Research in the Klamath Basin 2010 Annual Report
Grindelia- A drought-tolerant, new domestic source of industrial resins for the Klamath Basin: 2010 Results
Richard J. Roseberg and Rachel A. Bentley1
Introduction
Background
Resinous compounds known as ‘Naval Stores’ were once used to caulk wooden ships, but now these compounds (including turpentine, fatty acids, rosins, and their derivatives) are used in large quantities by the papermaking industry(Thompson 1990; Hoffmann and McLaughlin 1986). These resins are incorporated into the liquid pulp or as a coating on the finished paper to improve color brilliance and ink permanence, while eliminating ink ‘bleeding’. These compounds are also used in smaller amounts for producing rubber, chemicals, ester gums, and resins for many other specialty applications (i.e. rosin used on baseball bats and violin bows). The primary current source for these resinous compounds is tapping old-growth pine trees, or by grinding up their stumps after logging. The complex chemical structure of these resins cannot be synthesized from petroleum or other simple oils. US
1 Associate Professor and Faculty Research Assistant, respectively, Klamath Basin Research and Extension Center, Klamath Falls, OR.
Reference to a product or company is for specific information only and does not endorse or recommend that product or company to the exclusion of others that may be suitable. ______Klamath Basin Research and Extension Center Grindelia- a Drought-Tolerant, New Domestic Source of Industrial Resins for the Klamath Basin, 2010.
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consumption of these resins was fairly static from the 1960s until the 1990s at about 550,000 ton/yr, but in recent years the increased demand for fine paper for ink-jet, laser- jet, and copier applications as well as increased use of recycled paper have increased demand for paper sizing chemicals, including resins. US production (which once met the demand) has nearly disappeared. In recent years, this need has been met by increased imports of resin primarily from China (60% of world production), Brazil (20%) and nearby countries. These supplies are potentially unreliable and expensive. About 60% of the world resin comes from tapping live trees (with the remainder from grinding up tree stumps after logging), and 70% of the live tree market is controlled by China. Since 1990, the price of gum resin has ranged between $0.20 and $1.13/lb, with a general upward trend. Price spikes have been more common in recent years. Except for these periodic price spikes, prices since 2000 have often been in the range of $0.36 to $0.54/lb. In the early 1980s, it was discovered that Grindelia camporum and related species produce large quantities of a valuable diterpene resin (grindelic acid) that is nearly identical to the high quality resins from pine trees (Guerreiro et al. 1981; Bohlmann et al. 1982; McLaughlin and Hoffmann 1982; Timmermann et al. 1983). G. camporum is a perennial shrub, native of the western US, especially the central valley of California, and seems to grow well under non-irrigated conditions (Bailey 1976; Hoffmann et al. 1984; Hoffmann and McLaughlin 1986). In natural stands, grindelia seems to prefer soils higher in clay content, but this may be due to the greater water holding capacity of the soil in xeric climates rather than a preference for the drainage or texture of a clay soil per se. Diterpene resin acids constituted between 65 and 75% of the total crude resin in the plant (Hoffmann and McLaughlin 1986; McLaughlin 1986a, b). Studies on the heritability of resin production indicate that genetic improvement is feasible (Dunford 1964; McLaughlin 1986a, b; McLaughlin and Linker 1987). In small, early tests in Arizona, experimental tetraploid lines of G. camporum yielded up to 5.6 ton/ac biomass per year, with a crude resin content of up to 11%, resulting in annual crude resin yields of up to 1,200 lb/ac, using between 22 and 30 inches of irrigation water (Hoffmann and McLaughlin 1986; McLaughlin and Linker 1987). Although G. camporum received more initial interest than other species due to its greater size, later studies identified a South American native, Grindelia chiloensis, as also having commercial potential (Timmermann and Ravetta, 1990). For G. camporum, glands on the surface of flowers are responsible for most of the resin production, with less resin produced on the leaves, and almost none on the stems (Hoffmann et al. 1984; Roseberg, 1996a). In contrast, G. chiloensis plants are typically smaller, but they have a large number of resin glands on all above-ground plant surfaces (flowers, leaves, and stems) and thus may also have potentially large resin production on a per acre basis. (Ravetta et al., 1996a and 1996b).
