Showing papers by "International Potato Center published in 1985"

Updated listing of potato species names, abbreviations and taxonomic status

Abstract: Tuber-bearingSolanum species described since 1753 are listed alphabetically. A three-letter abbreviation for numerous species not included in Simmonds (1963) are proposed. Some pertinent taxonomic notes are provided for all species names. The systems of classification proposed by S.M. Bukasov, D.S. Correll, J.G. Hawkes, and C.M. Ochoa have been used to determine the current taxonomic status of each species.

Influence of growing and storage conditions on the subsequent performance of seed potatoes under short-day conditions

Abstract: Healthy seed tubers were produced at altitudes of 240, 800 and 3280 m above sea level and stored under two different conditions in Peru. The six lots of tubers were then planted at all three altitudes to give eighteen treatment combinations. Results from these and other trials showed that storage conditions had less effect on yields than previous growing conditions. Highland seed yielded on average 30% more than healthy seed from warmer lowland sites. This effect of seed origin was more pronounced in the cultivar and replanting sites characterized by less abundant foliage. Although the number of stems produced per tuber were similar, seed tubers from the cool highland site produced more root and foliage weight per shoot than seed from warm, lower altitudes. The results, which are at variance with that could be expected on the basis of theories of physiological age, are discussed.

Potato production using tissue culture in Vietnam: The status after four years

Abstract: Farmers in Dalat, Vietnam, (1500 m asl) have established a unique method of using in vitro plants as a source for planting material (1). The rapid adoption of this approach was attributed to several factors. Farmers had been using degenerated seed of cultivars susceptible to Phytophthora infestans, resulting in low yields and decreasing area under cultivation. Three new high yielding cultivars were introduced as clones: CFK 69.1, B71-240.2 and Atzimba and were named as V4, V8 and VI2, respectively after having shown good P. infestans resistance and given high yields. No seed tubers were available for these new cultivars. This communicat ion reports the evolution of the demand for and use of cutting technology in the spread of these new cultivars f rom late 1980 to late 1984.

Chemical control of pink rot of potato (Phytophthora erythroseptica PethyB.)

Abstract: Field trials have been carried out for seven years to control pink rot (Phytophthora erythroseptica) at the International Potato Center (CIP). This disease has been a serious problem in the maintenance of a germplasm collection at the CIP’s Experimental Station at Huancayo, Peru (3300 m.a. s.l.). Pink rot annually causes serious loss of germplasm accessions, particularly diploid cultivars. Protective and systemic soil fungicides and soil fumigation with Basamid (Dazomet 98%) did not diminish the incidence of pink rot. Ridomil 5G (Metalaxyl 5%) applied at planting time with a preplanting fumigant reduced disease incidence from 31% of infected tubers to around 1%. Optimum control and yield increase were achieved by using Basamid at 300 kg/ha + Ridomil 5G at 30 kg/ha.

Performances of true potato seed families derived from intermating tetraploid parental lines

Abstract: Four different sets of true potato seed (TPS) families, representing a total of 262 hybrids derived from intermating tetraploid clones were evaluated in three different locations in Peru. Significant differences were observed among families in tuber yield, uniformity and transplant survival rate in the field. Several families produced an average tuber yield of more than 1.0 kg per plant, with a tuber uniformity of some families approaching that of standard varieties. Hybrid TPS families gave higher tuber yields and more uniform tubers than families from open-pollination. On the basis of an observed family-environment interaction for tuber yield, it is suggested that locally adapted cultivars or advanced selections should be used as parents to generate TPS progenies for specific areas.

Tissue culture propagation of trees

Abstract: Conventional methods of tree propagation; whether vegative or from seed, are often slow and difficult. Such shortcomings often pose a barrier to the rapid genetic improvement of many economically i...

Verticillium wilt of potato in central Peru

Abstract: Studies in the 1950’s indicated thatVerticillium alboatrum was present in potato fields in the irrigated coastal valleys of central Peru. No further studies were carried out in Peru until those in the late 1970’s initiated at The International Potato Center. So far, Verticillium wilt of potatoes has been observed in several valleys of the coast as well as in highland valleys at elevations up to 3400 m. Although the frequency of isolation ofVerticillium sp. has been much greater in the highlands, the disease is of less consequence there because of low temperatures during the growing season. The most common symptom observed in the field is early senescence, including yellowing and stunting of the foliage. Typical “wilt” symptoms are rarely found. Both in the coastal valleys and in the highlands, onlyVerticillium dahliae has been identified. Although no studies on losses and the economic importance of Verticillium wilt of potatoes have been done, it is clear that the two most important crops used in rotation in coastal valleys of central Peru, potato and cotton, are severely affected.

Field infection of potato by the Solanum apical leaf curling virus (SALCV)

Abstract: Potato plants grown from true seed were naturally infected with the Solanum apical leaf curling virus (SALCV) at the high jungle site near San Ramon, Peru. Tubers from these plants were greenhouse indexed. Symptoms of SALCV infected potato plants include apical rolling, stunting, delayed emergence, weak plants, hair sprouts, and tuber dormancy. These symptoms superficially resemble certain aspects of unusually severe current season potato leafroll virus (4) infection or those of the aster yellows and stolbur mycoplasma diseases (5). Up to 12 percent of the indexed plants were naturally infected with SALCV and SALCV was demonstrated in approximately half of the tubers that produced hair sprouts.

Breeding for resistance to Globodera pallida at CIP

Abstract: Breeding for resistance to Globodera pallida, at the International Potato Center (CIP), is directed at pathotypes P4A and P5A. The polygenic nature of resistance and the variability of pathotypes complicate breeding and testing for resistance. Recurrent selection for resistance genes and for agronomic characteristics is used to increase resistant gene frequency in potato populations. Mass seedling screening, as an early indicator of segregation ratios in a progeny, and a petri-plate technique for accurate assessment of resistance in potato clones have proven to be useful aids in selecting for resistance. Clones with partial resistance could be grown by farmers under certain conditions; partial resistance may also be useful in breeding programmes. New differential or tester clones which are better adapted and resistant to P5A populations should be utilized in the Andean region. Although Solanum tuberosum ssp. andigena has been the main source of resistance, especially to pathotype P5A, the CIP breeding programme should now turn to wild species in order to broaden the base of resistance.