W. C. Edmundson

Response of several varieties of potatoes to different photoperiods

SummaryResults of the studies conducted with 9-, 11-, 13-, and 17-hour photoperiods in the greenhouse indicate that the different photoperiods have little effect on the diameter of the stems in the potato plants. There was, however, a significant difference in the height of the plants,—the tallest plants being produced with the longest light period. There was a highly significant difference in the number of bud clusters produced per plant by the 17-hour and all the remaining treatments. The different photoperiods had no effect on the percentage of fertile or stainable pollen. The plants in the 17-hour photoperiod produced the most buds for pollination and developed the most seed balls and the largest weight of both seed balls and seed.The results of the two-year studies indicate that varieties differ widely in their light requirements for flower and seed production. Some varieties produced an abundance of blossoms and seed with each of the light treatments; however, most varieties developed a larger number of blossoms and more seed with the longest photoperiod.

The Effect Of Psyllid Injury On The Vigor Of Seed Potatoes

P U B L I S H E D B Y THE POTATO ASSOCIATION OF AMERICA S O M E R V I L L E , N . J . N E W B R U N S W I C K , N. J . O F F I C E R S A N D E X E C U T I V E C O M M I T ~ E C. H. Mm~zom, P r e a i d ~ t . . . . . . . . . Colorado S t a t e C o l l e g e , F o r t C o l l i n s , C o l o r a d e F. M. BL0~WrT, V ~ c e P r e s t d ~ t . . . . . . . . . . . . Corne l l U n i v e r s i t y , I thaca , N e w Y o r k WM. H . ~ffJkRTIN, SeC.-TTSGS., J~(tOT..Agr. E x p . S ta . , N e w B r u n s w i c k , N e w J e r s e y 0 ~ SMZTH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C o r n e l l U n i v e r s i t y , I t h a c a , N e w Y o r k L. M. WAmz . . . . . . . . . . . . . . . . . . . . . . A l a b a m a A g r . E x p . S t a t i o n , A u b u r n , A l a b a m a R. A. . IBHL• . . . . . . . . . . . . . . . . . . U n i v e r s i t y of M a r y l a n d , C o l l e g e P a r k . M a r y l a n d A. H. E~DXNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A g r . E x p . S ta . , G a i n e s v l l l e , F l o r i d a

Comparison of Katahdin potato pollen produced in the field and in the greenhouse

Studies were conducted in the field and in the greenhouse at Greeley, Colorado, at an elevation of 4,800 feet and in the field at Estes Pa rk at an elevation of 7,500 feet in 1939 to determine the effect of growing conditions on the percentage of stainable pollen from well-advanced buds and from blossoms of the Katahdin potato. In most years the crosses made at Estes Park were quite successful, although in some years most of the crosses did not produce seed. Pollinations in the field at Greeley, however, have generally met with little success because of unfavorable climatic conditions. Although no accurate weather reports are available for Greeley, they are available for Denver, which is only 5 ° miles away and has an altitude of approxi-mately 5,2oo feet. According to the Weather Bureau report the average maximum temperature at Denver for July 1939 was 9o.2 ° F., and the average minimum temperature was 64°; for August the averages were 85 ° and 64 °. The average relative humidity for July at 5:3 ° a. m. was 53 per cent; at noon, 23 per cent; and at 5:3 ° Pm., 2o per cent; for August the readings were 62, 29, and 28 per cent, respectively. At Estes Park the temperature during the growing season is about lO ° to 15 ° lower than that at Greeley, and the relative humidity is somewhat higher. Previous studies with 9-, I I , I3-, and I7-hour photoperiods in the greenhouse indicated that the different photoperiods have no effect on the percentage of stainable pollen (1). In the present test the greenhouse plants were given a I6-hour photoperiod. In the field the photoperiod varied from approximately 15 hours at time of emergence to nearly 14 hours at the time the blossoms were gathered. A night temperature of 55 ° F. and a day temperature of 7 °° to 75 ° were maintained in the greenhouse, although the day temperature was higher for short periods in the afternoon. A humidity of 75 to 85 per cent was maintained by sprinkling the walks and soil under the benches. The humidity, however, would drop for short periods when the ventilators were opened to lower the temperature.

Seed-setting in potatoes as affected by spraying with a-naphthaleneacetamide and by light

SummarySpraying potato plants with dilute concentrations of a-naphthal-eneacetamide was not effective in increasing flower or seed ball production in the greenhouse at Beltsville Maryland, or Greeley, Colorado. Higher concentrations reduced flower production at Presque Isle, Maine.Sebago and Irish Cobbler produced more seed balls at Greeley than at Beltsville. Less cloudy weather at Greeley during the winter months is probably the chief factor responsible for this result.S 245–25, when self-pollinated, produced as many seed balls at Beltsville as at Greeley. It appears that this variety flowers and sets seed more readily under fairly unfavorable light conditions than either Sebago or Irish Cobbler.