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Future Prospects- Likely Production Areas
Due to reasons of weather and labor markets, China is unlikely to be able to rapidly increase their resin output if global markets expand, pointing towards likely upward resin price pressure in the future. Looking to the future, chemical companies have shown an increased interest in developing a stable, domestic source of these resins. Grindelia (the generic term for both species) is likely suited to areas that are dry and warm. Deep soils would decrease the need for irrigation, as would presence of some clay. It is somewhat frost tolerant and a perennial, making it useful in temperate climates. Likely areas would include western US, western Australia, northern Africa, southern Europe, central China, and southern areas in South America. However, there may be differences in local adaptation that could favor production of either G. camporum or G. chiloensis, depending on the particular situation. A brief economic analysis of grindelia’s potential follows: If grindelia resin were conservatively valued at $0.40/lb, a biomass yield of 12 ton/ac with a crude resin yield of 1.2 ton/ac would be worth $960/ac after extraction. Due to resin extraction and processing costs, farm gate values for raw material could be estimated at 50%, or $480/ac. The likely reduced input costs would contribute to a farmer's net return from a grindelia crop (mainly due to presumed reduced irrigation and fertilizer requirement) compared to other crops. Because grindelia is a perennial, establishment costs would be reduced, further adding to a farmer's net return (assuming good winter survival and annual stand regrowth). Thus, the return could prove attractive in areas where the expense or lack of irrigation water limits other crops.
Recent Research
Grindelia camporum near Medford Oregon, 1995
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After the initial studies in the early to mid-1980s confirming grindelia’s unusual ability to produce these resins, virtually no crop research was done until the mid-1990s when several small agronomic studies on G. camporum were begun by Dr. Roseberg at the Oregon State University Southern Oregon Research & Extension Center (SOREC) (Roseberg, 1996a). These studies, conducted in both sandy loam and clay soil types, showed grindelia could grow well and persist over multiple years in that climate. Overall, biomass yields ranged from 3.0 to 15.7 ton/ac, resulting in resin yields ranging from 750 to 3,940 lb/ac (Roseberg, 1996b). In the mid-1990s studies were also begun on G. chiloensis in Argentina by Dr. Damian Ravetta of the Universidad de Buenos Aires, focusing on wild plant collection, selection, plant physiology, and agronomic work (Ravetta et al., 1996b). In the late 1990s we also cooperated with Dr. Ravetta, comparing performance of the same G. chiloensis cultivars in Argentina and Oregon (Roseberg and Ravetta, 2003). Since then, Dr. Ravetta has continued with cultivar selection and improvement in Argentina, and now has several lines that appear more promising than those available in the late 1990s. He has also continued work on crop management aspects, such as N fertilization, air temperature, water use, response to light intensities, and related factors (Zavala and Ravetta, 2001; Wassner and Ravetta, 2005 and 2007). No further research occurred in the US until 2010, when we received another small grant to resume studies through 2011 under the very different climate conditions found at KBREC. The South-Central Oregon region may be well suited to grindelia because it is sunnier, yet cooler than the Rogue Valley or California’s central valley. Previous results in Oregon suggested the possibility of achieving high biomass production without dramatically decreasing resin content. Despite grindelia’s potential, many agronomic requirements of grindelia and their effects on yield and resin production are still unknown. The plant's resinous nature could make harvest with standard cutting equipment difficult. Commercial processing procedures need to be developed, and product development using grindelia biomass as a raw material is necessary also. Winter survival of both G. camporum and G. chiloensis may be more of an issue in the Klamath Basin, and both management and abiotic factors affecting survival of the various cultivars of both species are not well understood. Other crop management practices such as plant density, irrigation, etc. still need to be worked out for both G. chiloensis and G. camporum. We did some preliminary tests on seed germination requirements in the 1990s, as others also did earlier on (McLaughlin and Linker, 1987; Zafar et al., 1994), but have not yet developed dependable procedures for direct seeding in the field, as essentially all field research to date has been done with transplants.
Objectives
Given the many unknowns involved with domesticating grindelia into a viable commercial crop, based on limited funding resources we focused on the following objectives for 2010 and 2011 research trials at KBREC.
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1. Evaluate growth, biomass yield, resin yield, and over-wintering persistence of several accessions of G. chiloensis and G. camporum in the Klamath Basin.
2. Evaluate response of G. chiloensis and G. camporum to variations in plant density, irrigation rate, and nitrogen fertilization.
Summary of Procedures
For these trials, seed of five accessions of G. chiloensis was provided by Dr. Damian Ravetta from his germplasm collection at the University of Buenos Aires. In this report, these are designated as “ChXXX” indicating “Chiloensis” followed by the three digit accession number as denoted by Dr. Ravetta. Seed of eight accessions of G. camporum was provided by Dr. Leslie Gunatilaka at the University of Arizona, Southwest Center for Natural Products, from the stored collection of retired University of Arizona scientist Steve McLaughlin. In this report, these are designated as “AXXX” indicating they were originally collected in Arizona, followed by the three digit accession number as denoted by Dr. McLaughlin. For simplicity, all these accessions will be referred to as “cultivars” of the two species throughout this report.
