In a world of more than 250,000 different species of flowering plants, just three grasses - rice, wheat and corn dominate as the sources of most of the food supply for human beings. All three have been objects of agricultural experimentation and exploitation by human beings for more than 6,000 years. Long before the discovery of Mendel's laws, in 1900, human ingenuity had created about 100,000 cultivated varieties of rice suited for every purpose, land and season, with about 70,000 of these varieties cultivated by farmers in India. It is remark able, and to some a very sad story, that just in the, last two decades more than half, the human population of the world has come, to depend on only a handful of these varieties for their sustenance. Obviously, the high yielding varieties of rice developed by modern techniques of plant breeding have not caused a green revolution in India in the sense wheat seems to have, since the latter has given more than projected yields in the past ten years. One of the failures of modern agricultural sciences is that the technology evolved to increase yield in plants is biased towards individual elite varieties rather than to all varieties evolved by human beings in the past 10,000 years of domestication.
We are now desperately looking for any technique that would increase yield in rice, even by a few per cent, to produce food for the increasing population. Hybrid rice, now growing in about a third of the rice growing areas in China, has about 25% yield increase over the high yielding modern cultivars thanks to the phenomenon of hybrid vigor or heterocyst. However, there are indications that these varieties may not be as successful in the more tropical conditions of India. The potential increase in yield through any breakthrough in genetic engineering with rice remains unknown and unpredicted. It is against this background that one should appreciate Dr. Richharia's recent small book of 132 pages offering "a possible one-grain rice revolution" with novel suggestions for establishing "rice gardens" that could produce 100 tonnes per hectare per year (as against about 15 tonnes per hectare for three crops through conventional techniques of rice cultivation). The romantic title of Masanobu Fukuoka's work, The One-Straw Revolution" is better adapted here for this book, written by a scientist and summarizing nearly 45 years of his research on certain fundamental and potentially useful properties of rice plants. We read a book for what it says, and often also for who says it. Richharia knows the rice plant as well as any human being can, and his experience and contributions remain unmatched by any single rice researcher in India.
Richharia has organized his book carefully beginning with a lucid introduction to his they is in Chapter II, and exploring the more involved applications that require some knowledge of crop production, in the subsequent chapters. The appendices clearly bring out how he has been championing, for more than 25 years, the adoption of his clonal propagation techniques for yield enhancement in certain varieties and hybrids of rice. I did find some sentences cumbersome to read, about half a dozen typesetter's spelling errors, an odd list of 48 names in 'Hindi (in a book otherwise fully written in English), and an appendix on "In vivo and in vitro clonal propagation in rice" only of peripheral interest to the theme of the book. However, these are very minor shortcomings in a book that has so much to offer, is so well documented, and clearly sets forth the importance and implications of clonal propagation in rice.
The thrust of Richharia's message is that 17 to 61% increase in yield can be obtained by clonal propagation of certain varieties, and that this technique can be exploited not only for yield increase but also for overcoming the problems of (a) sterility among hybrids and tetraploids (b) maintenance of quality in aromatic varieties of rice, and (c) submergence of seedlings during flooding. Clonal propagation also helps in the better management of ratoon crops and plants produced through tissue culture methods, and provide a degree of resistance to insects such as the stem borers and gallfly. What is this new technique of clonal propagation that is claimed to offer an alternate means of increasing yield in rice? Tillering, the ability to produce branches from the axillary buds located at the nodes, is a feature common to many grasses. All tillers derived from a main stem possess identical genetic makeup. While tiller production is considered undesirable in most major cereal crops, yield in rice is dependent upon the ability to produce a number of healthy tillers that would eventually produce panicles and grains. Primary tillers develop from the main shoot about 10 days after transplanting. Secondary and tertiary tillers develop from the primary tillers, and in about 50 to 60 days after transplanting, a single seedling in a hill could have given rise to about 25 tillers. A significant feature of tillers is that 50 to 70% of them develop panicles that produce mature grains about the same time as the panicle on the main stem thus yielding more grains per hill. Tillering capacity is a varietal characteristic, as often pointed out in this book.
What Richharia offers is a procedure to take advantage of this innate perennating capacity of the rice plant to multiply hhe genetically identical clones to obtain some 300 times more man the usual number of tillers from a single seedling during 5 to 6 months of propagation. Additionally - and this is very important - the seeds obtained from the clones, when used to raise a normal crop in the next season, produce healthier plants, offering up to 60% more yield than plants raised from seeds obtained from conventional techniques of crop production. When a seedling has produced two tillers, Richharia suggests separating them from the main stem and replanting all three individually in pots or in a plot. When each one of them has produced two tillers, the procedure is repeated usually in intervals of about 15 days. Under ideal circumstances, with three tillers (x = 3) per split, and about 8 such splits (n = 8) between February and July, as many as xn = 6561 clones can be obtained from a single seed. Tiller separation seems to enhance subsequent vigour and growth of the clone resulting in the production of more fully- filled and uniformly mature and healthier seeds capable of better yield in the next generation. Richharia is quick to point out that successful tiller production is a varietal character and that clonal propagation technique is merely a manipulation of the untapped but natural potential of the rice plant.
