Punjab Congress chief and former chief minister Captain Amarinder Singh's younger brother Malwinder Singh quit the party and joined rival Shiromani Akali Dal (SAD) on Saturday.
SAD president Sukhbir Singh Badal inducted Malwinder into the party along with his son-in-law Biban Singh.
"The move is unlikely to hurt the Congress, or Amarinder, politically, but family ties will be strained forever," said an old aide of the erstwhile Patiala royal family to which the brothers belong.
Malwinder had applied for the Congress ticket to contest from the newly-carved Patiala (rural) constituency, but was turned down. He had applied for a ticket in 2007 as well, but was not entertained.
Malwinder, 67, refrained from speaking against Amarinder and said he would not contest the January 30 election against his brother (two years older) on a SAD ticket.
But he was critical of his sister-in-law Preneet Kaur (Amarinder's wife) - the minister of state for external affairs - for her "proactive role" in denying him the Congress ticket.
Kaur and Amarinder's son Raninder Singh has been allotted a ticket from Patiala's Samana constituency. "Preneet is blinded in love for her son," said Malwinder, a former army officer.
Incidentally, before resigning from the army in 1975, he had risen to the rank of captain like his elder brother.
Malwinder said he was fed up with the culture of "treachery" in the Congress, which did not recognise his selfless work of 35 years. He admitted he had been touch with SAD ever since Kaur nixed his candidature.
Badal said Malwinder leaving the Congress meant that old and loyal workers did not have any say in the party and reputed leaders were treated worse than beggars prior to distribution of tickets.
"Congress is crumbling under its own weight because it is facing rebellion in 38 seats, and it may touch 50 tomorrow," added Badal, announcing that Malwinder and his son-in-law would get due respect in SAD.