Showing papers by "International Potato Center published in 1988"
TL;DR: The growth, development and yield of seven cultivars were evaluated under field conditions with photoperiods from 11 to 16 hours and light intensities from full light to only 42% light in in 3 experiments in the Philippines, resulting in more branching, increased plant height, more flowering, many secondary stems and delayed plant senescence.
Abstract: The growth, development and yield of seven cultivars were evaluated under field conditions with photoperiods from 11.5 to 16 hours and light intensities from full light (≧12 MJ/m2/day) to only 42% light in in 3 experiments in the Philippines. The longer photoperiod significantly delayed and reduced tuberization, promoted profuse haulm growth, resulting in: more branching, increased plant height, more flowering, many secondary stems and delayed plant senescence. ‘DTO-33’ was least affected by long photoperiod, followed by ‘Red Pontiac’ and ‘Desiree’. Shading resulted in delayed tuber initiation, taller plants, thinner stems, smaller leaves but longer canopy duration and a slightly larger canopy. ‘DTO-33’ was least affected by shading followed by ‘Desiree’, ‘LT-2’ and ’Red Pontiac’. ‘LT-5’ and ‘P-3’ suffered the greatest tuber yield reduction through shading.
52 citations
TL;DR: Of the eight ratios of PTM 1 and PTM 2 tested, all were significantly superior to the use of virgin-female traps, and microencapsulated pheromone spray significantly reduced larval infestation in stored tubers.
47 citations
TL;DR: The relationships between intercepted solar radiation and dry matter production (total and tubers) were established for four cultivars of different maturity classes and using seed tubers of two physiological ages in Tunisia, finding that tuber dry matter, number of stems per plant, tubers per stem and harvest indices were lower in the autumn than in the spring.
Abstract: The relationships between intercepted solar radiation and dry matter production (total and tubers) were established for four cultivars of different maturity classes and using seed tubers of two physiological ages. The crops were grown in an autumn and a spring season in Tunisia. Radiation use efficiencies were lower in autumn than in spring and the quantity of intercepted radiation at tuber initiation was more than two times greater in autumn than in spring due to retarded tuberization in the autumn caused by the relatively high temperatures. In addition, tuber dry matter, number of stems per plant, tubers per stem and harvest indices were all lower in the autumn than in the spring season which explained why tuber yields in the spring season were higher than in the autumn.
42 citations
TL;DR: Irrespective of sites, experiments, or cultivars, days to 50% emergence was closely related to the accumulated heat sum at tuber depth during the day, and tuber initiation was delayed by shade, despite the earlier emergence.
42 citations
TL;DR: The range of sophisticated techniques available in tissue culture is clearly a broad one and some of these techniques are already having a direct and significant impact on potato production and their use is widespread.
Abstract: The range of sophisticated techniques available in tissue culture is clearly a broad one. Some of these techniques are already having a direct and significant impact on potato production and their use is widespread. Other techniques are still at a developmental stage and they offer great potential for direct or indirect improvement of potato production. However, time will be needed before the possible benefits of these types of research are transferred to farmers’ fields.
42 citations
TL;DR: Hybrids between Solanum etuberosum and S. pinnatisectum harboring resistance to titer buildup of potato leafroll virus (PLRV) were reciprocally crossed with tuber-bearing wild species S. acaule andS.
Abstract: Hybrids between Solanum etuberosum and S. pinnatisectum harboring resistance to titer buildup of potato leafroll virus (PLRV) were reciprocally crossed with tuber-bearing wild species S. acaule and S. verrucosum. A total of 47 hybrids with acaule were obtained with the aid of embryo rescue and sterile culturing of embryos from imbibing seeds. All but two hybrids with acaule had low pollen stainabilities or were pollen sterile. Hybrid seeds from crosses with verrucosum were easily obtained, and the triploid progenies were sterile. Hybrid progeny were screened for resistance to PLRV infection by viruliferous green peach aphid and for resistance to titer buildup. Although hybrids did not exhibit resistance to infection, PLRV was not detectable using ELISA. Virus was detected, however, by graft transmission to Datura stramonium. Crosses of fertile acaule-etuberosum-pinnatisectum hybrids with S. phureja, a cultivated diploid, using the latter as pollen parent, produced berries but seed did not complete development and was aborted. Rescue of immature embryos 25 days after pollination by excision from berries and sterile culture produced vigorous, pot-cultured plants. Segregation of susceptible (virus detected) and resistant (virus undetected) progenies suggests simple inheritance.
