From 1994 CEPESER works studying and proving the potential of production and utilization in-situ of the Sexual Seed (SSP) as a means of generation of genetic diversity and conservation of native varieties of potato of the Andean Tableland of the province of Ayavaca (3,000 to 3,400 msnm; 4°55’LS and 79°51’LO); a niche favorable to its diversity on the upper floor of the low tropical mountains of the Department of Piura, in the Peruvian north; where it is of great importance to increase the existing variability of this tuber in a collective effort of institutions, conservationist families of this region and farmers of other floors ecological potentially users of this limited food resource in Piura.

The joint effort with the conservationist farmers and other interested parties has four principal directions: 1) Monitoring of the conservation of native varieties of potato through the promotion of Fairs of Exhibit and Exchange; 2) The evaluation of the potential for production of Sexual Seed (SSP) of the different native varieties conserved in farmer fields; 3) Evaluation of the effect of the progenies of free pollination (SSP-PL) obtained of the native varieties to produce healthy minitubers in beds of growth and its resistance to the transplant to field, and 4) Evaluation and spread of the families of tubers and new varieties that select the producers in accordance with its culinary preferences, strategies of production and desirabilities of marketing.

The PL progenies evaluated in fields of farmers (beds of growth) during 1997 to 1999 and in four altitudes (1125, 1300, 1800 and 2200 msnm) have shown good effect of seedling, survival from 80% to 98% to the 30 days after the seeding and performance of minitubers/m2 between 1.0 to 5.8 kg/m2 or 125 to 549 units/m2 // . After three years of produced this seed (1996) its effect has not declined with respect to the registered in 1997. The environmental effect has borne a relation direct between the altitude and the performance, not thus with the emergency effect in the different progenies. Eight progenies proven in their resistance to the transplant had percentages of survival of 81% to 90%.

In the initial phases the conservationist farmers who contributed samples of their native varieties in the Fairs, they participated in the evaluations of progenies, and they elected the families of tubers that require in order to renew their reserves or prove new, arisen from the segregation. A new phase is the use of the SSP of native varieties by the farmers for the production of its own material segregante. The performances of minitubers of progenies as; Mansion, Avocado, Tutuma, Pechuquiceña, and Culqueña, in family parcels to 1750 msnm; they are of 2.02, 1.40, 1.35, 1.0, and 0.41 kg./plant respectively. To the same altitude, with 3 g of SSP-PL of the variety Pechuquiceña there occurred 400 kg. of segregantes tubers with characteristics of this variety, almost lost in fields of farmers of the Andean tableland. In the last Fair of Exhibit of native varieties of potato 1998, farmers presented descendants of native potatoes obtained from its sexual seeds.

The high variability, diversity, and fragility of environments in the Peruvian mountains demands for a great creativity in order to achieve a sustainable agriculture and a food security strategy through the rescue of efficient technologies of production, storage and conservation (Towers, J.; 1995).

The sexual seed (SSP) of pollination free (PL) obtained of native cultivars for their long-term conservation and as source of genetic variability is used in the improvement of the culture and recovery of missing genotypes by biotic or abiotic stresses. The great genetic diversity that usually results from these seeds permits the selection of new cultivars in accordance with the needs and preferences of the farmers (CIP, 1994). The former Andean farmers used the sexual seed in order to renew their reserves of tuber seeds and produce new varieties (Salman, 1949; Golmirzaie and Mendoza, 1988; Benz, 1989), as still occurs in some communities of the Cusco (Ortega, 1990). The progress achieved in the improvement of the effect of the seed by nutrition of the plants mother during its formation (Pallais, 1987) and the control of the factors during its storage (Pallais, 1991, 1995); in addition, of the significant interaction family x environment for performance of tubers that suggests that the local varieties should be used as progenitors of families of seed for specific areas (Golmirzaie, Ortiz and Serquén; 1990) increase the advantages of the sexual seed as an appropriate and sustainable system for the generation of variability and conservation in-situ.

Unlike the system of the spread clonal, that requires of many multiplications and exacting sanitary control in each one of them in order to reach sufficient volumes of distribution to the set of producers, with the SSP only are required 30 or 50 g for plantar one has, which opens the possibility of expanding rapidly the use of native varieties, in addition; to be an inexpensive and sustainable form of storage of strategic reserves of the genetic resources to face possible natural catastrophes or genetic erosion.

