Of maize, Potatoes and Onions

by Dr. U. Pethiyagoda Ph.D

It is nearly as unthinkable to envisage a successful poultry industry without attention to maize as to embark on milk production without attention to pastures (and manioc). Competitive farming dictates the use of the best possible seed.

I am unaware of any serious maize-growing country which seeks to do so without recourse to hybrid seed. Maybe there is a reason for our tardiness (the department of Agriculture, I guess is nearly a century old) in adopting this technology. An explanation might be opportune.

Anyone who has eaten "corn on the cob" almost anywhere outside Sri Lanka - Malaysia, Indonesia, the Philippines, the US, anywhere in Europe etc. would have noticed that the cobs are invariably full of formed grains, while locally a third to a half may be gaps. Of course, it might not be the only reason but one suspects that the use of Hybrid Seed may well be a very important one. Hybrid corn seed is doubtless expensive, as it has to be skillfully raised from selected parent stocks. Desirable traits probably outweigh this disadvantage.

Maize is an important, ancient and fascinating crop. If I may digress a moment into the botany of this giant grass, cultivated maize is bisexual. The male flowers are the crowns while about two or three leaves close to the stem base bear the future cobs in their axils. The number of potential cobs seems to be a relatively fixed character and breeding efforts cannot successfully increase cob number. The practical approach is to enhance cob size, grain number and successful set.

You may have observed that I refer to "grains" rather than "seed". This is an escape because botanically, each of the objects we eat is in fact a fruit! Each of the strands of the long silk that adorns the top of the infant cob terminates in a grain.

A microscopic pollen grain falling on a strand has to grow down what must seem to it, a relatively enormous distance to the incipient fruit to effect fertilization. It is easy to see why under adverse conditions (untimely rain, excessive dryness, poor winds etc) many sites must fail to be fertilized. Hence poor setting. In a rather cunning arrangement to encourage cross pollination, the male flowers generally ripen and shed their pollen before the tassels on their own cobs are receptive.

Even the belated efforts to widen the use of Hybrid Maize) I suspect a few enterprising growers have managed to bring in small amounts of seed and their experiences should be most illuminating) are commendable.

Reference to the Irish or European Potato (the common potato) is relevant. Many farmers in Sri Lanka are dependent on this crop. However, I believe it is a wrong choice. If at all, we should be growing it as a curiosity or a gourmet item for the affluent. Do not misunderstand me, the potato is a superbly nourishing item, stores very well and tastes divine and we should not be deprived of its virtues.

Agreed - but still I say that we should not grow it commercially! After all, Europe selected, introduced, improved and grew it widely because at that time it was recognized as one of the most efficient converters of sunshine (aided by other factors) into edible starch. Why then discourage its cultivation?

Potatoes are planted as sprouted tubers or tuber pieces. About fifteen hundredweights are generally planted per acre. In commercial farming in potato growing countries, a yield of twenty to thirty tons per acre is average. Under our conditions, we would be lucky with six and exceptionally so with ten tons.

Consider that in order to get fifteen hundredweights of sprouted seed potatoes, we may have to start with perhaps twenty to thirty hundredweights of potentially edible tubers. So in reality, with a harvest of six tons fresh, we are in fact getting a four to six fold return.

Consider the costs, seed potatoes, fertilizer (I believe about a ton of mineral mixture and several tons of compost per acre) fungicides and insecticides, labour and other costs just to get six tons of potatoes. Had we instead imported these six tons of edible potatoes, it is a fair bet that we would need less than the foreign exchange cost alone of fertilizer, pesticides and fuel.

I have heard it said that in season, potatoes in Bangladesh sell for the equivalent of eighteen Sri Lankan cents per kilo! Unbelievable, but economic even if wrong by a factor of 100 times!

I believe the critical factor is latitude. Only if our island shifts to 20 degrees north or south (from its present position of 7 degrees north) can we confidently expect potatoes to be commercially worthwhile.

Until then, little point in battling. It is for this very same reason that we would waste effort if attempts were made to grow lentils (or "massoor" or "mysore" dhall). Best left to Iran, Turkey, Afghanistan and such northerly latitudes.

Fortunately alternatives for potato are available. Sweet potatoes are one of the most important crops in North Carolina, South India has virtually a whole Institute devoted to the study of manioc (Cassava), a type of aroid yam (Colocasia or Alocasia) that grows under virtual paddy field conditions and yielding some thirty tons of fresh carbohydrate in a three-month growing season has been reported.

True they may not have all the virtues of the Irish or European potato but the cost advantage is considerable.

Jak and Breadfruit are also presently important sources of "casual carbohydrate".

Another factor is very relevant. Bacterial Wilt, caused by a Bacterium is a common and serious disease of potato. It is a very difficult pest to get rid of once introduced or multiplied. It attacks other solanaceous crops of which important ones are tomatoes, brinjals, and capsicums (including chillies). This too argues against unrestricted potato cultivation.

Another example worthy of mention is the Onion. We are considerable consumers of the Red Onion (also called shallots or spring onion). Latterly, perhaps as a result of the LTTE insurgency, large onions (Bombay Onions or "big Onions" in post-IPKF-generated patriotic terms!) have largely displaced the small version. Just as well, on commercial grounds. As all know, red onions are grown from separated segments of bulb clusters while the Big Onion is raised from seed.

Hundredweights of small onion bulbs at horrendous cost are required to plant an acre as against a few ounces of big onion seeds and not at prohibitive cost. It is likely that the preference was based on a totally mythical preference of the Sri Lankan housewife (a terribly harassed and deprived species) for the red onion.

Ironically, the evident suitability of Mahaweli areas for the Bombay Onion was being well established at precisely the times of deprivation when housewives stood in line outside the co-operatives at four am for scarce items and when salads with onions were only available in the Parliament canteen!

It is because the above three technological advances need to be rigorously examined and vigorously pursued that I have dared to intrude into areas of which I cannot claim expert knowledge. That they all cry out for concerted attention is evident. While not quibbling about numbers, I would consider it ample reward to be shown where I may be materially wrong.

Incidentally, whatever happened to "Lanka Parippu" a brilliant achievement of our breeders and agricultural researchers?