40 citations
TL;DR: The results indicate that there would appear to be potential for intercropping potato and maize in the hot tropics, and a delicate balance existed between the ability of shade to reduce air and soil temperatures, without causing reductions in tuberization and photosynthesis.
39 citations
TL;DR: Genetic resistance to potato tuber moth was identified in clones of Solanum sparsipilum originally developed for resistance to bacterial wilt and root-knot nematode and transferred to all progenies except those in which S. tarijense was the resistant parent.
Abstract: The potato tuber moth, Phthorimaea operculella (Zeller) is an important pest of potatoes in the field and in stores in warm environments throughout the world In this study genetic resistance to potato tuber moth was identified in clones of Solanum sparsipilum (coded MBN) originally developed for resistance to bacterial wilt and root-knot nematode Resistance to this pest in S sucrense and S tarijense as well as S sparsipilum was exploited in wide crosses with diploid and tetraploid cultivated potatoes, and haploids derived from S tuberosum; hybrid progenies were produced Crosses between resistant S pinnatisectum or S commersonii and cultivated potatoes failed completely, although S commersonii did hybridise with two bridging species S lignicaule and S capsicibaccatum which are slightly compatible with cultivated potatoes Resistance to potato tuber moth was transferred to all progenies except those in which S tarijense was the resistant parent The development of potatoes resistant to potato tuber moth is discussed in the context of population breeding for the lowland tropics
39 citations
TL;DR: The production of sesquiploids, as the 6x-AEP hybrids are called, is discussed as a useful bridging step in the introduction of alien genes from genomes that share little homology with the cultivated genome.
Abstract: Hybridization of synthetic allotetraploids of S. pinnatisectum with S. etuberosum (4x-EP) with S. acaule (2n = 4x = 48) resulted in two individuals that were highly fertile, in contrast to all other progenies. The unique individuals are hexaploids, 2n = 72, while the other progenies are tetraploids, 2n = 48. They are thought to be the products of a union between 2n eggs of S. acaule and normal 1n microspores of 4x-EP. The fertile hexaploids (designated 6x-AEP) produced abundant selfed seed and viable hybrids with cultivated diploid potato, S. phureja, when developing embryos were rescued from berries and cultured before transplanting to pot culture. The extreme variability in chromosome constitution of the hybrids with S. phureja and selfed progenies indicates that addition and substitution lines of etb chromosomes bearing genes of interest to breeders could easily be produced from this material. The production of sesquiploids, as the 6x-AEP hybrids are called, is discussed as a useful bridging step in the introduction of alien genes from genomes that share little homology with the cultivated genome.
27 citations
TL;DR: P-labelled probes prepared by nick-translation, two methods of labelling PSTV cDNA in M13 phage DNA, and RNA transcription were compared for their sensitivity in detecting PSTV, with Nick-translated and method B probes being the least sensitive.
Abstract: 32P-labelled probes prepared by nick-translation, two methods (A and B) of labelling PSTV cDNA in M13 phage DNA, and RNA transcription were compared for their sensitivity in detecting PSTV. Nick-translated and method B probes were the least sensitive. The minimum concentration of PSTV detected by these probes was 100 pg. Method A probe detected 10–20 pg of PSTV whereas RNA transcripts were capable of detecting as little as 0.33 pg of PSTV. RNA transcripts are easy to prepare, and their use in hybridization analysis do not cause background reactions. Sometimes low non-specific signals are produced but they can be eliminated by washing membranes with RNase A. RNA probes are now used for routine detection of PSTV in tuber flesh and sprouts, leaves and true seed of potato at the International Potato Center (CIP).
25 citations
TL;DR: In general, almost all programs have experienced difficulties of virus infections and/or other diseases in the cutting operations, and a careful and systematic testing program must be developed with micro-propagation methods to correct these problems.
Abstract: In general, almost all programs have experienced difficulties of virus infections and/or other diseases in the cutting operations. A careful and systematic testing program must be developed with micro-propagation methods. More production ofin vitro plantlets and cuttings is usually needed in the early years of a program than is needed later. The re-use of non-certified seed derived from high quality certified seed eventually reduces the demand for certified seed. Over production of cuttings is not an uncommon occurrence as a seed program matures. High quality seed does not always result in higher yields of ware potatoes. An economic analysis of the system should be initiated early in the development of a program. Studies on seed marketing and demand are usually beneficial to the proper planning and executing of a seed production program. In vitro propagation and rapid multiplication of pathogen-tested cultivars are fast becoming an important factor in developing self-sufficiency in seed potato production in Third World countries. The reduced number of field generations needed to supply sufficient quantities of quality seed is becoming a reality in countries where climatic and economic constraints are limiting.