Storage of potato seeds

Storage of potato seeds has little interdst for the grower who plants tubers or pieces of tubers to produce a crop; but the subject is of primary importance to the geneticist and other scientists who are trying to solve some of the growers" problems by breeding improved varieties of potatoes. The growing of seedlings from true seed is a necessary step in the origination of new varieties. It is of especial interest at present, since plans are being made to collect and maintain varieties and species of the potato, together with all the important crops, so that the most valuable genetic characters may be readily available to plant breeders. The potato germ plasm can be maintained in tubers or in true seed. Tubers must be grown every year but seed can be stored for a number of years. Clark 1 stored samples of a single lot of potato seed for 13 years under four different environments: in a heavy manila envelope at room temperature, ranging from 65 ° to 75 ° F. during the winter, and 85 ° to 90 ° or higher during the summer, and in tightly corked bottles at three temperatures: room, 40 ° and 32 ° . The seed in the envelope at room temperature was the first to lose its viability. At the end of 6 years only about 4 per cent of this seed germinated. The seed in the bottle at room temperature remained viable longer. It showed about 13 per cent germination after 10 years, but none the thirteenth year. After 11 years the seed in the bottle at 40 ° F. showed 84 per cent germination, but about 40 per cent the twelfth and thirteenth years. At 32 ° the seed maintained its viability throughout the 13-year period, showing 87 per cent germination at the end of that time. From 1912 to 1940 much of the surplus seed produced in the potatobreeding program of the United States Department of Agriculture was stored in coin envelopes at room temperatures. A study of the viability of this seed was made at the Plant Industry Station, Beltsville, Maryland, in the spring of 1950. Samples of seed produced each year from 1912 to 1940 were tested for germination, but only one sample (harvested in 1938) showed any signs of life, with only 30 per cent of the seed germinating. Since 1941 the surplus seed has been kept in coin envelopes in a refrigerator at approximately 34 ° F. Samples of seed harvested each year from 1941 to 1949 were planted May

Yampa, a new scab-resistant potato

SummaryThe Yampa potato has shown considerable promise as a scab-resistant, good-quality, high-yielding variety. It has shown field resistance to scab, early blight, and to leaf roll and mosaic. It appears best adapted to the lighter mineral soils. It has a relatively tough skin and keeps well. Maturity is approximately 7 to 10 days later than Irish Cobbler or Bliss Triumph.

Spraying and dusting potatoes with DDT and other materials

SummarySpraying and dusting experiments were made at Greeley, Colorado, in 1945 to test the effectiveness of DDT and other materials for the control of some potato insects and early blight.Psyllid populations were so low that no conclusions could be made regarding the relative effectiveness of the various treatments.Five pounds of basic copper arsenate in 100 gallons of 21/2-100 lime-sulfur solution, I pound of DDT in 100 gallons of water, 1 pound of DDT in 100 gallons of 6-x-100 bordeaux mixture, and 1 pound of DDT in 100 gallons of 1/2-100 Dithane solution all gave highly significant and equal control of the tuber flea beetle with regard to tuber injury.DDT appears to be compatible with both bordeaux mixture and Dithane.All the treatments were effective in reducing leaf injury caused by flea beetles, but the best control was obtained equally with basic copper arsenate in lime-sulfur, 1 pound of DDT in 100 gallons of water, 1 pound of DDT in 100 gallons of 6-x-100 bordeaux mixture, and 1 pound of DDT in 100 gallons of 1/2-100 Dithane.Three per cent DDT dusts, when applied at the rate of 25 pounds per acre, failed to control the tuber flea beetles.Both bordeaux mixture and Dithane reduced injury caused by early blight and gave increased yields as compared with the untreated plots.All treatments produced a highly significant reduction in the lygus population.All the DDT treatments significantly reduced the population of leafhoppers.

Osage: A new baking-type potato variety resistant to common scab

During the past few years there has been an increasing demand for potato varieties resistant to common scab, caused by Streptomyces scabies (Thaxt.) Waks. & Henrici). This disease has become a limiting factor in many areas of the country and is a particularly serious problem m some of the productive muck soils of the north-central states. Although resistance to scab has been a primary objective in potato breeding, the important features of yield, market quality, and cooking quality have not been neglected. The need is for a variety equal to Irish Cobbler in yield and cooking quality, but smoother, shallow-eyed and scab-resistant. ~Fhe new variety Osage is offered as an approach to this goal. It is a long potato, known commercially as a baking-type, or long-white. Tubers of Osage are smooth, shallow-eyed and uniform in type (Figure 1). In most localities Osage shows a high degree of resistance to scab.

Navajo and Blanca: Two new potato varieties resistant to scab and adapted to Colorado

SummaryNavajo (U.S.D.A. C.S. 13,178) and Blanca (U.S.D.A. C.S. 12,240) are high-yielding, medium-maturing, scab-resistant varieties adaptable to Colorado. Their tubers are smooth, white, and oval to round and slightly flattened. Tests have shown that they are equal to Katahdin in yielding ability and are usually superior in solids content. They are both good bakers. High-quality chips were made from their tubers after harvest and when reconditioned after storage.