«Andean roots and tubers: Ahipa, arracacha, maca and yacon M. Hermann and J. Heller, editors Promoting the conservation and use of underutilized and ...»
Although there are extensive taxonomic treatments of the Lepidium species of Australia (Hewson 1982) and North America (Al-Shehbaz 1986a, 1986b) as well as a general monograph on the genus (Thellung 1906), information is scarce on the species endemic to South America, and in particular about Andean Lepidium species, which belong mostly to the sections Dileptium and Monoploca (Thellung 1906). These species are interesting because they grow at high-altitude habitats, up to 4500 m asl, and include the cultivated species maca. Probably maca was domesticated in San Blas, Junín, between 1300 and 2000 years ago, but little is known about its origin (Matos 1978; Rea 1992). It is believed that in the 16th and 17th centuries maca had a wider range of cultivation than today. The existence of wild species of different ploidies, in some cases sympatric with the cultivated taxon, indicates that extinction of possible ancestral species has not proceeded too far to prohibit understanding of the evolutionary history of the group. Consequently, taxogenetic studies may disclose the ancestral species of the cultivated taxon. The identification of related wild species could be applied to the genetic improvement of maca, if these carry useful genes that could be transferred by hybridization.
3.2 Geographical distribution Maca is an Andean crop of narrow distribution. It is restricted today to the suni and puna ecosystems (Bonnier 1986) of the Departments of Junín and Cerro de Pasco of Peru (Fig. 8a) at elevations above 3500 m and often reaching 4450 m in the central Andes of Peru (Fig. 8b) (Leon 1964; Tello et al. 1992). The largest cultivated area is found around Lake Junín at Huayre, Carhuamayo, Uco, Ondores, Junín, Ninacana and Vicco. Apparently maca occupied wider areas of cultivation in the past (Johns 1981). In addition to Junín and Cerro de Pasco, presumably, it also was grown in Cusco and in the Lake Titicaca watershed. Some of the writers of the time mention that many natives did not have any other food but maca. It was also used as payment of taxes to the Spanish administrators (Castro de Leon 1990). Its restricted cultivation today indicates that maca may have been in danger of being phased out as a crop.
Promoting the conservation and use of underutilized and neglected crops. 21. 183 At the present time less than 50 ha are being dedicated to the production of maca in Peru and presumably in the world (Tello et al 1992). However, the popularity of this crop is steadily increasing, not only in its area of production but also in large cities because of its putative medicinal properties.
Fig. 8. Geographic distribution of maca in Peru. A: maca cultivation is restricted today to the Departments of Cerro de Pasco and Junin. In the past, it is believed that it was cultivated much more widely, covering from Junin to Puno. B: altitude profile of the main maca production area.
Maca (Lepidium meyenii Walp.) 4 Uses Maca is cultivated for consumption of its root-hypocotyl axis, and is used extensively for medicinal purposes.
The maca ‘hypocotyls’ are eaten fresh, cooked in pachamancas (cooking of meat and vegetables in underground ovens lined with hot stones) or stored dried for later consumption. The dried roots are eaten after boiling in water or milk, and are sometimes mixed with honey and fruit for preparation of juices, and addition of sugarcane rum for cocktails and other alcoholic beverages (Johns 1981; Tello et al.
1992) (Fig. 9). Flour is also prepared from the dried roots for making bread and cookies. Maca is mixed with chuño (freeze-dried potatoes), oca, quinua and soyabeans to prepare different dishes and dessert. Toasted and ground ‘hypocotyls’ are used to prepare “maca coffee” (Castro de Leon 1990).
Local consumers close to the production sites prefer medium size and yellow maca roots. This is because larger roots take longer to cook and the colour preference is due to the belief that yellow roots are sweeter than those of other colours.
Apparently any root shape is acceptable. In general, however, there are no established quality characteristics for this crop. The pharmaceutical industry is now a main consumer of maca, and processes practically any roots that are in acceptable sanitary condition. The main centres of commercialization of maca are in La Oroya, Junín and Huancayo. The total production of maca is estimated to be approximately 320 t/year, and it is possible that the demand is twice as much. In 1995, the cost of 1 kg of dried maca hypotocotyls was between US$1.5 and $2 in the Junín market.