Journal Article•
TL;DR: In this paper, the future prospects of the sweet potato as a food, a livestock feed, and a raw material for industry are investigated and the causes underlying these trends are investigated.
Abstract: Nearly all sweet potatoes are grown in developing countries, about 80% in China alone. Since the early 1960's, sweet potato production has fallen sharply in developed countries. It has increased modestly in most developing areas, significantly so in Africa. Interdisciplinary field studies are needed to determine the causes underlying these trends and the future prospects of the sweet potato as a food, a livestock feed and a raw material for industry.
TL;DR: The results show the potential of using cuttings in commercial growing of potatoes in the warm tropics where tuber seed is difficult to obtain and maintain.
Abstract: Growing potatoes from cuttings for seed and table potato production has great potential in Asia. There is limited information available explaining the agronomic methodology of growing cuttings in the field. This research was conducted to assess the importance of 4 management variables on the growth and tuber yield of cuttings. Three planting systems were evaluated with and without hilling. Only hilling significantly improved yields and increased tuber number per plant by 50%. Hilling also reduced tuber greening. Increasing plant population from 40,000 to 100,000 per hectare resulted in a yield increase of at least 50%, however average tuber size decreased. Pruning of the apical shoot at or after transplanting did not improve branching, canopy cover or tuber yield. Yields from cuttings were equal to or greater than the tuber seed grown control treatments. Yields ranged from 15 to 20 t/ha which is acceptable for the warm growing conditions. These results show the potential of using cuttings in commercial growing of potatoes in the warm tropics where tuber seed is difficult to obtain and maintain.
TL;DR: Nine experiments were run at three hot tropical sites within Peru to quantify the influence of plant population on soil temperature and growth and yield of the potato, finding tuber yield increased linearly with increases in planted population over the range studied, and was proportional to increases in the amount of intercepted radiation.
TL;DR: Seven wild diploid potato species, Series Tuberosa, representing 1023 clones were screened for resistance to the potato cyst nematode, Globodera pallida, and high frequencies of resistance to P4A and P5A were found in progenies of these and other resistant species with cultivated potatoes.
Abstract: Seven wild diploid potato species, Series Tuberosa, representing 1023 clones were screened for resistance to the potato cyst nematode, Globodera pallida. Over 25% of the clones were resistant to pathotype P4A and almost 30% were resistant to pathotype P5A. The resistance in hybrid progenies of these and other resistant species with cultivated potatoes was evaluated, and over 2200 seedlings were screened. High frequencies of resistance (>50%) to P4A were found in progenies with Solanum leptophyes, S. vernei, S. gourlayi and S. capsicibaccatum, whereas resistance to P5A was found in these species as well as S. sparsipilum. The importance of nematode resistant wild species for potato breeding is discussed.
01 Jan 1988
TL;DR: An attempt has here been made to picture the global effects of filamentous viruses by asking authorities in different world regions to assemble a hit parade of their 10 favorite viruses—favorite in the sense that a true pathologist always relishes a good, destructive disease.
Abstract: An attempt has here been made to picture the global effects of filamentous viruses by asking authorities in different world regions to assemble a hit parade of their 10 favorite viruses—favorite in the sense that a true pathologist always relishes a good, destructive disease.
TL;DR: Nine 2x clones with different genetic backgrounds and 2n pollen production by first division restitution (FDR) were each mated with five 4x females in a linextester design, illustrating the importance of progeny testing for FDR clones before their utilization as progenitors.
Abstract: Nine 2x clones with different genetic backgrounds and 2n pollen production by first division restitution (FDR) were each mated with five 4x females in a linextester design. Estimates of both general combining ability (GCA) and specific combining ability (SCA) were significant for tuber yield, among female and male parents. Four FDR clones with similar genetic background (half-sibs) showed significantly different GCA for total yield, illustrating the importance of progeny testing for FDR clones before their utilization as progenitors. A stronger influence of the 2x parents, compared to that of the 4x parents, on the performance of the hybrids was observed for characters studied. The significance of male and female interactions for characters other than tuber yield reinforced the importance of careful choice of the male and female parents for improving horticultural traits of 4x–2x progenies.
TL;DR: The use of True Potato Seed (TPS) was considered as an alternative planting material because it can be stored for eight months with low storage losses and when replanted give substantially higher yields than those obtained from locally grown, degenerated seed tubers.
