Tropical horticultural crops can be the spark that builds student interest in horticulture. They are a refreshing alternative to the temperate crops that most of our curricula are necessarily built around. Students who become familiar with production problems and opportunities between 30° north and south latitudes are better equipped to compete in the world economy. HORT 423 covers tropical ecology, soils, atmosphere, and many major crops. Beverage crops studied are cacao, coffee, and tea. Fruit and nut crops include bananas, mango, papaya, pineapple, dates, oil palm, coconut, macadamia, cashew, and Brazil nuts. Spices such as vanilla, black pepper, allspice, nutmeg, mace, cinnamon, cassia, and cloves are studied. Subsistence crops such as cassava, yam, taro, pigeon peas, chick peas, vegetable soy beans, and black beans round out an exciting semester that draws students. HORT 423 is a 3-hour-per-week lecture demonstration course supplemented with slides from the tropical countries. Many students simultaneously enroll in a 1-hour HORT 400 course that is taught during the 1-week spring break in a tropical country. Recent trips have been two each to Costa Rica and Guatemala. These study trips are gaining in popularity. For more information about HORT 423 consult the world wide web at http://http.tamu.edu:8000/~c963/a/h423main.html.
J. Benton Storey
J. Benton Storey
The Trans Texas Video Conference Network (TTVN) has been linked to all Texas A&M Univ. campuses and most of the Regional Research and Extension Centers. The College of Agriculture and Life Sciences has funded an aggressive project of establishing TTVN class rooms in many departments across the College Station campus, including The Horticultural Science Dept. in 1997. The first two Hort courses taught were HORT 422 Citrus and Subtropical Fruits in Fall 1996 and HORT 418 Nut Culture in Spring 1997. This extended the class room 400 miles south to Weslaco, 300 miles north to Texarkana and Dallas, and 700 miles west to El Paso. Students at each site had video and audio interaction with the professor and with each other. Advantages included the availability of college credit courses to areas where this subject matter did not previously exist, which helps fulfill the Land-grant University Mission. Quality was maintained through lecture and lab outlines on Aggie Horticulture, the department's Web home page, term papers written to ASHS serial publicationspecifications, and rigorous examinations monitored by site facilitators. Lecture presentations were presented via Power Point, which took about twice as long to prepare than traditional overhead transparencies. Administrative problems remain, but will be solved when the requested Distance Education Registration Category is initiated so that subvention credit can be shared. The lecture portion of the graduate course, HORT 601 Nutrition of Horticultural Plants, will be taught in the fall semester 1997 at eight sites throughout the state.
J. Benton Storey
Interactive television was successfully used in the fall semester, 1997, to teach a graduate course on nutrition of horticultural plants to resident students at TAMU—College Station and distance education students at TAMU—Commerce, TAMU—Texarkana, and Tarleton State Univ. These campuses are connected with fiber-optic telephone lines, which constitutes the Trans-Texas Video Conference Network. This medium was used by county extension agents, who are working toward graduate degrees, to progress toward graduation and a higher salary. The lab portion of the course was taught on the College Station campus, but distance sites received only the lecture portion with an option to come to College Station in the summer to take the lab as a separate 1-hour, week-long course.
S. Miyamoto and J. Benton Storey
Irrigated pecans in the southwestern United States have been planted in every soil imaginable, and tree performance has become highly soil-dependent. Desperate attempts to deal with this poor soil selection has led to advancements in soil management, consisting primarily of physical measures, such as chiseling and trenching. Chemical amendments appear to have played a secondary or supplemental role. Meanwhile, soil structural degradation, mainly compaction and aggregate destruction, began to cause poor water penetration, die-back of deep roots, and resultant loss of tree vigor. These problems have been dealt with primarily by chiseling. In the future, spiking and sodded-floor management are likely to become increasingly important. Scientific examination of soil management practices has lagged, but has provided some rationale and targets for soil management. H should play an increasingly important role in refining these measures and in establishing a comprehensive soil management program in which the soil is viewed as a plant growth medium and an integral component of cost-effective orchard management.
S. Miyamoto, J. Henggeler and J. Benton Storey
Irrigated production of pecans in the southwestern United States started with notoriously inefficient flood irrigation along river basins. Today, most surface-irrigated orchards are laser-leveled, and many orchards in upland areas are under sprinkler or drip irrigation. Technical and scientific knowledge for improving water management also has evolved from studying drought effects on tree performance to an improved understanding of water relations, salt effects, evapotranspiration processes, and the distribution of water and salts in irrigated fields. Yet, many growers still experience difficulties with water management and may benefit from maintaining the soil water suction above saturation but below 30 to 40 cb until shuck opening. The soil salinity should be kept below 2.5 dS·m−1, and irrigation water should be applied to essentially the entire root zone for optimum tree growth. Due to extreme soil variability existing in most irrigated fields of the southwestern region, these guidelines alone are not adequate. Soil profiles, root distributions, water quality, and irrigation methods may have to be examined to improve water management.
