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Bill B. Dean

Washington State Univ. Tri-Cities offers a new agricultural degree program titled Integrated Cropping Systems. It is intended to provide a basic education on the fundamentals of crop production and the environmental context in which crops are grown. Courses are offered at the upper division level to interface with the lower division courses offered at local community colleges. The curriculum is composed of courses in environmental science, ecology and conservation as well as crop growth and development, crop nutrition, plant pathology integrated pest management and others. Students need to meet the same requirements as those at other Washington State Univ. campuses in regards to the general education requirements. The purpose of the Integrated Cropping Systems program is to provide an educational opportunity for agricultural professionals and others in the region who are unable to commute or move to the main campus location. The curriculum provides the background needed for such occupations as grower/producer, crop scouting, sales representative and other entry level agricultural professions. It will supply credits toward certification through the American Registry of Certified Professional Agricultural Consultants (ARCPACS). Integrated Cropping Systems is a unique agricultural curriculum designed to help agriculturists integrate their production practices into the local ecosystem in a way that the environment does not incur damage. It emphasizes the use of environmentally conscience decisionmaking processes and sound resource ethics. The program will graduate individuals who have heightened awareness of the impact agricultural practices have on the ecosystem in which they are conducted.

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Bill B. Dean

Asparagus is a unique crop in that the yield of the crop is entirely dependent on the storage of carbohydrates from the previous season. The number of spears produced is determined by the number of buds on underground rhizomes and the size of each spear is related to the size of the bud from which it originates. Growth of spears begins in the spring when some minimal temperature is reached in the soil. We have determined that the minimum temperature for spear growth is 10°C (50°F) and that temperatures in excess of 35°C (95°F) inhibit growth. Using data from growth response to temperature experiments, we have compared the accumulative effects of hourly temperatures preceding harvest to subsequent yields. There was a significant effect of the number of hours above 10°C for the 24 hours preceding harvest and the yield obtained. Yield of spears cycled over an 11-day period which correlated to an eleven day weather cycle determined from the heat unit accumulations. Heat unit and yield cycles for seven cultivars over a 4-year period will be discussed.

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Gil Simmons and Bill B. Dean

Carrot (Daucus carota) L.) seed quality is affected by the environment in which it matures. Substantial differences in germination from year to year and from field to field have been recognized for many years for umbelliferae seed. Part of the explanation for low germination appears to be the harvest of immature seed. Data was collected for two years, from fields of the cultivars Chantenay and Nantes. Approximately 550 growing degree days were accumulated from anthesis until maturity for seed from the primary umbel. Growing degree days were calculated using a 10°C base temperature and without truncating for temperatures in excess of 35°C. Secondary, tertiary, and quaternary umbel seed maturity sequentially followed primary umbel seed. Secondary and tertiary umbels produced approximately 80 percent of the total seed yield while the primary and quaternary umbels produced approximately 20 percent. Seed maturity was determined by measuring the germination rate. Immature seed germinate at a slower rate than mature seed. The implications of these results for obtaining high quality carrot seed will be discussed.

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Bhimanagouda S. Patil and Bill B. Dean

Twenty-four genotypes of `Walla Walla' sweet onion (Allium cepa L.) grown in two locations were evaluated for several characteristics associated with bulb flavor and storage losses. The range of pyruvic acid content in bulbs stored (at 5C and 65–75% RH) for 0, 2, and 4 months were 3.4–7.54, 3.48–18.81, and 3.92–12.61 (μmol·g–1), respectively, among different genotypes. Bulb quality of several genotypes decreased during storage, as indicated by lower total sugar concentration (fructose, glucose, and sucrose) and greater pungency. At 5C after 4 months of storage, the range of marketable bulbs (percent by weight) was 31% to 89% among genotypes; however, at 15C, only two genotypes survived with 60% marketable bulbs. Pungency and sweetness changed independently during storage. Pyruvic acid was not correlated (r = 0.038) with the percentage of marketable bulbs remaining after 4 months of storage. In comparison with the short-day sweet onions (`Vidalia' and `Texas Grano 1015Y), `Walla Walla' sweet onions showed two-fold higher sugar: pungency ratio among genotypes.

