advice on data analysis, Linda Dodge for technical assistance, and Nurserymen's Exchange, Half Moon Bay, for kindly supplying the plants. The experiments were supported by a grant from the Danish Agricultural and Veterinary Research Council (grant no. 13
Margrethe Serek, Michael S. Reid and Edward C. Sisler
Margrethe Serek, Edward C. Sisler and Michael S. Reid
for advice on data analysis and Nurserymen's Exchange, Half Moon Bay, and Golden State, Watsonville, Calif., for kindly supplying the plants. The experiments were supported by a grant from the Danish Agricultural and Veterinary Research Council (grant
M. Elena Garcia*, Lorraine P. Berkett and Terry Bradshaw
A new biopesticide has been commercially available to apple growers since 2001 in the kaolin clay-based product. This material meets Federal standards for use in organic crop production as a potential replacement for some insecticides that manage key apple insect pests. Initial research indicated that kaolin might have non-target impacts such a reduction in canopy temperature. However, most of the research on non-target effects, such as impacts on fruit quality, has been conducted in warmer, semi-arid environments. These potential impacts may not be beneficial in cooler orchard environments. The objectives of this 3-year study are to determine potential non-target effects of Surround WP application in the relatively cool and moist climate of the Northeast on `McIntosh'/M.26 apple tree productivity, and fruit quality. In 2001, preliminary data were collected and are included in these results. Treatments include: (1) Surround beginning at green tip plus fungicides; (2) Surround beginning at green tip without fungicides; (3) Surround beginning at petal fall plus fungicides; (4) IPM; and (5) Nontreated control. In 2001, the control treatment received fungicides. For 2002 and beyond, the protocol was amended to remove fungicides treatments. Data analysis indicate significant differences in treatments for several of the variables measured (fruit weight, percent drop, yield efficiency, starch index, soluble solids, fruit packout, and insect and disease damage). However, some of these differences might be due to the high incidence of scab in the treatments that received no fungicides and not due to the effect of Surround. There were no significant differences in other variables measured such as thinning, fruit color, and spur diameter.
Steven E. Newman* and Robert O. Miller
Greenhouse and nursery managers rely on testing laboratories with the expectations of accuracy and consistency. The Greenhouse and Nursery Media Analysis Proficiency (GNMAP) Testing program was initiated to provide laboratories servicing greenhouses and nurseries with inter-laboratory quality control. The GNMAP program operational guidelines are based on those outlined under ISO 9000, ISO/IEC Guide 43 and Draft ISO/IEC Guide 24, which describe the requirements for proficiency testing. Nine laboratories enrolled in the program in 2003 and submitted results for root zone media and fertilizer solutions. Data analysis provided the minimum, maximum and median values; median absolute deviation (MAD); overall reproducibility (Rd); individual reported lab values; repeatability (Rp) of lab value (CV for the individual lab); and mean lab value reported. The Rd was calculated from the median of all lab Rp values and is a measure of intra-lab variance. A measure of inter-lab variance was determined by calculating the relative median deviations (RMD = MAD/Median × 100). For one of the media distributed, results for the saturated media extract included median pH values from 4.3 to 6.9 with MAD values averaging 0.1 across the three samples. The electrical conductivity (EC) median values ranged from 0.36 to 4.57 dS/m with RMD averaging 31% of the median. The main variability between laboratories for the majority of the macro cations was closely aligned with measured EC. Cations (K, CA and Mg) concentrations ranged from 17 to 502 mg/L with Ca typically in the greatest concentration. Cation inter-lab precision, based on the RMD ranged from 9-32% across the three substrate samples. The greatest RMD was 31.8% for Ca and 9.2% for K. The Rd values for the cations averaged 5%.
Jean-Jacques B. Dubois*, Frank A. Blazich and C. David Raper
Research by the authors has demonstrated the effect of day/night temperature difference (Tdiff) on plant growth is as substantive as the effect of daily average temperature (DAT). Dependence of plant primary productivity on temperature cannot be assessed with fewer than two data per 24 hours. Thus, the same experimental approach was applied to time to anthesis in Delphinium cultorum Voss `Magic Fountains' and Stokesia laevis L. `White Parasols', and to survival in D. cultorum. Two hundred and seventy seedlings of D. cultorum and 72 plantlets of S. laevis were grown for 56 days in growth chambers under eighteen 12 hour day/12 hour night combinations of six day and six night temperatures (10, 15, 20, 25, 30, or 35 °C). Ninety plants of D. cultorum were harvested after 13, 34, or 56 days, and 36 plants of S. laevis after 34 or 56 days. For each event of interest (anthesis or death), one datum per plant was recorded, consisting of time elapsed when either the event occurred, or the plant was harvested, whichever came first. Each datum was paired with an indicator of whether the plant was harvested prior to the event being observed. Data were analyzed using time—to—event data analysis procedures. Several parametric distributions fitted the data equally well, and both day and night temperature had strong effects on time to anthesis and survival time. However, in contrast with biomass production, DAT was quite sufficient to account for timing of these developmental events in relation to temperature. Addition of Tdiff contributed marginally to the fit to the data, but the magnitude of the effect was considerably smaller. Within the range of temperatures likely to be encountered in cultivation, the effect was negligible.