Charles J. Graham and J. Benton Storey
Pollarded `Wichita' pecan [Carya illinoensis (Wang) K. Koch] trees received 2 g uniconazol (UCZ) per tree using four application methods (trunk band, canopy soil injection, crown soil injection, and crown drench). All application methods increased trunk diameter but reduced shoot length, number of lateral shoots per terminal, nodes per terminal, internode length, and leaflets per compound leaf. Only the crown drench reduced leaf area. Area and dry weight per leaflet, and leaflet chlorophyll concentration were not affected by UCZ application. Effectiveness in growth reduction, as assessed by shoot elongation, was crown soil drench > crown soil injection > canopy soil injection > trunk band > control. All application methods increased viviparity. However, total yield per tree, nut size, and percentage of kernel were not affected. Chemical name used: (E)-1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazol).
Dan Chapman, Laurence Sistrunk and J. Benton Storey
In 1990, a randomized design was set up in a 33 year old orchard on Westwood silty clay loam with 4 main treatment factors: 1990 nut size, chiseling, aeration, and cultivar. Location for this experiment was the Adriance Orchard on the Texas A&M Plantation – Brazos River flood plain. Nut quality was determined by the % kernel and # nuts / kg. Yield was measured per tree and calculated for g/cm2 cross-sectional trunk area. The soil bulk density for each treatment was 1.53 g/cm3 and found to be statistically uniform at the start of the experiment. Results after one year showed that aeration increased the nut size and % kernel of `Mahan' but not of `Desirable' and `Stuart'. Chiseling increased the yield of `Stuart' and `Desirable' and nut size of all 3 cultivars but not % kernel. Aeration increased the % kernel from a mean 48.6% to 56.8% and nut size from 129 nuts/kg to 102 nuts/kg of the 1990 small-nut-size trees but did not significantly increase nut quality for the 1990 normal-nut-size trees.
Laurence Sistrunk, Dan Chapman and J. Benton Storey
The influence of temperatures during nut filling on nut size, kernel percentage, kernel color, percent oil, and fatty acid composition were evaluated over 3 years in `Cheyenne', `Mohawk', and `Pawnee' pecans [Carya illinoenensis (Wangenh.) C. Koch]. Nuts were harvested at shuck split at 14 sites located in Texas, Oklahoma, Kansas, Nebraska, Arizona, and California and Coahuila, Mexico. Weather data for 12 weeks before shuck split at each site were used to determine degree days by the formula: degree days = summation n(m–t) where n = number of days, m = (max + min temperature) ÷2, and t = 10°C. The degree days ranged from 996 to 1675. The oleic: linoleic ratios in all three cultivars were positively correlated with degree days in 2 of 3 years. `Mohawk' nut size was positively correlated with degree days all 3 years and `Cheyenne' and `Pawnee' were larger 2 of 3 years in the warmer climates. `Pawnee' kernel percentage and oil content was higher in the warmer climates. Warmer developmental temperatures had no influence on `Cheyenne' kernel color. `Mohawk' kernels were not affected 2 of 3 years, but `Pawnee' developed darker colors 2 of 3 years.
Dan Chapman, Laurence Sistrunk and J. Benton Storey
Objectives of this experiment were: 1) to determine what effect a soil spike aerator had on nut quality and yield, and 2) to determine whether soil compaction influenced nut quality and yield.3) to determine whether tree stress influenced nut quality or yield on pecan trees In 1990, a randomized design was set up in a 33 year old orchard on Westwood silty clay loam with 3 main treatment factors: 1990 nut size (measure of tree stress), aeration, and cultivar. Location for this experiment was the Adriance Orchard on the Texas A&M Plantation - Brazos River flood plain. Nut quality was determined by the % kernel and # nuts/kg. Yield was measured in kg per tree. Results after two years showed that aeration increased the nut size of stressed trees in 1991 and non-stressed trees in 1992 Yield was unaffected by aeration in both years but stressed trees produced lower yields in 1992. Aeration increased nut size, but not significantly from 119 nuts/kg to 111 nuts/kg in 1991. There was a significant increase with aeration in 1992 from 121 nuts/kg to 113 nuts/kg. Yield and % kernel were not significantly different for both years with aeration Stress did not increase % kernel in either 1991 or 1992 but nut size was larger on non-stressed trees for both years. Stressed trees produced fewer nuts per tree in 1992.