heroines role, as Valli, the consort of Muruga. The singing star noted for his high pitch singing, T R Mahalingam was the hero. A V M Chettiar was very keen on the success/performance of his films. The feed back from the public, on the film, was not encouraging. It was felt that the singing of Rukmini did not match with that of Mahalingam. Music was governing factor in success of a film those days, and even to this day it is so. Chettiar withdrew the film from the theatres. Rukminis singing voice was replaced with the singing of P A Periyanayaki, a playback singer of the time. And the film went well. Rukmini took this as an insult and disgrace to her, and walked out of other films that she had entered contract with AVM. But chettiar did not mind it at all. And the success of Sri Valli became an inspiration for the other producers also to opt for playback singing for other singing stars also whose voice was not much impressive.
And this paved way for the heores with good looks, but NOT A GOOD VOICE, to play as heros in films. Before that the good looks was not the criteria to become a hero, it was Good voice that was important. Even singing stars of somewhat good voice like T R Rajakumari, G Varalakshmi, T R Ramachandran, etc also sang in the voices of Leela, Jikki, TMS etc etc.
A Note about PA Periyanayaki
A very gracious singer, voice somewhat resemble our P Madhuri.
Her most celebrated film was "Gnanasoundari" produced by Citadel in late 1940s. I hope in 1947 or 48. She sang playback for the heroine M V Rajamma, a singing star of early tamil/kannada cinema. Again this is an example of playback singing getting popularity, a singing star singing in the voice of a playback singer. All the songs sung by her in Gnanasoundari became super hits. "Arul Tharum Deva mathave...", "Jeeviya Bhagyame...", "Vettunda kaikal..." "Kanniye mamarithaye...." etc etc. She has acted in few films also, and I remember she acted in male role as Narada in an tamil film.