Relations between India and Bangladesh, strained for several years because of a series of border disputes, appeared to have improved markedly today with the signing of agreements on several long-grating issues, including an interim accord on sharing the waters of the Ganges River.

The agreements followed two days of meetings here between Indian Prime Minister Indira Gandhi and Bangladesh's military ruler, Lt. Gen. Hussein Mohammed Ershad, the first talks between leaders of the neighboring countries in eight years.

Expansion of the flow of the 150-mile stretch of the Ganges that runs through Bangladesh -- regarded by most development experts as essential to that country's chances for self-sufficiency -- was not definitively resolved in these talks. But both sides agreed in a joint communique to set an 18-month deadline for completion of feasibility studies by technical committees and the implementation of their resulting water flow plan without additional discussion by political leaders.

Gandhi and Ershad also agreed that adjustments will be made to the daily water-flow schedule from India's Farakha Barrage, a dam across the Ganges west of the Bangladesh border, although there will be no increase in the total flow until a permanent solution is found.

India has resisted diverting more Ganges water through a canal north of Farakha connecting the Ganges and a branch, the Hooghly, claiming that this would bring more silt to the port of Calcutta, on the Hooghly. Heavy silting has already made it impossible for large ships to reach either Calcutta or Haldia, a container port 55 miles downstream, for four months of the year.

The water flow has long been a volatile political issue between India and Bangladesh, and each has come up with plans that have proven unacceptable to the other.

Recent political instability in Bangladesh, including Ershad's seizure of power in a bloodless coup last March, has heightened anxiety over the dispute, since resolution of the Ganges-sharing issue could determine whether the current Bangladesh government remains in power. From India's viewpoint, the Bangladesh government in the past was seen as exploiting anti-Indian sentiment over the issue to divert attention from internal political turmoil.

Over the 11 years since India helped create Bangladesh from the ruins of East Pakistan, relations between the two countries steadily deteriorated, most noticeably since Gandhi's return to power in 1980.

After Pakistan lost the 1971 war with India and its eastern exclave became Bangladesh, with sheik Mujibur Rahman as its first leader, the new nation's relations with India appeared to be based on euphoria and gratitude. With Mujibur's assassination in the 1975 coup, tensions began to develop between the countries, particularly after Indian-trained guerrillas began operating in Bangladesh from across the border.

Although then-prime minister Morarji Desai sought to dampen the disputes and cut off Indian support of the guerrillas, when Gandhi returned to power in 1980, Indian-Bangladesh relations began to harden again, and at one point, Gandhi said her new policy was "no kowtowing to neighbors to befriend them."

India and Bangladesh today also resolved another long-simmering dispute involving a tiny land corridor connecting Angor Pota and Dahagram, two exclaves of Bangladesh within India. Known as the Tin Bigha Corridor, the strip of land is only 192 yards long and 92 yards wide, but it became a volatile issue largely because of Bangladeshi refugees crossing into India.

In a 1975 agreement, the territory was leased by India to Bangladesh for 99 years, subject to approval by India's Parliament. Although Bangladesh's Parliament ratified the agreement, India's never did, causing bitter resentment in Dacca.

Gandhi and Ershad today signed an agreement for a perpetual lease on Tin Bigha.

They also moved toward resolution of differences over a tiny sandspit that surfaced 10 years ago in the Bay of Bengal and that has been claimed by both sides since. India calls the islet New Moore Island and Bangladesh calls it South Talpatty.

The dispute came to a head last year when an Indian survey ship landed a contingent of its border security force on the island and put up tents and an Indian flag. Bangladesh protested the move as an illegal occupation, although India said its survey team was merely gathering data to share with Bangladesh.

The island, near the Hamabhanga River estuary -- the border between India and Bangladesh -- is important because the maritime boundary has never been agreed upon, and ownership could affect oil and natural gas rights in the Bay of Bengal.

Although new surveys were agreed upon, the question of sovereignty remains unresolved.