Abstract: Quality tuber planting material is unavailable in the Red River Delta (RRD). The use of True Potato Seed (TPS) was considered as an alternative planting material. During the 1985–86 and 1986–87 seasons, 21 and 40 kilos of open pollinated TPS, respectively, were collected in the southern highlands and distributed to over 40 cooperative groups of farmers in the RRD. Fifty-two hectares (1985-86) and 120 hectares (1986-87) of potatoes were produced from transplants in the two years of on-farm production. Approximately 50% of the farmers were successful in both years. Lack of experience and too wet or too dry growing conditions caused most of the failures. Yields from transplants ranged from 5 to 13 t/ha with 150 to 300 seedling tubers/m2. Seedling tubers can be stored for eight months with low storage losses and when replanted give substantially higher yields than those obtained from locally grown, degenerated seed tubers.
TL;DR: The high rates of successful doubling from many genetically different clones, demonstrates the applicability of this method as a means to convert valuable 2x potato germplasm into the 4x level.
Abstract: Twelve 2x potato clones of diverse genetic origin were tested for doubling of their chromosome number by placing stem and petiole segments in the regeneration medium (Hermsen et al., 1981). Eleven of the 12 clones yielded doubled plants (2n=4x=48). The percentages of regenerated tetraploid plants varied from 0 to 77% among the genotypes tested. The high rates of successful doubling from many genetically different clones, demonstrates the applicability of this method as a means to convert valuable 2x potato germplasm into the 4x level.
TL;DR: Superior clones have been identified which could further enhance yield and increase the area of lowland potato production by identifying a combination of field resistance to viruses, long dormancy and good storability.
TL;DR: Of the three aphid strains, those from Minnesota had the lowest susceptibility to permethrin, pirimicarb and azinophos-methyl, and no mortality was observed in this GPA strain when tested with azinphosmethyl.
TL;DR: Results show minimum ait temperatures above 21 °C are unsuitable for potato production, and highland seed is an alternative for poor farmers.
TL;DR: Results suggest an optimal combination of storage method, cultivar choice, and sprout management practices may be achieved to obviate the need for cold storage in warm climates.
Abstract: Seed tubers of four cultivars were grown under similar conditions and harvested simulataneously. They were stored in traditional dark storage, diffused-light storage, or cold storage, and with combinations of these three methods for 150 or 230 days beginning in the hot, dry summer period. The effect of storage conditions on emergence, stem and tuber number, tuber size distribution and yield is discussed. Results suggest an optimal combination of storage method, cultivar choice, and sprout management practices may be achieved to obviate the need for cold storage in warm climates. Emergence and yield were consistently good for the 150-day storage period when traditional storage was followed by diffused-light storage. The sam technology gave promising results for the 230-day period with cultivars Claustar or Desiree when seed was desprouted prior to planting.
TL;DR: In this article, the effect of desprouting on potato crop yields was investigated in two experiments at Glasgow, Scotland, where seed tubers of four potato cultivars were stored at a range of temperatures in darkness and artificial light.
Abstract: SUMMARY
In an experiment with eight potato cultivars at Huancayo, Peru, storage of seed tubers in a prototype diffuse-daylight store resulted in a mean 17% increase in the yield of the subsequent crop, and in more rapid emergence of six of the cultivars after planting, as compared with seed stored in darkness. The dark-stored seed had very long sprouts that had to be removed at planting.
In two experiments at Glasgow, Scotland, seed tubers of four cultivars were stored at a range of temperatures in darkness and artificial light. At the time of planting, some of the light-stored tubers were desprouted as well as the dark-stored ones, so that the effect of desprouting could be distinguished from any direct effect of storage in darkness. Desprouting consistently delayed emergence and senescence of the crop and in most cases reduced its yield. In 1983 the yield reduction was greatest in the first early cV. Home Guard after storage at high temperature (22 °C), when it was associated with low stem numbers and incomplete emergence. In 1984 after light storage at still higher temperature (22/33 °C) and desprouting, this cV. behaved similarly, but the corresponding dark-stored treatment yielded heavily after greatly delayed haulm senescence. CV. Desiree and, in 1984, cV. King Edward retained some apical dominance after storage at the lower temperatures and in some cases responded to desprouting with a small yield increase.
In general desprouting after high-temperature storage reduced yields more than could readily be explained on the basis of the physiological age being reset to zero at planting.
01 Jan 1988
TL;DR: These studies indicate that, in natural populations and in cultivars, pollen competition can be used to select for increased vigor and for increased stress tolerance, the subject of this article.
