The technology of clonal propagation, also known as vegetative propagation, was strongly recommended by eminent rice scientist Dr. R.H. Richharia for increasing rice yield. It is a good time to revive this discussion, as this technology can be particularly useful when floods damage crops, as has happened extensively in India and South Asia.
Work on clonal propagation was carried out by Dr. Richharia, former Director of the Central Rice Research Institute (CRRI), Cuttack, for several years, with more intensive research after 1958. A series of papers followed. Much later, in his 1987 book "Rice in Abundance for All Times Through Rice Clones, a Possible One Grain Revolution – A Genetic Forecast", he explained its important benefits.
He wrote that vegetatively propagated plants, or clones, consistently outperformed normal seed plants in terms of environmental stress, drought, resistance to pests and diseases, floods, and salinity, while ultimately producing more grains per unit area. He also noted that this method allowed very rapid multiplication, with a single paddy grain or stubble yielding over forty quintals of grains in ten to eleven months, depending on variety and resources. In addition, clonal technology could be used to exploit hybrid vigour and to reduce yield depression caused by inbreeding.
Dr. Richharia described the process in detail. Paddy grains are germinated in an earthen pot. After 10 to 12 days, seedlings produce tillers, which can be separated after about 20 days and replanted in manured, moist soil. Each tiller grows and produces more tillers every 15 days or so. The separation process continues until the normal time of transplanting in July–August. If started early, say in February, a few seedlings can be multiplied into enough clones to cover an acre of rice field by July–August. By November, a full crop can be harvested, yielding a large quantity of pure seeds.
Through this method, pure seeds can be multiplied and used to raise a normal crop the following season. These seeds are generally superior because the grains are fully mature, healthy, and filled, with fewer chaffy grains, owing to the physiological efficiency of tiller plants. Hybrid seeds can also be expanded clonally to provide sufficient seed for later generations, taking advantage of remnant hybrid vigour.
From experiments, Dr. Richharia observed that yield increases from clonal propagation varied with rice varieties, ranging from 17 to 61 percent compared with normal seedlings. He also found that it could provide some protection against insect pests. By this method, any rice variety could be spread rapidly across a region within a single season, boosting production significantly within one or two seasons.
This technology has special relevance in flood-prone areas. When rice fields are submerged early in the crop cycle, replanting is often necessary, but seedlings may not be available. In such cases, aged seedlings from unaffected fields can be used as a source of clones. Rice clones, Dr. Richharia demonstrated, are resistant to water submergence, making them suitable for flood-prone regions. Special nurseries of aged seedlings could therefore serve as clone sources.
In 1963, an intensive effort was made to popularize this method through twenty-five demonstration trials in 10 villages of Cuttack Sadar Stage II Blocks. Results showed that vegetatively propagated crops gave substantially higher yields than normally raised crops across all varieties, firmly establishing the superiority of this technique.
A recommendation for this technology was included in a program prepared by Dr. Richharia at the request of former Prime Minister Indira Gandhi. This, along with several other recommendations in his plan, deserves wider attention.
---
The writer is Honorary Convener, Campaign to Save Earth Now. His books include The Life and Work of Dr. R.H. Richharia, Man Over Machine, and India’s Quest for Sustainable Farming and Healthy Food
Comments
Post a Comment
NOTE: Hateful, abusive comments won't be published. -- Editor