By Alex Kirby BBC News Online environment correspondent

Many African scientists believe genetically modified (GM) crops offer the only hope of avoiding mass starvation on the continent.

The claim is made in a TV programme. It says that in dozens of African countries, "biotechnology has sparked a mood of optimism".

The programme recognises the long-term fears of anti-GM campaigners, but says Africa's dilemma is acute.

And it says many people in Africa think biotechnology can offer better health and prosperity as well.

The programme is The High-Tech Harvest, made by Television Trust For The Environment (TVE). It is part of TVE's Earth Report series, shown on BBC World.

In Uganda, where bananas are a staple food, the programme filmed a farmer, Margaret Nabwiire.

 Click here to watch BBC World and its report on GM crops in Africa.

She says: "I expect a great deal from this banana plantation - school fees, uniform, pencils, books. It will help me to meet all these costs."

Hungry nation

She is able to produce fruit which mature faster, give much higher yields, and are disease-free.

Bananas are an African staple

Dr John Wafula is director of African Biotechnology, a consortium set up by the industry, which helped to fund the making of the programme. He is based on Kenya.

He tells TVE: "If you take a country like Kenya, over 80% of our people are involved in farming, and yet they cannot provide adequate food for a population of 30 million people.

"As an African, my crusade is to ensure that my people are not dying of starvation. If there is anything I can do to contribute, I would be very willing to do that."

Africa can barely feed its people now, the programme says - and by 2050 its population will probably have doubled. To keep pace with current consumption, world food production "has to double by 2020 - an unlikely target".

Therapeutic bananas

Tests of a GM sweet potato developed by scientists in Kenya suggest it could increase yields by up to 80%. Professor Nora Olembo is director of Kenya's Industrial Property Office.

Anti-cholera precautions in South Africa

She says: "If our people are hungry and there is a way of getting food produced with resources that are donated, then we should put those resources where they are needed to produce that food."

Cholera is a serious problem in South Africa, but experts say vaccinating everyone at risk would be prohibitively expensive. The vaccine's stability depends on temperature, too, so it could be useless before it reached people in rural areas.

Jocelyn Webster works for African Biotechnology in South Africa. She tells the programme: "There have been developments like the banana that's been modified to have cholera vaccine incorporated into it.

"At a cost of maybe five cents we could have distributed vaccine in a food easily eatable by most of the people in this country who normally would not have access to it. Africa's needs are far different from Europe's."

In the dark

South African cotton farmers tell TVE they can increase yields using a GM variety, and cut pesticide spraying. One says inhaling the spray can be fatal, and he thinks the new cotton will save lives.

But Isabella Masinde of the Intermediate Technology Development Group (ITDG) tells the programme: "I am scared. I need more information, just like all the other farmers in Africa.

"Even the policy-makers do not have this information. They're just listening to debate from the developed world."