The Tokyo economic summit's agenda will be crowded. Trade, currency and oil issues will be prominent as President Reagan confers with the leaders of Britain, Canada, Germany, Italy and Japan. But it is to be hoped that the summit will respond to public concern, dramatically illustrated by last year's Live Aid concerts, and address the critical issues confronting Sub-Saharan Africa.

As they do so, they will note that there has been progress in numerous African nations to directly address the fundamental causes of the region's difficulties. There has been progress, at last, to provide some hope to millions of Africans who confront malnutrition and who have seen the region's living standards drop. The Tokyo summit partners can act to assist Africans to sustain the productive reforming strategies that are now proving their worth.

An increasing number of African countries have undertaken far-reaching economic reforms designed to ensure more productive and efficient use of resources and revive the momentum of development. Many measures seek to reduce governmental intervention, stimulate private enterprise and encourage savings for productive investment purposes.

Agriculture is a major sector for reform action. Major changes in policy are taking place to provide farmers with meaningful incentives to increase output in such countries as Ghana, Togo, Ivory Coast, Benin, Tanzania, Zambia and Mali. On Zambia's markets, 55 percent more maize was available in 1984-85 than in the previous year, so almost meeting the country's needs for the first time in a decade; then Ghana has boosted cocoa output by 25 percent and Togo has doubled its cotton production.

And then reform programs have directly attacked public-sector waste and inefficiency. Governmental employment is being curbed, productivity in state enterprises is being increased, and private enterprise is being given new priority and encouragement. For example, Ghana and Mali have respectively reduced public sector operating losses by over 80 percent and over 50 percent in recent years. Reform programs for public enterprises are now under way in some 20 low-income African countries.

But such positive strides are no more than a productive start in a region that is still poorer today than it was 20 years ago. Current reform efforts must be seen in perspective for a region confronting an array of long- term, complex, development plagues: the fastest population growth rates are evident here; child mortality rates are high; health care facilities are inadequate; educational programs are weak; urban poverty problems are mounting; and deforestation difficulties abound.

Today's reform efforts can offer hope to millions of the world's poorest people if they are sustained. But the poorest nations cannot sustain such programs from their domestic resources alone -- they need external assistance. Most of these countries shoulder heavy foreign debt burdens, while urgently needing cash to finance imports of goods and services vital to economic stabilization and growth efforts.

The international community has responded to low-income Africa's problems. The scale of general-public support has been an inspiration to all of us directly involved in development. But the harsh fact is that in real terms the net overall resource flows to Sub-Saharan Africa in this decade have barely increased, while the region's difficulties have multiplied. There is now an external funding shortfall to this region of the globe of about $2.5 billion a year for the next few years. This is a funding gap that must be bridged.

The new strategies that African governments are taking and the progress that is so widely and swiftly being registered underscore the fact that bridging the financing gap amounts to a worthwhile investment. Many international organizations, notably the International Development Association, whose future funding is now under negotiation, have worked most closely with African governments to design and support new policy approaches that can bring decent lives to the peoples of Africa. But the degree to which IDA and other agencies can make a critical difference depends largely upon the decisions taken by the leading industrial nations. Let us hope that the summit leaders remember Africa.