The common potato pollen collector modified for bulk pollen collection

When considerable amounts of pollen must be collected, the conventional buzzer and capsule become cumbersome and inefficient. Described is a modified device that can make bulk polien collection easier and more efficient.     

An effective method for culturing pollen tubes of potato

In vitro culture of pollen tubes is a convenient way to distinguish inviable pollen from stylar incompatibilities which prevent pollen tube growthin vivo. This usefulness ofin vitro pollen tube culture depends on how successful the technique is in promoting optimal pollen tube growth. Experiments were conducted to compare the effects of the type of sugar and method of aeration of cultures ofSolanum species (potato) pollen. Lactose was superior to sucrose in promoting pollen germination and pollen tube growth on hanging drop cultures. Germination and growth were greatly enhanced when pollen was cultured in actively aerated lactose medium. Since pollen growth comparable to that occurringin vivo was observed using lactose medium with active aeration, this technique may be useful in various types of research related to reproductive biology.     

A bulk potato trailer for research plots

A bulk trailer was designed and evaluated which facilitates the handling of potatoes from field plots to storage. To meet the requirements of harvesting field plots, the trailer was designed to accommodate both manual and mechanical harvesting. Design techniques, such as incorporating framing members into the shape of the bulk body, were utilized in order to develop a low profile trailer. This was also made possible by the use of cantilevered tandem axles. The resulting trailer had a loading height at either 1270 or 1575 mm with a maximum capacity of 6 tonnes. Tests which were conducted to measure the mechanical injury caused to the potatoes indicated that the average damage index was 166.2 which included both the harvesting and transportation.     

Partial collection of data on potato yield for experimental planning

The aim of this study was to estimate the number of blank experiments (BE) (i.e., a uniformity trial) required to estimate the optimum plot size for use in experiments involving potato crops. The study was based on data on the mass of potato tubers (Solanum tuberosum L.) from 3456 hills (i.e., 24 rows of 144 hills each) obtained from a BE. Using these data, BE of different sizes (i.e., 2 rows of 24, 36, 48 and 72 hills) were planned to estimate optimum plot size. For each BE, 11 plot sizes (X) were planned based on the sum of adjacent hills, and the mean, variance and coefficient of variation (CV) between plots of the same size were calculated. Regression models for CV were adjusted in terms of X to estimate the optimum plot size. For each BE size, a bootstrap resampling method was used to estimate the sufficient number of BE to enable precise estimates of optimum plot size, mean and other statistics. It was found that a sampling potato hill yield of 39% of subdivisions within an experimental area where a potato experiment is to be performed is sufficient to estimate optimum plot size for the experiment. Plots composed of one row of six hills are sufficient to estimate potato yield.     

Cytology of potato triploids producing 2N pollen

Parallel spindles (ps) were found in a spontaneously occurring triploid plant ofS. chacoense and two triploids ofS. commersonii. This may be the basis for the formation of plump, stainable pollen in these triploids, since ps at Ana II could confer male fertility to odd-ploids by forming pollen with the 2n chromosome number. The participation of 2n gametes in the origin and evolution of polyploidsolanum via sexual polyploidization is strongly implicated.     

Screening the U.S. potato collection for frost hardiness

Potato is one of the most important world vegetables with respect to value of production and nutritional impact. Frost susceptibility reduces or precludes production on millions of hectares worldwide. In contrast to disease and pest problems, cultural or chemical treatments are not likely to be helpful in combating frost, so genetic improvement must be sought. Fortunately, wild relatives of the cultivated potato have been shown to exhibit frost tolerance far superior to that of cultivated species. In this research, over 2,600 accessions representing 101 species in the US potato collection at Sturgeon Bay, Wisconsin were visually screened after natural frosts in a uniform field in 1992. This provided a more comprehensive survey of germplasm accessions, further characterized species’ hardiness and intraspecific variation. The most hardy species wereSolanum acaule, S. albicans, S. commersonii, andS. demissum. An additional previously unreported extremely frost hardy species (Solanum paucissectum) was discovered. This information should expand the insights and germplasm options available to those intent on breeding desirable varieties with high levels of frost hardiness.     

