Zail Singh, 78, the first Indian president from the minority Sikh community, died yesterday, nearly a month after he was injured in an automobile accident. Mr. Singh, who was president from 1982 to 1987, suffered injuries when his car hit a truck. The exact cause of death was not announced. Mr. Singh was president during the height of the 10-year Sikh rebellion for independence in the northern state of Punjab. The militants said Sikhs were discriminated against by majority Hindus. Born May 5, 1916, Mr. Singh trained to become a Sikh priest. He joined the independence movement against British rule and later was a prominent leader of the Congress Party in Punjab. He became a member of the federal parliament in 1980 and was home minister until he was nominated by Prime Minister Indira Gandhi as the Congress Party's presidential candidate.