(April 4, 2003 – Updated: September 4, 2006)

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a) Ecosystem

The Central Valley of Catamarca, where the plantation of Fincas de Ambato S.A. is located, is, on phytogeographical terms, part of the Arid Chaco ecosystem, which in turn is part of the vast natural region referred to as the South American Chaco area (Map 1). The Arid Chaco area (south of the Greater Chaco area), with about eight million hectares, covers part of the territory of Catamarca, Córdoba, La Rioja, San Juan and San Luis. The area of Villa Dolores, Córdoba, where it was first introduced and cultivated in Argentina, is located in the south sector of the Arid Chaco area.

The Central Valley of Catamarca is shaped like an isosceles triangle, enclosed by the Ambato and Ancasti mountains to the west and east, respectively, with its base open to the south. The valley has a total area of 200,000 has.

This ecosystem’s own features make it different from the original jojoba location or other ecosystems where jojoba was introduced and proved to be commercially successful, such as Israel (Table 1 -CJ). The Arid Chaco area also differs largely from the Monte Desert, a drier ecosystem convergent with that of the original location of jojoba (Orians and Solbrig, 1977), where ambitious jojoba projects were implemented almost concurrently under the protection of the same tax deferral law used in Catamarca (Table 1-CJ).

These differences hindering the interpolation of technical information, along with the lack of information at the local level, caused these projects to need specific technologies for use in the Arid Chaco area based on the results from their own plantations.

b) Genetic Material

Fincas de Ambato used the genetic material available in Argentina back at the time of establishment. It should be noted that until projects were implemented under the tax deferral law there was virtually no market for jojoba cuttings in Argentina, as a result of which there was no reason for implementing a major commercial program for jojoba cuttings.

The genetic material used for these plantations was obtained from cuttings of plants grown in Catinzaco (La Rioja), Las Oscuras (Córdoba) and Pomancillo (Catamarca). In turn, these had come from wild plant seeds from Arizona –mostly- and California. Even though the towns of Las Oscuras and Pomancillo are located in the Arid Chaco area -where there were clones for which production data were in fact available- there were no records of the behavior, production or other parameters for any of the clones used at the onset of the project. Accordingly, their adaptation to this ecosystem only became known once planted in the field.

These on site observations soon showed a significant genetic variability among clones, in features so important as the plant’s architecture; salinity resistance; resistance to clay soils, floods, weed and fungi; cold tolerance; and vernalization requirements for flowering.

b 1 ) Genetic Variability

Genetic variability is an invaluable tool for plant breeders, given that it provides the genes needed to face a plague or disease or modify an undesirable feature of any given species. However, from the agronomic-commercial standpoint, the existence of a non-uniform population renders handling extremely more complicated by hindering extensive cultivation practices, agrochemicals use and efficiency, the use of irrigation, pruning tasks, etc., thus raising its operating costs and making marketing of the product more difficult as well, given the impossibility to offer a uniform product in due time.

In commercial agriculture the idea of managing parcels of olive trees, vines, banana trees, apple trees or any other species comprising mixed varieties is unacceptable. There is no reason why this should be different as regards jojoba. However, it is quite easy to find a mixture of genetically different clones in almost every parcel planted prior to 2000.

It was not long before such genetic variability became a serious obstacle to plantation management and, consequently, to achieving the predefined goals:

b 1.1 ) Plant Architecture

Planting clones with different architectures in the same parcel prevents the extensive use of agricultural machinery and may even lead to the need to use different machines, depending on the clone. A good example is set by stunted plants, which need to be pruned very differently from erect plants to make way for harvesters. In many cases, this problem is magnified as a result of replanting with clones that are architecturally different from the original.

The use of different clones in the same parcel entails management problems that are not easily overcome. For instance, smaller size plants show a more efficient use of water due to their smaller transpiration area as compared to bigger plants. However, because they are planted in the same lot, even in the same row, differential irrigation is not possible, as a result of which a decision need be made concerning which plant will be benefited, thus decreasing efficiency in the use of irrigation water. It is worth mentioning that irrigation water is generally pumped from deep aquifers and thus accounts for one of the highest costs entailed by plantation maintenance.

Clone architecture should also be kept in mind when designing the plantation scheme. In lots where the clones are planted equidistantly (e.g.: 2 m x 5 m), smaller size plants take longer to cover the soil than bigger plants do. Until covered by grown adjacent jojoba cuttings, those empty spaces are annually invaded by weed that will need to be fought longer (up to 3 years more) than necessary for bigger plants. This amounts to a significant extension of the plantation’s weed control period.