There are now efforts by pharmaceutical laboratories to promote the cultivation of this crop and expand its production (F. Tamayo, pers. comm.).
According to folk belief, maca is an aphrodisiac which enhances sexual drive and female fertility in humans and domestic animals, which tends to be reduced at higher altitudes (León 1964). Sanchez León (1996) presents an interesting account of the role of maca in the conquest of the Inca Empire. The Spaniards when arriving in a hostile environment, such as the puna of Junín, were afraid of losing their horses because of the lack of conventional pastures and their inability to reproduce at high altitudes. They soon learned about the nutritious and fertility-enhancing properties of maca, allowing their horses to pasture in fields of this crop. The conquerors found “well fed babies and tall adults” in the high Andes, which was attributed to their diet based on maca. Owing to these beliefs, maca had a prominent place as a crop used to enhance the reproduction of pigs, chickens and horses. During the times of the Tawantinsuyo, the legend says that before going to war the Incas used maca to feed the warriors to increase their energy and vitality. However, after conquering a city the soldiers were prohibited to consume it as a measure to protect women from their sexual impulses.
Beliefs of fertility-enhancing properties of maca have been partially substantiated by limited experiments in rats, which indicate that gains in fertility are due to the probable increase in the development of the Graaf follicles (Chacón 1990; Rea 1992).
Chemical analysis by Johns (1981) suggests that the fertility-enhancing properties of Promoting the conservation and use of underutilized and neglected crops. 21. 185 maca may be due to the presence of biologically active aromatic isothiocyanates, and specifically due to benzyl isothiocyanate and p-methoxybenzyl isothiocyanate. The latter is also found in mashua (also know as añu and isaño) (Tropaeolum tuberosum Ruiz and Pavon). This species, however, is reputed to be an antiaphrodisiac and antireproductive agent in males, but a promoter of female fertility (Johns 1981). The putative aphrodisiac powers of maca also can be attributed to the presence of prostaglandins and sterols in the ‘hypocotyls’ (Dini et al. 1994). In early times, maca was appreciated not only as nutritious food, but also as a gift to the gods along with corn and potatoes. Mountain Raco in Junín was considered the god of stewed food.
In its honour, the natives buried potatoes and maca there among other offerings.
Maca also was used in beverages with hallucinogenic products in dances and religious ceremonies (Castro de León 1990). Today in the local markets it is advertised as an aphrodisiac, stamina-builder and ferility-promoter. It is also often promoted as a cure for rheumatism, respiratory ailments and as a laxative. Dried maca roots are ground to power and sold in drugstores in capsules as a medicine and food supplement to increase stamina and fertility. One of the leading pharmaceutical laboratories in Peru has started an aggressive advertising campaign promoting maca capsules as a magnifier of sexual potency. Other medicinal properties attributed to maca are regulation of hormonal secretion, stimulation of metabolism, memory improvement, antidepressant activity and effectiveness in combating anemia, leukemia, AIDS, cancer and alcoholism among others. None of these properties, however, has been substantiated by scientific research. Because of these putative virtues, maca is also known by the name of Peruvian ginseng (Rea 1992).
5 Properties The nutritional value of the dried ‘hypocotyl’ of maca is high, resembling that found in cereal grains such as maize, rice and wheat. Fresh hypocotyls contain 80% water.
Dry maca hypocotyls have the following composition: 59% carbohydrates, 10.2% proteins, 8.5% fiber and 2.2% lipids among a few other compounds (Dini et al. 1994).
Maca has a large amount of essential amino acids and higher levels of iron and calcium than the white potato. In addition, it contains important amounts of fatty acids, of which linoleic, palmitic and oleic acids are the most prominent. Maca is also rich in sterols and has a high mineral content, in particular Fe, Ca and Cu.
Alkaloids are also present, but these have yet to be determined (Dini et al. 1994) (Table 1). Maca has a strong and peculiar flavour which is not acceptable to many people.
