Fructans are polyfructose molecules that function as nonstructural storage carbohydrates in several plant species that are important crops. We have been studying plants for their ability to synthesize and degrade fructans to determine if this ability is advantageous. We have also been analyzing the ability to synthesize fructan in relation to other nonstructural carbohydrate storage forms like ...

A viroid was isolated from Iresine herbstii plants using the bidirectional PAGE method for analysis of small circular RNA molecules. The viroid was transmitted to viroid-free Iresine herbstii plants of the cultivar 'Aureoreticulata' by mechanical inoculation. Infected plants did not develop any symptoms. The new viroid species has been named Iresine viroid (IrVd). It is a member of the potato s...

The use of in vitro potato shoot cultures for protoplast isolation is desirable for consistent protoplast qualities. Ethylene build-up in the culture vessels causes problems for leaf growth (e.g. decreasing leaf surface, dry weight and chlorophyll) in shoot culture. Fifty to one hundred µM Silver thiosulfate (STS) produced a larger leaf area as a source of plant material for protoplast isolatio...

A reliable method to eliminate tobacco rattle virus (TRV) from viruliferous Paratrichodorus allius populations was developed. This virus is vectored by P. allius in the Pacific Northwest and causes corky ringspot disease (CRS) of potato. The viruliferous nematodes that were reared on 'Vernema' alfalfa or '770' scotch spearmint for at least 3 months did not transmit TRV to 'Samsun NN' tobacco, a...

Some potato species require a short-day (SD) photoperiod for tuberization, a process that is negatively affected by gibberellins (GAs). Here we report the isolation of StGA3ox2, a gene encoding a GA 3-oxidase, whose expression is increased in the aerial parts and is repressed in the stolons after transfer of photoperiod-dependent potato plants to SD conditions. Over-expression of StGA3ox2 under...

Petroleum-oil sprays and fogs are used increasingly to control insect pests of economic plants. These oils are useful in controlling the aphid vectors of potato virus, but it is first necessary to learn which oils are tolerated by potato leaves. Hence, undiluted oils and cresoap emulsions of petroleum oils were tested on potato leaves to determine: (1) The rates of oil penetration into leaves; ...

The Colorado potato beetle had Gary Felton stumped. Felton, an entomologist at Pennsylvania State University, has built his career on revealing how plants defend themselves against voracious insects. Plants often detect chemicals in an insect’s oral secretions and respond by producing proteins that wreak havoc on insect digestion and nutrient absorption. But the Colorado potato beetle was diffe...

The effect of temperature on the rate of systemic infection of potatoes (Solanum tuberosum L. cv. Chu-Baek) by Potato virus Y (PVY) was studied in growth chambers. Systemic infection of PVY was observed only within the temperature range of 16°C to 32°C. Within this temperature range, the time required for a plant to become infected systemically decreased from 14 days at 20°C to 5.7 days at 28°C...

Genetic engineering is recognized as a powerful tool for altering the genetic characteristic of crop plants. Genetic engineering has tremendous potential in developing improved potato varieties with desired agronomic traits and has been utilized for improvement of several crop plants including potato to enhance essential amino acid, protein and lipids/carbohydrates contents as well to improve s...

BACKGROUND The potato psyllid is a serious pest of potatoes. Sampling plans on potatoes for the potato psyllid have yet to be developed, thus the authors' objectives were (1) to determine the most efficient within-plant sampling unit, (2) to determine the spatial dispersion of potato psyllids in potato fields and (3) to develop a binomial sequential sampling plan for this pest. RESULTS Signif...