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Bill B. Dean and Eugene M. Kupferman

Shelf life of perishable commodities is a function of time by temperature effects on the composite kinetic reactions within each commodity. Empirical tests to approximate shelf life have limited value, particularly in long-distance shipment when less than ideal storage conditions occur, such as for the export market. Time temperature monitors (TTMs) have been developed for monitoring storage temperatures and predicting remaining shelf life. Kinetics curves for ripening of pears, yellow color development in broccoli and browning of mushrooms were compared to kinetics properties of available TTMs at 5, 10, and 20°C. Each commodity deteriorated or ripened at rates corresponding to a different TTM. At 20°C, broccoli kinetics were similar to TTM MC 60 or 67, pears to MC 74, and mushrooms MC 66. Customized TTMs and application of this technology will be discussed.

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Bill B. Dean and Eugene M. Kupferman

Shelf life of perishable commodities is a function of time by temperature effects on the composite kinetic reactions within each commodity. Empirical tests to approximate shelf life have limited value, particularly in long-distance shipment when less than ideal storage conditions occur, such as for the export market. Time temperature monitors (TTMs) have been developed for monitoring storage temperatures and predicting remaining shelf life. Kinetics curves for ripening of pears, yellow color development in broccoli and browning of mushrooms were compared to kinetics properties of available TTMs at 5, 10, and 20°C. Each commodity deteriorated or ripened at rates corresponding to a different TTM. At 20°C, broccoli kinetics were similar to TTM MC 60 or 67, pears to MC 74, and mushrooms MC 66. Customized TTMs and application of this technology will be discussed.

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Bhimanagouda S. Patil and Bill B. Dean

Fall onions, grown for their long shelf life, have become popular both in domestic and export market. Sixty cultivars of onion from 14 major seed companies were grown in Quincy, Wash., and were analyzed for their flavor, quality, and anticarcinogenic flavonol, quercetin. The highest quercetin concentration (in mg·kg–1 fresh weight) was observed in the red onion `Feugo' (495.6) followed by `Tango' (396.8), while the least amount was in the yellow onion `Pinnacle'(152.5). The pyruvic acid content varied from 1.5 to 18.7 mmol·g–1 and total sugar (glucose, fructose, and sucrose) levels ranged from 9.4 to 36.9 mg·g–1 fresh weight among different cultivars. The ratio of sugar:pyruvic acid showed marked variation (1.6 to 64.00) among different cultivars. The variation in oligosacharides were ≈60-fold over all cultivars. The maximum degree of polymerization (DP) observed was DP8. We conclude that there is a potential for developing a mild onion for longer shelf life and better health properties. Yield at harvest and storage performance based on rot also was evaluated during storage.

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Bhimanagouda S. Patil and Bill B. Dean

Sweet onions have gained global importance because of their mild flavor and tear-free properties. A field investigation with seventeen Walla Walla Sweet onion entries grown at the IAREC of Washington State Univ. were evaluated in 1994 and 1995. The flavor and quality characteristics such as pyruvic acid and total sugar (fructose, glucose, and sucrose) concentrations were analyzed by spectroscopy and HPLC respectively. The pyruvic acid concentration in bulbs stored (5 °C and 65% to 75 % relative humidity) for 0, 2, and 4 months increased as the storage time increased. During 1994 and 1995 the pyruvic acid ranges during storage were 4.8 to 7.9 and 2.9 to 9.6 mmols·g–1, respectively. Total sugar concentration in 1994 decreased as the storage period increased, while in 1995 the trend was reversed. There was a higher concentration of sucrose in 1995. In general, Walla Walla onions showed a higher sugar: pyruvic acid ratio among different entries compared to short-day (Vidalia and Texas Grano 1015Y) onions.

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Robert P. Sabba and Bill B. Dean

Potato tubers (Solanum tuberosum) of genotypes that vary in resistance to dark pigment formation when damaged, characteristic of the physiological disorder blackspot, were assayed for free tyrosine. The tubers were also assayed for relative levels of chorismate mutase and proteinase activities, which can regulate free tyrosine levels. The susceptibility of potato tubers to blackspot was shown to be correlated to the amount of free tyrosine by third order regression (R = 0.88). Tyrosine was found to be a limiting factor in pigment development. Chorismate mutase activity (CMI and CMII) was not correlated to blackspot susceptibility of the genotypes studied. Proteinase activities of Atlantic, TXA 763-5, Ranger Russet, Russet Burbank, and Lemhi Russet tuber protein extracts measured with synthetic substrates correlated with blackspot susceptibility. This suggests that the high free tyrosine levels associated with blackspot susceptibility may be due to high levels of proteinase activity in the tuber, rather than tyrosine synthesis.