Quinoa is an emerging new crop for resource-deficient agriculture
Pakistan is one of the water-scarce countries (ca 1200 m3 water available per capita per year) that depends heavily on annual glacier melts and monsoon rains. According to Pakistan Water Partnership (PWP), the amount of water available through these sources is estimated at 153 Million Acre Feet (MAF) or about 190 billion cubic meters; total ground water being ca 24 MAF. Ironically, a greater part of the potentially available surface water is driven into the Arabian sea due to lack of sufficient storage capacity on the path of water flow from north to south of the country. Unless, appropriate water storage measures are taken, the availability of water is deemed to decrease with time especially in view of the relatively fast population growth. The water shortage/scarcity is therefore a serious threat to agricultural productivity in the country in the years to come. We need to appreciate also that under normal agricultural conditions, the vegetation uses around 1000-2000 kilograms (litres) of water for every kilogram of dry biomass produced. Hence, either the availability of water has to increase or (and) we need to look for crop types that combine the characteristics of low water requirement and high water use efficiency.
For maintaining agricultural productivity, availability of sufficient quantity of good quality water is not the only factor. Fertile and healthy soils are equally important. Unfortunately, however, salinization of soils has become a serious factor to reckon with. In Pakistan, over one million hectares of agricultural land is affected by salinity causing a loss in production of around 50 billion rupees. Canal irrigation is considered to be one of the factors responsible for salinization of soils and according to some estimates, 25% of the salt-affected land is in canal-irrigated areas. The situation is considered to worsen with passage of time and therefore remedial measures need to be adopted.
In the face of diminishing fresh water resources and increasing soil salinization it is relevant to evolve (through breeding) or select (from the available germplasm) crop types that could meet human food needs. Quinoa quite well fulfils the requirements both in terms of suitability to cultivation under saline and water deficient conditions as well as to meet human food needs.
Quinoa (Chenopodium quinoa Willd.) is a halophytic (salt-loving) plant that originated in the Andrean region of Peru, Bolivia, Ecuador and Colombia and was domesticated for human consumption 3,000 to 4,000 years ago. It is one of the main food crops in Latin America, but recently has raised interest in North America, Europe, and Asia. In Europe and USA, it has gained popularity as a breakfast cereal and replacement/supplement to rice. The crop’s rise in popularity was reflected in an initiative by a United Nations agency to declare 2013 as quinoa year. It has a variety of uses in the food, feed, food processing and other non-food/industrial uses. Following characteristics make Quinoa a crop of choice for Pakistan not only for domestic consumption but for export as well:
- It is an annual plant that can attain a height of 1-2 meters and takes 120-240 days to mature. Short duration varieties can easily be evolved using conventional breeding techniques.
- Quinoa plants do best in sandy, well-drained soils and the crop could therefore be suitable for southern parts of the country.
- Well adopted to a range of soil pH from acidic (4.5) to fairly alkaline (9.5) making it suitable for diverse soil conditions in Pakistan.
- High salt tolerance; some varieties are tolerant to seawater salinity i.e. EC 52 mS/cm.
- Has low water requirements and thus convenient to grow on rain-fed areas.
- Can be grown on relatively nutrient-deficient soils but is responsive to fertilizer application leading to significant yield increases; resource poor farmers can find it profitable.
- Grows well under relatively cooler conditions with temperature range of -4 oC and 35 oC; some varieties may grow well at still lower temperatures. Light frosts normally do not affect the plants at any stage of development, except during flowering. Thus Quinoa can be a good addition to inventory of winter crops in Pakistan under rain-fed conditions.
- Undemanding and altitude-hardy being grown from coastal regions to over 4,000 m elevation.
- Fair degree of resistance to common diseases; leaf miner (caused by Lepidopteran larvae that feed on leaves) being the predominant disease.
- Quinoa is not a grass, and therefore its cultivation could assist the control of weeds and diseases in areas where cereals are currently continuously cultivated (for example wheat and rice in Pakistan).
- The seed/grain yield (often around 3 t/ha up to 5 t/ha) is comparable or even better than that of wheat (2.5 to 4 tons/ha in Pakistan).
- Fairly good harvest index of around 0.4 compared to ca 0.5 in wheat and rice.
- Grain is high in protein content (14-16%) compared to most common staple grains (except wheat with around 18% protein content) that have 10-12 % protein.
- Thirty-seven percent of quinoa’s total protein is composed of essential amino acids in proportions similar to those found in milk. Indeed, quinoa is an effective substitute/supplement to meat and oilseeds.
- Much higher (double or more) lysine content while methionine and threonine are also higher than other proteinaceous staple.
- Grain has higher lipid content than other cereals (even better than that in corn) and thus a better energy content than others; has lower dietary fibres compared to wheat and barley.
- It is a good source of oil and fat. Saturated fats much lower than others (13% compared to over 25% in others.
- Desirable content of calcium, iron, vitamin E, and several of the B vitamins in the grain.
- Being gluten-free, Quinoa grain can be a favourite for those who are lactose-intolerant; it is popular amongst vegans (non-animal food). Because of some desirable characteristics, it is being considered as a possible crop in NASA’s Controlled Ecological Life Support System for long-duration human occupied space flights.
- Grain sprouts can be obtained within 2-4 hours (no seed dormancy). Sprouts have improved nutritional value and can be added to salads and other cold foods [The grains must be rinsed thoroughly to remove any saponins which if present will give a bitter taste. At industrial level, abrasive dehulling can be used to remove saponin containing pericarp. Saponins that constitute ca 0.1% of the grain by weight can be collected for multiple uses. These are potent natural insecticides with no adverse effects on higher animals including human being. Other interest in saponins could be their antibiotic, fungistatic, and pharmacological properties detergent action notwithstanding. Saponin-free varieties can, however, be developed if required].
- The starch grains in the endosperm are unusually small (2-4 μ m in diameter). This gives the starch unusual functional properties, with several potential uses in the food processing industry. These may be of value in fillers for the plastics industry, low-calorie milk-based products, anti-offset and dusting powders and cosmetics.
- Leaves can be used as green salad.
- Stalks are composted, consumed by grazing animals, and used as fuel for cooking.