Kent D. Kobayashi
How do we enhance the learning experience of graduate students in scientific writing, an essential skill in their professional development? A graduate course TPSS 711 “Scientific Writing for Graduate Students” was developed to address this need. Its objectives were to help students write, analyze, and revise parts of a scientific paper; critically evaluate their own writing and the writings of others; and become familiar with types of publications. The diverse topics included purpose of scientific writing; organizing your writing; parts of a scientific paper; data analysis and growth analysis; writing the content of a poster or oral presentation; newspaper articles and popular works; extension publications; technical writing for the general public; thesis/dissertation writing; a journal editor's perspective; and reviewing a manuscript. TPSS 711 had an enrollment of 11 TPSS master's students. Students were in their second through fifth semesters of their graduate program. A student survey showed no student had submitted a manuscript to a peer-reviewed journal, had a peer-reviewed article published, or had a newspaper, trade magazine, or popular work published. Only 9% of the students had a paper published in a conference proceedings or presented a scientific paper outside Hawaii, with only 18% having presented a paper in Hawaii. Writing assignments, in-class activities, and evaluations of the writings of others helped students gain intensive hands-on experience in scientific writing. As a course requirement, students submitted an abstract and presented a paper at our college's annual scientific symposium. Course evaluations indicated this course was important and valuable in helping enhance the students' learning experience.
Clyde Wilson, Xuan Liu, Scott M. Lesch and Donald L. Suarez
Over the last several years, there has been increasing interest in amending the soil using cover crops, especially in desert agriculture. One cover crop of interest in the desert Coachella Valley of California is cowpea [Vigna unguiculata (L.) Walp.]. Cowpea is particularly useful in that as an excellent cover crop, fixing abundant amounts of nitrogen which can reduce fertilizer costs. However, soil salinity problems are of increasing concern in the Coachella Valley of California where the Colorado River water is a major source of irrigation water. Unfortunately, little information is available on the response of cowpea growth to salt stress. Thus, we investigated the growth response of 12 major cowpea cultivars (`CB5', `CB27', `CB46', `IT89KD-288', `IT93K-503-1', `Iron Clay', `Speckled Purple Hall', `UCR 134', `UCR 671', `UCR 730', `8517', and `7964') to increasing salinity levels. The experiment was set up as a standard Split Plot design. Seven salinity levels ranging from 2.6 to 20.1 dS·m–1 were constructed, based on Colorado River water salt composition, to have NaCl, CaCl2 and MgSO4 as the salinization salts. The osmotic potential ranged from –0.075 to –0.82 MPa. Salt stress began 7 days after planting by adding the salts into irrigating nutrient solution and ended after 5 consecutive days. The plants were harvested during flowering period for biomass measurement (53 days after planting). Data analysis using SAS analysis of variance indicated that the salinity in the range between 2.6 and 20.1 dS·m–1 significantly reduced leaf area, leaf dry weight, stem dry weight and root dry weight (P ≤ 0.05). We applied the data to a salt-tolerance model, log(Y) = a1 + a2X + a3X2, where Y represents biomass, a1, a2 and a3 are empirical constants, and X represents salinity, and found that the model accounted for 99%, 97%, 96%, 99%, and 96% of salt effect for cowpea shoot, leaf area, leaf dry weight, stem dry weight and root dry weight, respectively. We also found significant differences (P ≤ 0.05) of each biomass parameter among the 12 cultivars and obtained different sets of the empirical constants to quantitatively describe the response of each biomass parameter to salinity for individual cowpea cultivars. Since a significant salt × cultivar interaction effect (P ≤ 0.05) was found on leaf area and leaf dry weight, we concluded that salt tolerance differences exist among the tested cultivars.
Soon O. Park, Dermot P. Coyne, Geunhwa Jung, Paul W. Skroch, E. Arnaud-Santana, James R. Steadman, H.M. Ariyarathne and James Nienhuis
Our objective was to identify quantitative trait loci (QTL) for seed weight, length, and height segregating in a recombinant inbred line population derived from the common bean (Phaseolus vulgaris L.) cross `PC-50' × XAN-159. The parents and progeny were grown in two separate greenhouse experiments in Nebraska, and in field plots in the Dominican Republic and Wisconsin. Data analysis was done for individual environments separately and on the mean over all environments. A simple linear regression analysis of all data indicated that most QTL appeared to be detected in the mean environment. Based on these results, composite interval mapping (CIM) analysis was applied to the means over environments. For seed weight, strong evidence was indicated for five QTL on common bean linkage groups (LGs) 3, 4, 6, 7, and 8. Multiple regression analysis (MRA) indicated that these QTL explained 44% of the phenotypic variation for the trait. Weaker evidence was found for three additional candidate QTL on bean LGs 4, 5, and 8. All eight markers associated with these QTL were significant in a MRA where the full model explained 63% of the variation among seed weight means. For seed length, CIM results indicated strong evidence for three QTL on LG 8 and one on LG 2. Three additional putative QTL were detected on LGs 3, 4, and 11. The markers associated with the three seed length QTL on LG 8, and the QTL on LGs 2 and 11 were significant in a MRA with the full model explaining 48% of the variation among seed length means. For seed height, three QTL on LGs 4, 6, and 11 explained 36% of the phenotypic variation for trait means. Four of the seven QTL for seed length and two of three QTL for seed height also appeared to correspond to QTL for seed weight. Four QTL for common bacterial blight resistance [Xanthomonas campestris pv. phaseoli (Smith Dye)] and for smaller seed size were associated on LGs 6, 7, and 8. The implications of these findings for breeders is discussed.
P.P. Moore, T.M. Sjulin, B.H. Barritt and H.A. Daubeny
Extension Unit; R.A. Norton, Washington State Univ. Mt. Vernon Research and Extension Unit. The assistance of J.A. Robbina in coordinating the studies and data analysis is also gratefully acknowledged. The cost of publishing this paper was defrayed in part
Margrethe Serek, Rodney B. Jones and Michael S. Reid
Nishimoto, and the late F. Jackson Hills with data analysis, Linda Dodge and Mercedes Fernandez Sanchez for technical assistance, and Suyeyasu Wholesale Florists and Glad-Away Gardens for generous donations of gladiolus flowers. The cost of publishing this