This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

The physiological development of potato plants and tubers grown in Arizona desert regions were examined and spectrophotometric methods were developed for the analysis of carbohydrates in potato tubers, pollen, and leaf tissues from various plants. Seed pieces were planted (March 1979, 1980) and harvested (June, July) in 2 locations. Emergence, tuber initiation, and maximum tuber numbers occurred 3, 5, and 10 weeks, respectively, after planting. In 1979, tuber yields in Mesa were low because of a shortened growing season; in Tucson, yields were drastically reduced because of soil water-logging. In 1980, tubers were planted in Mesa (March 5) and yield of the cultivar 'Kennebec' was higher, 'Denali' was nearly equal to whereas 'Norgold Russet' was lower than the national average for the respective cultivars. 'Kennebec' had the highest leaf area index (LAI) and plant height. Plantings in Marana (March 21) had lower LAI and plant height than in Mesa and yielded less, but rankings of cultivars for yield were the same. During rapid tuber growth, air temperatures often exceeded 40°C, but lower canopy temperatures were 30°C or lower, and water potentials (ψ) were -9 bars or higher. Chemical analysis showed tubers increased starch percentages during development, and levels at maturity were similar to those found in other regions of the country. Extracts for carbohydrate analysis were obtained by overnight immersion in 80% ethanol and total soluble sugars (TSS) were analyzed by an improved anthrone assay and also with para-hydroxybenzoic acid hydrazide (p-HBAH) following methylation and permanganate oxidation. Methods were also developed for estimating total keto sugars with phenol in acetic/sulfuric acid (PASA) and also with thiobarbituric acid (TBA). Aldohexoses were determined with o-toluidine and o-ethylaniline; total reducing sugars were analyzed with p-HBAH, and sucrose was estimated with anthrone or PASA or TBA following alkaline enolization or borohydride reduction of monosaccharides. Starch was determined quantitatively after enzymatic hydrolysis to glucose and analyzing with anthrone, o-toluidine, or p-HBAH. Potential errors involved in the methods are discussed and the techniques were applied to carbohydrate analysis in plant tissues and pollen.

No description available.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

During the past several years considerable experimenting has been aimed at developing methods for improving potato yields. One of the easiest and most effective ways found was to adjust the seed piece size and number of eyes per piece. Seed pieces were cut to meet the following size categories: 1/2, 1, 1-1/2, and 2 ounces and small whole tubers; 1-1/2, 2 and 2-3 ounces. Significant differences in yield were obtained between the various seed piece size treatments. The yield advantage was in favor of the larger size. The number of eyes per piece was less important except with the smallest size. In this case the seed pieces were incapable of adequately supplying plant growth from more than one eye. Small, whole tubers from good high yielding fields were found to be excellent for seed potato pieces.

The importance of proper fertilizer placement has been demonstrated in recent greenhouse studies. Small, seemingly unimportant changes in fertilizer placement often in reality are very important. Specially constructed boxes with glass fronts were used to study root development as affected by fertilizer placement. Yields were significantly different one from another with the poorer ones resulting where fertilizers were placed too close to the seed piece. Yields ranging from 298 cwt, where the fertilizer was placed two inches to each side and level with the seed piece; up to 367 cwt where the fertilizer was placed four inches to each side and two inches below the seed piece. Root burning and speed of root regeneration represent the most important consideration to be reckoned within the proper placement of fertilizer.

Data from five years of experimentation with irrigation and soil moisture levels indicate that a certain knowledge and general understanding of these factors is important in potato production. Nine treatments ranging from a constant very wet level to a constant dry treatment were used. Yield differences were significant and varied from a low of 321 cwt, from plants exposed to a very wet (18-20 centibars tension) level early in the season followed by a dry (75-80 centibars tension) condition during the last part of the growing season, to 416 cwt where the plants were kept at a dry level early and changed to a very wet level late in the season. Growers often unknowingly reduce yields and lower quality by applying excessive amounts of irrigation water.

No description available.

Ten percent granular formulations of phorate and Di-Syston at 20 pounds per acre will effectively control psyllids, aphids and thrips on potatoes. Two years study varying the placement of granular systemic insecticides in the soil in relation to the seed piece has not produced any significant differences in the insect control. The yields from plots in which the granules were placed four inches to the side and two inches below the seed piece were greater. All were better than the untreated check. Of two new systemic insecticides applied as granules at planting time, the material US-21149 (Temik R) gave outstanding insect control and above average yields on Kennebec variety potatoes. Compound NIA-10242 gave less effective insect control and yields below UC-21149.

Isolates of Verticillium Albo-atrum were obtained from potato and from cotton. Investigations are in process to ascertain the relationship between cotton Verticillium wilt and potato Verticillium wilt and to determine the significance of the disease to Arizona potato production.