Richharia then proceeds to explain how ihis crucial but simple procedure of physical t separation of tillers from each other can be applied to stubble left in the field after harvest, to a whole ratoon crop, to a large field after transplanting is over, and to a nursery bed with aged seedlings. Apparently, farmers in Orissa and Madhya Pradesh have been practicing a form of clonal propagation known as beusaning or biyasi where a field with broadcast cultivation is 'ploughed' to split the tillers. Richharia further explores the possibility of applying the clonal propagation technique to improve yield and/or quality in: (1) tetraploids where 40-45% sterility is encountered but propagation of even a few seeds is worth the effort in view of the increased protein content of tetraploid grains, (2) about 300 cultivars of aromatic rice where uniformity in genetic make-up would ensure consistency in quality (and this has great export potential), and (3) seedlings obtained through tissue culture and genetic engineering techniques. Often, in science, simpler solutions have wider applicability. It is interesting to note that Richharia extends his clonal propagation technique to cultivation of plants in a closed system for extended space travel and colonization. This, I submit, is not farfetched, and the rice plant is certainly the most suitable of all cereals for this purpose by virtue of its hardiness, temperature tolerance, perennating habit and ability to grow in aquatic as well as terrestrial media.
Richharia cites examples of field trials conducted in Andhra Pradesh, Bihar, Kerala, Madhya - Pradesh, Mysore, Uttar Pradesh ahd West Bengal to substantiate the claims of yield increase “through clonal propagation. Two obvious questions come to mind while reading this book: (1) What is the physiological basis for yield increase in clonal propagation? (2) Why such a promising technique is not more widely practiced, and why Richharia, himself once an occupant of key positions in rice research (Director of Central Rice Research Institute, Cuttack, and Madhya Pradesh Rice Research Institute, Raipur), has not been able to convince researchers, pla'nners and farmers throughout India ?
As for the physiological basis of yield increase, the only significant finding available so far seems to be the preferential movement of nitrogen and phosphorus to grains rather than to the culms. It is known from other studies that the chemical environment of different grains within a panicle is age- dependent and that younger grains may have more of a growth hormone such as abscise acid than the older and fully mature grains. Also, seed treatment "with certain growth regulators is known to improve productivity in later stages of growth. Perhaps, clonal propagation similarly affects the chemical environment of the seeds whose beneficial effects are realized in the subsequent generation. Obviously, a great deal of research is required to "understand the effects of tiller separation on the autonomous status of the isolated tiller and the development of panicle and grains. Most examples cited in this book are of tillers grown during the long day periods of February to June. While- photosensitive varieties are suitable for this season; insensitive types would start initiating panicles even before the third split can take place. One wonders ii this is the reason why no data is available in this book as to how much more yield can be obtained when the high yielding IR varieties are propagated through clonal cultivation. Could this be a reason, then, for the lack of widespread adoption of this technique - that most of our better yielding or at least fertilizer responsive types do not have the photosensitive gene incorporated in them? Clonal propagation, as described in this book, requires about six months of constant effort to grow, manure, water, weed, protect from pests and diseases, and split and replant the tillers, periodically. Planting these tillers in July would yield grains, not for consumption, but for raising a regular crop in the next season, i.e., in the following July. Yield from this crop, sometime in November, will be the source of food. Because of this extremely long period required to raise plants through clonal propagation, a cost/benefit analysis is required for cultivation under extended field conditions in farmers' holdings.
This little book has much more to offer, than the techniques of clonal propagation. Here, Richharia has summarised some of his lorig-held views and suggestions for an "Indian Hybrid Rice" programme with less emphasis on the use of conventional cytoplasmic male sterile and fertility restorer systems . His suggestions for the use of abnormal floral structures and clustered spikelet types deserve the attention of researchers. Richharia also reveals some of his vast knowledge and appreciation of the "why" of the many practices in rice cultivation observed among the so called "tribal" populations of the country. Indeed, one hopes that he would record in greater detail these traditional techniques of cultivation lest the onslaught of modernity should wipe out knowledge built over many thousands of years.
It is with a fooling of satisfaction that one closes the cover of "Rice In Abundance for All Time Through Rice Clones" - that this most benevolent plant still holds many mysterious ways of feeding the millions.
Author:P. Dayanandan
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