In the Andean tableland of the province of Ayavaca of the department of Piura, located among the 3,000 to 3,500 msnm and to 4⁰55’ L.S., exist various native or traditional varieties of potato that constitute basic source of the feeding of its population; however, there is registered the continuous decline of the cultivated surface of them and the extinction of others. Since 1988 the Peruvian Plant of Services (CEPESER) intended to restore and multiply vegetatively in-situ these germplasms for the purpose of maintaining the diversity that guarantees the food security of these populations (Ramírez, 1994). Despite this effort, upon concluding the project, the lack of maintenance and control of the warehouses, absence of areas specialized for the multiplication of the genotypes, and unfavorable climatic alterations, they have continued to decrease the restored variability what it makes a priority to undertake its regeneration and conservation, but on the basis of an efficient and inexpensive system.

The objective of this research is to determine the possibilities of producing and using the Sexual Seed of Potato in order to increase, to improve and to conserve in-situ the genetic variability of the native germplasm of this culture existing in the Andean Tableland of Piura, with the participation and direct decision, on this diversity, of the farmers that traditionally have conserved it through vegetative spread, and that for causes // natural or socioeconomic these reserves are vulnerable. To evaluate with the same farmers, both of the Andean Tableland and of other ecological floors of the Sierra of Piura, the potential that have the native varieties in order to produce sexual seed; just like, the effect, performance, resistances and adaptations of these seeds, can be the bases for establishing as alternative system, efficient and inexpensive of strategic reserves of the genetic diversity of this food in a limited region of him. The use of the sexual seed of the native varieties, implies not only the conservation but also regeneration, increase and expansion of the existing diversity and a broader vision of the conservation in-situ

These fairs are carried out annually in the Andean Tableland promoted by CEPESER. In them the conservationist farmers of native varieties of potato, ocas, and ullucos meet to state their collections and exchange genetic material. A registry of the principal varieties stated from the I Fair of Exhibit is available in 1995 (Table 1), also the Directory of the principal farmers who conserve native varieties of potatoes, ocas and ullucos (Table 2).

Table 1. Exhibit fairs and exchange of native varieties of potato of conservationist families of the Andean Tableland

Table 2. Conservationist farmers of the Andean Tableland "High of Cold"

(*) Identification in accordance with the Catalog of True Potato Seed of Potato in Peru. SEINPA

On the altitudinal floor of 1800 msnm, of the locality of Ambrosio in the microcuenca of Ñoma, 17 of these varieties have shown good capacity for production of SSP, from 0.35 g/plant in the variety Huagalina up to 2.78 g/plant in "Black Cashca." Some varieties as Culqueña and Pechuquiceña (S. x chaucha) showed very low production of pollen; however, abundant fruit production (Table 1), which can make possible the production of hybrid seed by natural pollination. In addition to producing SSP the performance of tubers was between 0.75 to 1.5 kg. of potato by plant, in the set of the varieties, which indicates that still low conditions of greater temperature that that of its environment of origin (3,200 msnm) express good potential for adaptation in the production of sexual seed and of potatoes, characteristics important for its greater expansion in the region // .

These results show that these native varieties not only offer facilities in order to conserve them through their seeds sexual, but also; they can be selected to obtain progenies from good adaptation to areas of the central mountains of average altitude (1,000 to 2,500 msnm) of Piura by crossing over with `clones` adapted to warm tropics (Glomirzaie, 1990). In addition; they also make possible the acquisition of hybrid progenies based on the genotypes themselves native preferred by the farmers of the Andean tableland, expanding their capacity for selection of new varieties in-situ (Huamán, 1994).

This is the stage of greater intervention of the producers to characterize the population segregante arisen from every progeny. The `visualization` of the effect and health expressed by the plants of sexual seed that grow in the growth beds generates new expectations and initiatives of the producers toward this alternative.

The PL progenies produced in 1994 and 1996 evaluated in field (beds of growth) have shown good effect of seedling, with values between 17.0 to 18.7 for the Emergency Speed Coefficient (CoV), survival from 80% to 98% to the 30 days after the seeding and performance of minitubers/m2 between 1.0 to 5.8 kg/m2 or 125 to 549 units/ // m2 (Tables 4, 5 and 6). In successive evaluations during three years (1997-99) the seeds produced in 1996 showed rising values until February 1999, declining in August 1999 but with still greater values to the ones registered in 1997. It is possible that the values relatively low of 1997 are due to the state still dormante of the produced seeds 10 months previously (Table 5). In simultaneous evaluation in three altitudes (1,125, 1,800, and 2,200 msnm), the results show that the environmental effect has borne a relation direct between the altitude and the performance, not thus with the emergency effect of the different progenies (Table 6). Eight progenies proven in their resistance to the transplant had percentages of survival of 81% to 90% (Table 7).

Table 4. Evaluation of the progenies of sexual seed of free pollination (SSP PL) from native varieties produced in 1994 and performance in field of its first-generation minitubers in Ñoma (1,800 msnm); prov. of Morropón, Piura.

In the evaluations at the time of harvest of the minitubers produced in the growth beds, the producers carry out their own process of selection of segregantes tuber families in accordance with their desirabilities and preferences of adaptation, resistance, performance, and culinary quality of the different produced genotypes.