In order to quantify this problem, regard should be had to the fact that weed is one of the greater obstacles for planting jojoba in the Arid Chaco area. As is the case with any other desert plant, jojoba is truly weak in the presence of dense vegetal strata, particularly gramineae, which is currently the most remarkable case in Catamarca. Also, there is significantly less competition in their original location as there is virtually no summer rain and winter weed is C3 weed -unlike the summer weed (C4) found in the Arid Chaco area- and, accordingly, growth is much less aggressive. C4 gramineae (Cenchrus, Chloris, Setaria, and Trichloris, mainly), which prevail in the area’s herbaceous tapestry, have a daily growth rate in excess of 6.6 gm/m2 of dry matter (Ayerza and Ortubia, 1986). Undoubtedly, the jojoba planted 6 months before the beginning of the rain period, which is still adapting to the new environment, is not up to competing by itself against this overgrowing weed.

The technology available at the onset of these projects was not ready to help jojoba plants fight this aggressive competition: before 10 days had elapsed after clearing, the herbaceous stratum would cover the jojoba again. The manual and mechanic clearing mechanisms used were not up to doing the work at the required speed. It should also be noted that, back then, there was no knowledge based on which herbicides could be used without damaging the small jojoba plants

This sort of situation put so much stress on a jojoba plant that it can actually die. However, they rarely die during the summertime. Usually, the plants –particularly those under three years of age- become so weak that the existence of any negative factor -such as frost- will affect them to an extent greater than normal and cause them to die. Another example is set by the aggressive action of fungi, which benefit from the humid microenvironment resulting from the lack of direct light and weed evapotranspiration. The final result is a generalized delay in development, and no effort to revert it is possible until the next growth season. This means that the growth of weed during the summer causes a delay of up to one year in the growth of jojoba.

b 1.2 ) Frost resistance

Frost is one of the most serious obstacles to jojoba production in the Arid Chaco area, as was the case back in the 1980s in Arizona. There, the solution was based on two converging lines of work:

- Selection of clones with long vernalization requirements.

- Decrease in the plants’ metabolic activity.

- Selection of clones with long vernalization requirements.

Since open flowers die at temperatures of 0°C, whereas the closed bud can take several degrees below zero, the selected clones were clones with sufficiently long vernalization requirements in order to prevent the buds from opening until the threat of frost had subsided (Dunstone, 1996).

- Decrease in the plants’ metabolic activity.

Progressively decreasing the summer-end/early fall irrigation frequency up to zero irrigation levels by the beginning of winter causes the plant’s metabolic activity to go down and the plant becomes dormant, thus becoming significantly more resistant to frost than during active growth periods (Nelson, 1996).

At Fincas de Ambato, the high mortality rates for certain clones at their early stages –reaching 50% in specific lots during certain years- can be attributed to two main causes:

* low genetic resistance to frost when young; and

* active growth state due to one or more of the following factors:

- deficient rooting (calling for irrigation over the winter season), and/or

- high soil-humidity levels caused by excessive irrigation, and/or

- abundant rainfall during the fall, which renders the plants sensitive to frost.

b 1.3 ) Vernalization

It was not until the end of the last decade that the need to subject jojoba to a variable period of cold temperatures in order for buds to flower was shown. The number of hours of exposure to cold depends on the genotypes. Nevertheless, temperatures between 13 °C and 18 °C for a period of at least 20 days have been found to be necessary to end dormancy in most commercially available genotypes (Dunstone et al., 1985a, 1985b, 1984). Even though this requirement is met by the Arid Chaco area, the margin is very tight (Ayerza and Sibbett, 2001), which turns it into a restriction for genotypes requiring relatively long vernalization periods.

Among the clones initially planted at Fincas de Ambato, there were evidently genotypes with extremely short vernalization requirements. During the plantation’s early years, it was common to see clones with open flowers in June and July, thus exposed to the frost which dries the flowers and hinders good production levels.

c) Replanting

The low resistance to frost shown by some clones over the early growth stages leads to high mortality rates which, in addition to raising investments in cuttings, also rendered plantation management more difficult as a whole. The replanting process causes a plantation to comprise plants of different ages (and, consequently, with highly different management requirements), and this hinders work standardization and results in efficiency losses.

Therefore, in addition to the genetic variability existing in a plantation comprising a large number of clones, there is also chronological variability due to forced replanting

d) Cuttings

The development and acclimatization status of the cuttings to be planted is of great importance. It is not uncommon to find plantations that fail because the cuttings used only had 2 to 4 pairs of leaves, and the cuttings were rooted by means of a process where, even though they could take root, the roots did not grow to an extent sufficient to allow fast adaptation to the environment.

