A vast array of species are still found in the wild, while backyards contain mostly cultivars selected by farmers. Production at commercial level started in the 1960s and is based on outstanding plants taken from rural households where they provide food for the family (Bravo 1978; Pimienta 1990; Barbera et al. 1992). Orchards used foundation material obtained from plants bearing large fruit size, high color, and good flavor. The clones were named based on specific fruit and plant traits. It is difficult to identify plants based only on vegetative traits and most farmers and scientists still use fruit characteristics for descriptive purposes.
Official figures report that Mexico has 42,000 ha of cactus pear (SARH 1994) distributed in the central highland (2000 m) semiarid temperate part of the country, all of them under rainfed conditions. Mean annual precipitation ranges from 400 to 700 mm with a bimodal pattern. Soils are shallow to medium in depth, poor in organic matter, and acidic to lightly alkaline.
As a plant with crassulacean acid metabolism (CAM), cactus pear is able to withstand drought. It is cultivated in small tracts traditionally devoted to maize and beans production, with low revenues. Medical research has found value in cacti as a raw material for products to treat hypoglukemia, diabetes, high blood cholesterol levels, and obesity (Hegwood 1990). Recent research revealed that this plant is also able to thrive in high CO2 environments (Nobel and Israel 1994). Cacti have received attention as a crop to fight global pollution and desertification.
Growers expertise generated by trial and error and recent agronomic advances account for high yields of cactus pear. Production depends on intensity of farming practices, orchard size, and environmental factors such as late frosts and rainfall. Small orchards northwest of Mexico City obtain 8-10 t/ha with minimum effect of alternate bearing. However, growers in semiarid regions obtain less than 5 t/ha, with low labor inputs and low crop management.
Due to dependance on a narrow base of cultivars, there is a temporary (three months) market saturation, which is associated with falling prices and low returns. It is desirable to extend the harvest season either with earlier or later ripening cultivars or crop management practices.
At least 95% of production in Mexico is for domestic comsumption. Cactus pears are eaten as a snack, and sold peeled and slightly chilled by street vendors. Harvest season starts late in June and extends through Sept. However it is possible to widen the market window if other cultivars are marketed (Fig. 2). High soluble solids, white flesh, and juiciness are praised by Mexican consumers, while foreign markets prefer yellow and red-fleshed cultivars.
In this paper we attempt to provide a reference for growers, brokers and researchers about cultivars currently grown and marketed in Mexico. For many areas of the world cactus pear still remains an unknown fruit crop.
The most productive area near Mexico city is known as Las Piramides, because it is located around the monuments (pyramids) erected by the ancient inhabitants of the Teotihuacan Valley. This area relies mostly in a single cultivar 'Reyna' or 'Alfajayucan' grown under intense management in commercial orchards. A different situation is observed in the north central area (Guanajuato, Zacatecas, and San Luis Potosi states) where it is common to observe mixed orchards of several commercial cultivars. Cactus pear grow wild in feral land and in semidomesticated way in family plantings.
In any small grove it is possible to find a sample of cultivars as well as wild un-named materials, some of which could be readily included as commercial cultivars (Fig. 2). This allows for the availability of Opuntia products for an extended season. The reservoir for a formal breeding program is enormous and almost untapped.
The cultivars reported in Table 1 are the most well known and marketed. Six of them 'Reyna', 'Cristalina', 'Naranjona', 'Chapeada', 'Amarilla Montesa', and 'Roja Pelona' share about 90% of production.
In Mexico it is possible to provide freshly harvested fruits for almost six months under present culture practices (Table 1). Earliness and late maturing traits are important to extend the market. Cultivars such as 'Charola' and 'Fafayuco' are appropiate to extend end of season sales, but they are not commercially important yet. The possibility of widening the harvest season for the most preferred clones such as 'Reyna' (Queen) needs to be explored. This cultivar is the most important in Mexico, with an estimated production of 75,000 t annually. It ripens from early June to Aug. (Mondragon and Perez 1994).
Fruit quality is determined by several visual and organoleptic traits. Mexican consumers prefer white-fleshed types and 'Reyna' is the standard of qualiy. According to our analysis favored traits for primary selection were: large fruits (>120 g); juicy flesh; high soluble solids (sugar content >15%); edible portion >50%; and thin peel (<0.5 cm); despite the fact that thin peel is inconvenient for handling. Low seed content, as well as small, soft seeds are also considered high quality traits, because seeds are swallowed along with the pulp, total seed weight <6 g/fruit is acceptable. A high ratio of aborted seeds is desirable beacuse they are smaller and softer than the normal seeds. Parthenocarpy in cactus pear needs to be exploited.
The fruit size and productivity of 'Cristalina' is remarkable; fruits averaged 213 g, and yield up to 25 t in commercial groves. Another interesting trait is the presences of blush in 'Chapeada' which is atractive for some consumers. Even though it is not as juicy as 'Reyna' the 'Roja Pelona' and similar clones are gaining importance, due to its attractive flesh color, which ranges from light red to purple. There is some evidence that this cultivar could be marketed internationally.
Cultivars with yellow flesh are presently of secondary importance but this may be due to insufficient publicity. For quality traits such as seed and solid soluble content are well in the range of acceptability which is enhanced by striking peel and pulp color. 'Naranjona' is the most consumed yellow-fleshed variety but it is being replaced by 'Amarilla Montesa' because of its higher ratio of aborted to normal seeds.
'Charola' and 'Cardona' are still collected from wild stands and are highy appreciated in local markets. Both cultivars are able to remain in the plant for up to three months, and are also highly tolerant to handling and resistant to pests and diseases. Yellow and red fruits are under represented in commercial orchards but the trend is to diversify orchards in order to meet future demands of foreign markets.
|Cultivar||Peel||Flesh||Weight (g)||Length (cm)||Width (cm)||Edible portion (%)||Seed wt (g/fruit)||Aborted seed (%)||Peel thickness (cm)||Soluble solids (°Brix)||Flesh juciness (1 = dry 4 = juicy)|
|Chapeada||Green w/blush||Light green||133||7.6||5.4||51.1||5.0||4.6||0.50||14.0||4|
|Roja Pelona||Green-reddish||Deep red||180||9.4||6.2||61.0||5.6||2.1||0.40||15.0||2|
|Fig. 1. A) Mature cactus pears in full production on a family plot in central México.|
|B) 'Reyna', a white-fleshed cultivar.|
|C) 'Naranjona', a yellow-orange fleshed cultivar of cactus pear.|
|D) 'Cristalina', a white-fleshed cultivar.|
Fig. 2. Harvest season of cactus pears in central México.