In this stage the conservationist farmers who contributed their native variety tuber seeds in the Fairs elect and identify phenotypical characteristics of the families of tubers that require in order to renew their diminished reserves or prove new arisen from the segregation. These working meetings and exchange constitutes the I meet again in the fulfillment of the common objective to conserve this cultural wealth, from the "First Fair of Exhibit of Native Varieties of Potato" in September 1995 in that them or its family members contributed samples of the native varieties that conserve, until 14 December 1997 in that the "daughters" (first-generation tubers segregantes) of those // varieties return to the Andean Tableland by means of the producers conservations that have participated of this event. This moment is significant because it closes a cycle of three years of research project concerning the possibilities of the use of the sexual seed as a means of conservation and expansion of the use of the genetic variability of potato existing in the so much Andean tableland among the inhabitants of this space and for the populations of the microcuencas adjacent to smaller altitude that can benefit for consume and produce not potato // only in greater quantity but in quality.

In the month of February 1998, ten conservationist farmers requested sexual seed from pollination free (SSP-PL) from its native varieties for the minituber production. There was distributed to each 10 gr. of each progeny. In the III FAIR OF NATIVE VARIETIES OF POTATO, OCA, AND ULLUCO IN THE ANDEAN TABLELAND "HIGH OF COLD", AYAVACA (30.9.98) four participants: they presented material segregante from SSP-PL of native varieties in which the generation of new variability became evident into the hands of small farmers who have begun to use the sexual seed in very small areas in order to renew their varieties based on their descent. The other six farmers who used the SSP lost the harvest by effect of excess of moisture during the event El Niño 98.

In the valleys of average altitude (Microcuenca Ñoma and sub-basin San Jorge) among the 1,200 and 2,500 msnm whose nascent are in the margins of the Andean Tableland and where usually is not planted potato, have been installed parcels of use of SSP-PL of native varieties led by farmers in order to examine the possibilities of producing families of tuber seeds of native germplasm beginning in // its sexual seeds so that the farmer elects what genotype him is more desirable in accordance with its characteristics of adaptation and culinary qualities. These native varieties are recognized by the farmers of these areas by their excellent flavor and nutritional value, higher than the commercial varieties; however, its vegetative seeds are never at the disposal of them.

Farmers with those which are used sexual Seed of native varieties:

The performances obtained in the field multiplication of the first-generation tubers produced in the beds of growth, it was from 1.0 to 2.0 kg./plant in Pechuquiceña, Tutuma, Avocado and Mansion, with the exception of Culqueña that had the least performance (Table 2) showing the great yield potential (25 to 50 tn/has) that have these families from // SSP (PL). The most important result of these experiments was the production of a family of 400 kg. of tubers of the variety Pechuquiceña based on 4 kg. or 459 minitubers from their PL seeds; to concern a practically missing variety in the fields of the farmers of the Andean tableland, as it was confirmed in the Fair of Exhibit of native varieties in 1995.

The results obtained in this evaluation study of the potential for production of SSP of six native varieties and of the effect and yield potential of tubers of their PL seeds make it possible to presume that, as well as in Nicaragua (Towers, F.; 1991. 1993) and as propose it Golmirzaie and Don Juan with the `clone` TS-15, it is possible to produce SSP of free pollination or hybrid of good quality in tropics of average altitudes and not only in southern regions of latitudes high.

The production of vegetative material that contains the genetic characteristics of the parenteral native varieties, makes it possible not only to conserve the current genetic diversity based on its similar, but in addition; to increase it and to improve it multiplying the new individuals that arise from the natural or directed crossings. Thus, it is the case of the variety Pechuquiceña, that is almost missing in the Andean Tableland, and that from her sexual seeds it could have been able to produce new tubers with very similar characteristics and with greater health to the variety mother, who constitutes a relevant result by the possibilities that represents this system easily adoptable for the small farmers in order to conserve in-situ // and to optimize the production of the germplasm that autonomously have maintained even the present time. Through the SSP there can be guaranteed low-cost the conservation of the native germplasm over long periods of time (Huamán, 1987; Holle, 1987, Pallais, 1995) to avoid the high costs and problems of rigid schedules of seeding that requires every year the system of conservation based exclusively on the vegetative multiplication (Querol, 1988) and to improve the productivity of these varieties.

REDOMESTICACION, CONSERVATION IN-SITU AND SEXUAL SEEDS

FOOTNOTES/ENDNOTES

1. Program coordinator of Potato of the Peruvian Plant of Services (CEPESER). Street Arequipa 642-60 floor; Piura. Facsimile 074-335997; and-mail: cepeser.per196@cepeser.org.pe