Use of single-leaf cuttings of potato for efficient mass propagation

Summary Potato stock plants of five commercially propagated varieties, which derived from tissue culture, were grown at a low light irradiance in non-aseptic conditions. The plants produced tiny-leaved etiolated stems, which were a good source of cuttings for further propagation. The method was tested by growing micropropagated and cutting propagated plants as three lines of stock plants, based on different clonal generations, and which were repeatedly harvested for cuttings. There was wide variation in the multiplication capacity among the varieties used. The most productive variety produced more cloned potato plants than when micropropagated in vitro. Stock plants derived from single-leaf cuttings produced more new cuttings than when derived from tissue culture. The growing facilities used were simple and inexpensive and could be set up anywhere. The method is economically competitive due to the need of only very simple and inexpensive growing rooms, and would be worth using particularly in developing countries and also in advanced potato production. All the cuttings of different harvests rooted well and the last propagated cuttings of the lines were still free of prevalent viruses although using simple growing facilities.     

Seed set with potato pollen stored at low temperatures

Pollen from several tuber-bearingSolarium species was exposed to liquid nitrogen (LN₂) and tested forin vitro germination and seed set capabilities. Pollen placed in LN₂ or in the vapor phase above LN₂ retained high levels ofin vitro germination after 11 to 24 months of storage. This pollen also set significant numbers of seed. Brief drying of the pollen over anhydrous CaCl₂ prior to freezing increased survival in most samples. Rehydration of dried, LN₂ treated pollen prior toin vitro germination testing was necessary to obtain maximum germination percentages. Rehydration, however, was not necessary for seed set, and in several samples decreased seed set compared to pollen that was not rehydrated. Storage of pollen from tuber-bearingSolanum species in LN₂ appears to be practical for maintaining pollen for crossing and for germplasm preservation.     

A new procedure for the mass extraction and collection of potato glycoalkaloids

A methodology for the collection of large volumes of potato glycoalkaloids from potato blossoms has been developed for use in preparative work. This new modification shortens and simplifies the laborious proceduresutilized heretofore and should prove a valuable aid for those requiring multiple gram quantities of pure glycoalkaloids for use in further research.     

Advantages of storage of potato pollen in liquid nitrogen

Summary Potato pollen stored in liquid nitrogen (−196 C) showed no significant decrease in percentage germination after nine months, whereas pollen stored at −20 C showed a decrease in germination to <1% over the same period.     

An agenda for future potato research

Summary The world is changing, and the rate of change is accelerating, nowhere moreso than in the pace of scientific discovery and the advance of technology. The last thirty years have also seen substantial global changes in potato production which are likely to continue if current projections are correct. Climate change is bound to affect local weather patterns, which will influence both the epidemiology of pests and pathogens and broaden their geographic range. An agenda for future research will of necessity include much of the current agenda; research into more sustainable systems; research into new and novel resistances to biotic and abiotic constraints, combining modern cell and molecular-based technologies with classical breeding approaches and research into the genetic and biochemical bases of low temperature sweetening and dormancy control, that should lead to varieties with superior storage characteristics, particularly for processing. However, a future agenda has to retain some flexibility and a component of speculative research. Perhaps potatoes could become a source of industrial feedstock or pharmaceuticals, perhaps there is a place for cultivars produced by botanic seed in Europe? The exciting thing about research is that we cannot always predict where it will lead, and a future agenda must not curb the enthusiasm of any young scientist by too rigidly adhering to that suggested here. it is essential that scientific options are kept open.     

The incidence of potato viruses X,Y and S in the Chilota potato collection

The 530 potato clones of the Chilota collection of the germplasm bank from the Universidad Austral de Chile were tested for potato viruses X (PVX), Y (PVY) and S (PVS) by means of NCM-ELISA (nitrocellulose membrane enzyme-linked immunosorbent assay). Four clones (0.8%) healthy for all 3 viruses simultaneously were detected. These clones could be resistant to the above mentioned viruses.     

Screening tuber-bearingSolanum (potato) germplasm for efficient accumulation of tuber calcium

Resistance to several pathological and physiological tuber defects has been correlated with calcium level in the peel. In this study, a representative sample of potato species (including cultivated), was grown in the greenhouse. Plants were watered with low and high calcium solutions, and the resulting tubers analyzed. Thus, potato germplasm was screened for ability to accumulate tuber calcium when a control level of calcium is available, and ability to respond when higher levels are supplied. Some wild species significantly exceeded cultivated materials in one or both of these measures. Such species may provide a resource for breeding varieties which are more efficient calcium accumulators.     

Spindle tuber virus in seeds and pollen of infected potato plants

The presence of potato spindle tuber virus (PSTV) in seed and pollen of diseased plants was demonstrated. Transmission through the seed from open-pollinated female parents to the seedlings occurred frequently (average 31%) but varied in individual collections from zero to 100%. The amount of transmission did not appear to be correlated with variety or with age of the seed. All PSTV infections encountered appeared to be caused by mild strains. It is suggested that only healthy parents should be used for breeding purposes.