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by S. Sureshsundar, Lecturer, Faculty of Agriculture, Eastern University, Chenkalady

Almost all of the population of Asia consumes rice as staple and that amounts to 60 percent of the total world population. About 95 percent of the world's rice output is grown in Asia and that amounts to 550 million tonnes a year. By year 2020 the world population will have swollen to around 8 billion people 5 billion of whom will be rice consumers. Today only around 3 billion people consume rice so world rice production must increase by 60 percent in the next 18 years to meet the needs of the year 2020.

The future poses a major challenge to meet the demand from the increasing population. Increase in production will have to be met under increasing limitations in land for rice cultivation and irrigation water and concerns about the environment. There is virtually no more tillable-land available to grow rice. Future gains must be made solely by improving rice yields and on top of that there is an imperative to use fewer harmful chemicals as fertilizers and for pest control.

A new plant type must be developed to address some of the short falls of the present high yielding varieties. New parents or source of germplasm should be identified to build a plant with an entirely different architecture with the improvement of the physiological aspects of modern rice for increasing yield potential and this rice can be called as 'Super Rice'.

There will not be any practical limitations in developing the Super Rice once the development of new plant type and hybrid rice are perfected. The work on Super Rice started in 1988 and the seeds of Super Rice have been available for testing in several countries.

The potential yield of this Super Rice could reach 15t/ha, under tropical conditions, as compared to the present potential yield of 10t/ha. To achieve the goal of 15t/ha, IRRI has exploited two strategies of breeding, (a). crossing tropical japonica x indica and (b). deploying heterosis of hybrid rice technology. The first strategy could increase the present yield potential by 25 percent or from 10 to 12.5t/ha, while the second strategy could further increase the yield by 25 percent or from 12.5 to 15t/ha.

If we look the characters of this Super Rice it has fewer but stronger stems or tillers and there are many more seeds on each rice panicle. The present varieties posse half of the plant's weight is grain and half is straw, whereas the new Super Rice plant is 60 percent grain and 40 percent straw. So, more energy goes into grain production, increasing yield by about 20-25 percent. The Super Rice also has vigorous root system so, suitable soil fertility management practices will have to be perfected to replenish the high level of nutrient removal from the soil by these Super Rice. Since the present Super Rice highly susceptible to pests scientists are working on improving its resistance to disease and insects mainly rice stem borer.

Scientists encountered many problems in the development of Super Rice. The present main constraints to the Super Rice include low quality and many empty grains. Most current high yielding rice varieties produce around 100 grains per panicle. The prototype Super Rice produces 250 to 300 grains per panicle, which is too many. The plant simply could not supply carbohydrates and nutrients to fill the grains result in empty grains.

The breeders over come this problem by reducing the number of grains back to 200 which still makes Super Rice as productive as older plant types. Plant breeders have sought to combine desirable characters from many different wild rice varieties, older varieties and their wild relatives are the genetic building blocks for future rice crop where biotechnology simplify the conventional breeders job by dealing with molecular level.

Without the development of the high yielding varieties, prices for developing countries consumers would likely be as much as 40 percent higher than they are today. New varieties will reduce costly food imports by the developing countries and will eliminate the need to convert millions of hectares of forestland to agricultural uses.

A new strain of Super Rice is currently being field tested in China and will be planted in two to three years and expected to fill the stomachs of Asia's vast rice consuming population. The variety of Super Rice tested in China is an important achievement. According to researchers, this Super Rice variety is characterized by high yield, outstanding quality and it is resistance to disease, pests and adversity its top per hectare output in the demonstration area is as high as 12.2ton. This will be a world record high yield according to Chinese scientists and it is noted that the world's highest average yields of rice were reported in California (9.4t/ha).

Over the past three decades, the improvement in human nutrition and health in Asia has largely been attributable to a relatively stable and affordable rice supply. The challenge to produce enough rice for the future, however, remains questioning, as the current rate of population growth outpaces that of increases in rice production. Science has a central role to play in raising rice productivity and solving the major constraints on rice production. Examining molecular, genetic and cellular techniques and consider advances in research approaches for increasing yield and improving the nutritional quality of rice. Some of the identifiable approaches are

1. Plant genomic, knowing the identity and location of each gene in the rice genome is of immense value in cultivar improvement.

2. Molecular biological approaches to increase yield: To produce more biomass by increasing photosynthetic rate and duration and by improving grain filling.

3. Enhancing tolerance to biotic and a biotic stress.

4. Improving nutritional quality in the grain.

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