Abstract: A series of studies has indicated that 60 75% of the structural genes which are expressed in the sporophyte of both angiosperms and gymnosperms are expressed, and thus subject to selection, also in the pollen (see ottaviano and Mulcahy, in press, for review). The consequences of this overlap between sporophytic and gametophytic genomes were first indicated by Ter-Avanesian (1949, 1978), later by others (see ottaviano and Mulcahy, in press), and more recently by Winsor, et al. 1987). Although the first studies of pollen selection have been conducted with cultivated plants, because of the technical advantages that these provide, the efficacy of pollen selection is not limited to cultivars. In Aureolaria flava (Scrophulariaceae), seedlings from the highest level of pollen tube competition in natural populations exhibited significantly larger rosettes and were more likely to produce flowering stems in the first season than were seedlings produced with little or no pollen tube competition (Ramstetter and Mulcahy, in prep.) These studies indicate that, in natural populations and in cultivars, pollen competition can be used to select for increased vigor (see ottaviano, this volume) and for increased stress tolerance, the subject of this article.
TL;DR: For breeders the observed variability does not seem useful in a screening program based on morphological traits using controlled environment instead of field conditions, and under controlled conditions highly significant differences among the HT clones were found.
TL;DR: Wild diploids in Series Tuberosa crossed easily with cultivated diploid species, except with Solanum lignicaule where most pollinations failed, and seed set was extremely low, it is suggested that this species is 1EBN.
Abstract: Over 2400 pollinations were made to investigate the crossability relationships between cultivated potatoes, and wild diploid species from Series Tuberosa and Circaeifolia, as well as wild polyploid species in Series Tuberosa and Longipedicellata resistant to potato cyst nematode, Globodera pallida pathotypes P4A and P5A. Wild diploids in Series Tuberosa crossed easily with cultivated diploid species, except with Solanum lignicaule where most pollinations failed, and seed set was extremely low (0.2 seeds per pollination or less). It is suggested that this species is 1EBN. S. capsicibaccatum is clearly isolated from Series Tuberosa, but can form hybrids with S. lignicaule, which can act as a bridging species to S. tuberosum haploids. S. gourlayi and S. oplocense can be crossed with both subspecies of S. tuberosum, but S. papita, Series Longipedicellata is reproductively isolated from the tetraploid cultigens. The crossability data are discussed in the light of germplasm utilisation for breeding potato varieties resistant to potato cyst nematode.
TL;DR: Elimination of weak plants during population thinning and subsequent interplant competition significantly reduced the frequency of inbred plants.
Abstract: The effect of selection against weak plants was studied in artificial mixtures of hybrid (S0), first self-pollinated generation (S1), and second self-pollinated generation (S2), true potato seed. Selection of vigorous seedlings in true seed populations raised in flats from mixtures of S0 (25%), S1 (50%), and S2 (25%) seed increased the frequency of hybrids to 71%. In another study, two mixtures of S0 and S1 seed (1∶3 and 1∶1) were densely sown in beds to produce seedling tubers. Elimination of weak plants during population thinning and subsequent interplant competition significantly reduced the frequency of inbred plants. The resulting seedling tuber progenies were planted in the field and mean yields from the two mixtures of S0 and S1 seed were 96% and 99% of related completely hybrid progenies. The implications of these results for TPS production are discussed.
TL;DR: An early maturing progeny with resistance to BW is needed to permit a more rapid spread of this technology and to avoid Pseudomonas solanacearum.
Abstract: Potato production using true potato seed (TPS) was evaluated with a cooperative group of farmers. The cooperative grew TPS or seed tubers (1 to 3 g) produced from TPS in beds in screenhouses to avoidPseudomonas solanacearum (BW). From 250 to 400 tubers/m2 were obtained. Tubers > 3 g were replanted by farmers at high elevation for further multiplication. Yields always exceeded the control (clonally produced cultivar). Seed tubers from TPS of 3 to 5 g produced up to 32 t/ha resulting in a multiplication rate of 145:1. Farmers are in various stages of adopting this technology. An early maturing progeny with resistance to BW is needed to permit a more rapid spread of this technology.
01 Jan 1988
TL;DR: Since the most important viruses in potato are not passed on through sexual seeds, 1PS may be used to produce potatoes for consumption or for the production of clean “seedling tubers.”
Abstract: In the last ten years, scientists at the International Potato Center (CIP) have been investigating the potential of true potato seed (TPS) as an alternative to traditional potato production from tuber seed in developing countries. The potato is considered a luxury vegetable in many developing countries. Locally produced seed tubers are often of low quality and certified seed is usually imported at high cost from countries with temperate climates. The production of healthy seed tubers in tropical areas is difficult because warmer temperatures are conducive to higher levels of potato pathogens of which viruses are of high importance. Since the most important viruses in potato are not passed on through sexual seeds, 1PS may be used to produce potatoes for consumption or for the production of clean “seedling tubers.”