Cuttings such as the ones described above are usually obtained through a fast and relatively inexpensive rooting process (normally takes between 3 and 4 months, at the most). This rooting practice is significantly faster than the traditional one, which requires at least 5 to 6 months, and includes the use of a hotbed to stimulate root development, and at least 2 months for acclimatization, during which the special greenhouse conditions are mitigated and the plants are prepared for the different, harder field conditions (Palzkill, 1984). Even though this “fast” method may be useful in some cases, the plants thus obtained are much less adaptable than those obtained through the “longer” process, and they should not be used in areas where frost exposure is possible

f) Male Population

Planting the male plant rows using seeds provides the plantation with a genetic diversity that will decrease the possibility of sex incompatibility. Using this methodology is advisable where no male clones, duly tested with the planted female clones, are available. However, this alternative poses an obstacle impossible to overcome in obtaining early crops. Since female clones are propagated asexually, their chronological age is that of the original, thus being sexually mature and able to start producing as soon as they adapt to the new planting situation and the required climatic conditions to flower and pollinate are met. Accordingly, plantations thus propagated start commercial production as from the third year. However, this requires, in addition to the appropriate climatic conditions, sufficient pollen, which entails having sufficiently grown male plants (from a sexual standpoint) and as regards the number of flowers reached.

As regards those plantations where no male clones are planted, three years after the seeds are planted, their foliage levels are reduced and they are still not mature. Accordingly, the pollen level available for fertilization is much lower than the ideal ratio used to illustrate potential yields (For further details, see Jojoba Pollination in Catamarca.)

g) Climatology

By analyzing the main climatic parameters prevailing over the life of the plantation it is possible to infer their influence on the establishment and development of these plantations.

Suspending jojoba irrigation near mid-fall until such time as the threat of frost has subsided is the most effective agronomic resource for preventing frost damage.

Obviously, this is a valid resource insofar as there is no rainfall sufficient to push the plant’s active growth. However, the analysis of the information provided in Table 2-CJ shows that there was significant rainfall during April and May 2000, at levels way above the historical mean, and sufficient to drive the active growth of jojoba plants. This evidences the need to have cold-resistant genotypes, since the fall irrigation suspension technique will not be effective every single year.

In new plants, humidity availability drives the surfacing of new, tender sprouts whose intra-cell water will freeze if exposed to temperatures below zero, and this defrosting will cause cell rupture and the death of new tissue. For this new growth, plants use the scarce reserves accumulated over the most recent period of their short lives and, before these can be restocked through photosynthesis, the low temperatures will prevent normal metabolic activity and even the creation of new photosynthetic organs by killing the new leaves. Accordingly, the plant’s reserves decrease. The repeated occurrence of this process would cause the plant to drain its reserves and it would no longer be able to survive in the field. In addition, should these plants –which rarely make it to the field with more than 2 pairs of leaves- lose any of their acclimatized leaves (due to reasons such ants, fungi, and mechanic damage), the plant would have no further possibility to accumulate new reserves and it would only survive if it has carbon hydrates sufficient to generate a new pair of leaves in order to restart the life cycle. Table 4-CJ shows that, in 2000, there was frost over 13 days, which frequency is much higher than the historical mean. The agronomic practices resorted to in order to mitigate the damage sustained by small plants over years such as 2000 are as follows: perfect weed removal, yielding rough soil not covered by any brush whatsoever (so that the soil will release heat to the environment, thus contributing to increased temperatures) 1m to each side of the plant, and the continuous watering of the plants (by means of the irrigation equipment) during frosts, thus preventing the temperature from falling below 0°C.

e) Clone variety selection

Even though jojoba was introduced into Argentina in the south end of the Arid Chaco area (Villa Dolores, Province of Córdoba), it was never grown as commercial grain in this ecosystem until the 1990s. This is why, at the early stages of the plantations set in the Central Valley of Catamarca, very little information was available on jojoba adaptation to the environment, and there were virtually no data concerning its behavior subject to specific cultural practices (Ayerza, 1993, 1990c). The information currently available as regards jojoba management and behavior in the Arid Chaco area under a domestication and commercial production regime was clearly generated and applied at the Central Valley plantations established as a result of the projects carried out under the incentives provided for in the tax deferral law.

The selection of varieties that fit the region and the determination of the cultural practices required for cultivation are the essential basis to achieve commercial success with jojoba (or any other species) in a new ecosystem. Where such information is not available the alternatives come down to not planting at all or generating the necessary information (Palzkill, 1996; Dunstone, 1996; Benzione et al., 1996; Benzioni, 1995; Yermanos, 1982).

The research and domestication works performed have determined the great genetic variability of jojoba, which provides the species with great adaptation ability through the selection of the proper genotypes (Kolodziejczyk et al., 2000; Ayerza, 1999; Ayerza, 1990a, 1990b; Ramonet, 1988). Even though in the early stages the selection process used to be lengthy and complex, at present there are tools such as early selection and cloning, which allow to determine and largely multiply the superior jojoba genotypes over periods as short as three years (Benzioni et al., 1999).

The clones selected out of the genetic material available at Fincas de Ambato have yielded between 387 and 425 kg/ha three years after planting, with a 5 m x 2 m plantation scheme. These yield levels match those reached at the original location through clone varieties selected for the Sonoran Desert and through experimental plantations in the Catamarca Valley itself (Ayerza, 1996; Ramonet y Morales, 1985).

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