In most cases, this is disguised by other components used in preparation of juices and other concoctions. The compounds responsible for maca flavour are unknown and may be other than glucosinolates (T. Johns, pers. comm.).
Table 1. Summary of the most prominent chemical components of maca ‘hypocotyls’ (after Dini et al.
6 Genetic resources and breeding The largest collection of cultivated maca and wild species of Lepidium is maintained at the Universidad Nacional Agraria, La Molina, in Lima, Perú. This collection is the product of four expeditions to the Departments of Pasco, Junin, Huancavelica, Ayacucho and Cuzco. It consists of 93 accessions of maca and 41 of wild species. In addition, 38 experimental lines, mostly progenies from single plant selections, are maintained in the collection (Table 2). Most of the maca accessions come from Pasco and the eastern side of lake Junín and higher part of the Mantaro valley around Huancayo. It includes the whole range of morphological types for ‘hypocotyl’ shape and colour (Table 3). The majority of the accessions have yellow or purple ‘hypocotyls’. The curator of the collection is Ing. Rolando Aliaga. At the present time a controlled-temperature facility is being built at the university campus for longterm storage. The collection is being evaluated in situ in Junin and Pasco. A smaller collection consisting of approximately 33 accessions, mostly duplicates of the first one, is located in the International Potato Center at the station in Lima. The curator of this collection is Dr Michael Hermann. Details of accessions can be retrieved through the web site of the System-wide Information Network on Genetic Resources (SINGER) of the Consultative Group on International Agricultural Research (CGIAR) on the world wide web (http: / / www.cgiar.org, then click on “Inter-Center Initiatives”, then on “SINGER”).
Table 2. Number of accessions of maca and other Lepidium wild species maintained at the Universidad Agraria, La Molina
The seed is stored in commercial freezers at approximately -15°C on silica gel, which assures germination close to 95%, based on a 5-year observation period. Prior to introducing the seed in the freezer, it is dried on silica gel for 2 weeks. Seeds of maca are maintained by growing 20 plants per accession, until they produce enlarged ‘hypocotyls’. These are then vernalized at 5-7°C for 2 months in moist peat. Seed germination tests are recommended every 2 years (M. Hermann, pers. comm.).
No official descriptors have been published for maca; however they are in preparation as part of the research activities of the programme “Raíces y Tuberculos Andinos” based at the International Potato Center in Lima.
In other institutions, the collections are fairly new and therefore regimes for renovation and maintenance are not well established yet, which in many cases is due to lack of funding and resources. There are areas of maca production which are not represented yet in the existing collections. These include the western side of lake Junín and the Department of Huancavelica, where there are a few reports of cultivated maca. Wild species are poorly represented in the existing collections. A systematic collecting effort needs to take place from Huanuco to Puno and Bolivia.
Genetic improvement of maca is restricted at the present time to root selection for colour, size, shape and other desirable attributes. Selected roots are replanted later for seed collection. The small size of the flowers and the large numbers of flowers per cluster at different stages of development, which approaches 50, make quite difficult the emasculation and elimination of flowers not appropriate for this procedure because of their different ages. The oldest flowers in the raceme are on the outside whereas the youngest are at the centre. These difficulties are aggravated by the cleistogamous nature of the flowers which need to be emasculated using magnifying aids while they are still closed but before there is any evidence of pollen shedding. Furthermore, emasculated flowers do not seem to survive well, probably because of damage to other floral structures during the delicate procedure.
Promoting the conservation and use of underutilized and neglected crops. 21. 189 7 Ecology Maca has one of the highest frost tolerances among other native cultivated plants, since it is able to grow in the puna where only alpine grasses and bitter potatoes thrive (Bonnier 1986). The natural habitat of highland Peru where maca is grown has an average minimum temperature of -1.5”C and an average maximum of 12°C (Tello et al. 1992). Frost is frequent and temperatures can get as low as -10°C. The relative humidity is high, with an average of 70%. The natural soil in the maca production area is acidic, having a pH of 5 or less (Tello et al. 1992).