During the late winter of 2010, seed for all trials was started in flats in the greenhouse, and seedlings were transplanted to the field in spring 2010 as described below for the various trials. All trials were conducted at KBREC (Poe fine sandy loam). For each trial, weeds were controlled by mechanical and manual cultivation only. After initial irrigation of all plots to encourage uniform recovery from transplantation, irrigation rates were decided based on the Kimberly-Penman evapotranspiration (Et) calculated by the US Bureau of Reclamation Agricultural Meteorological (AgriMet) automated weather station located at KBREC (US Bureau of Reclamation, 2010). In the irrigation response trial, irrigation was applied at rates and times sufficient to keep ______Klamath Basin Research and Extension Center Grindelia- a Drought-Tolerant, New Domestic Source of Industrial Resins for the Klamath Basin, 2010.
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cumulative irrigation plus precipitation at or just above 60% of calculated Et in the ‘high’ irrigation treatment, 40% of Et in the ‘medium’ irrigation treatment, and 20% of Et in the ‘low’ irrigation treatment. In the fall, above- ground biomass was cut by hand, air-dried and then oven-dried for a week at 30oC - 50oC, and weighed. Sub samples were separated into the flower, stem, and leaf plant parts. All samples were shipped to Dr. Ravetta’s lab in Argentina for resin analysis in early 2011. In past studies at SOREC and in Argentina, we have observed improved winter survival if plants were cut approximately 8 inches above ground surface at harvest instead of cutting just above ground level. Leaving a short section of stem in this way seemed to improve winter survival for G. chiloensis more than for G. camporum. To measure whether this effect would also occur in the colder winters at KBREC, certain plants within each plot were cut off at either 8 inch height or at ground level and their survival and performances were tracked separately in 2011. For each experiment and treatment, over-wintering survival rate was measured on May 27, 2011. In addition to the trials described below, the trial designed to measure grindelia’s response to nitrogen fertilizer was also set up and transplanted in spring, 2010. This trial included one G. camporum and two G. chiloensis cultivars, all grown in the ‘medium’ irrigation treatment. The N fertilizer treatments were not applied to this trial in 2010 due to the overall small plant size for both species by mid-summer. It was decided to postpone these treatments until the 2011 growing season to measure the impact of N on larger (higher yielding) plants which we expected to observe in the second year (2011), and thus results from the nitrogen response trial will not be discussed further here, but will be discussed in the 2011 report. All measured parameters were analyzed statistically using SAS® for Windows, Release 9.1 (SAS Institute, Inc.) software. As appropriate, analysis of variance was calculated according to the individual experiment’s design. Treatment significance was based on the F test at the P=0.05 level. If this analysis indicated significant treatment effects, least significant difference (LSD) values were calculated based on the student’s t test at the 5% level.
I. Plant Density x Cultivar Trials
Materials and Methods
Because G. camporum is typically a much larger plant than G. chiloensis, the range of likely plant densities would not be equal in most cases. Because the two species’ plant spacing treatments were usually not equivalent (and thus not directly comparable), statistics for the two species were analyzed separately. One G. camporum (A173) and two G. chiloensis cultivars (Ch743 and Ch775) were transplanted in rows to create four densities. The two G. chiloensis cultivars reportedly have similar plant architecture but different resin contents, which would allow us to evaluate how growth and resin yield may vary for high and low resin plants and plant parts as a function of plant density (Damian Ravetta, pers. comm., 2010). For G. chiloensis, the four between-row and within-row plant spacings were 12 x 30 inch; 12 x ______Klamath Basin Research and Extension Center Grindelia- a Drought-Tolerant, New Domestic Source of Industrial Resins for the Klamath Basin, 2010.
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20 inch; 12 x 12 inch; and 12 x 8 inch. The four between-row and within-row plant spacings for G. camporum were 30 x 60 inch, 30 x 30 inch, 12 x 30 inch, and 12 x 12 inch. For both species, each density treatment was replicated four times. Whenever possible, plants harvested for resin analysis or biomass were taken from the interior of a given plot to minimize edge effects. Thus, G. camporum data was analyzed as a randomized complete block design, and G. chiloensis data was analyzed as a complete factorial design, with cultivar and density as the two factors. G. camporum was transplanted to the field on June 23 when most plants were about 3-4 inches tall with 4-6 leaves. G. chiloensis was transplanted to the field on July 6 when most plants were about 2-3 inches tall with 3-5 leaves. The entire trial was grown in the ‘medium’ irrigation treatment, which received a total of 1.40 inches of rainfall plus 20.42 inches of irrigation from June 1 through October 31 (Table 1). Most of the irrigation was applied in June and July to ease transplant shock in the warm summer weather until plants were established. On November 7, individual leaves were collected from representative plants within each plot to allow calculation of mean surface area per leaf. On November 16, a single ‘typical plant from the interior of each G. camporum plot, and two typical plants from the interior of each G. chiloensis plot was harvested, dried, and separated into plant parts (flower, leaf, and stem) as described above, and later shipped to Argentina for resin analysis. Equipment problems, personnel issues, and international payment restrictions have delayed resin analysis, so resin data is not reported here. That data will be added to the report as soon as it is available and analyzed.
Results and Discussion
Grindelia camporum
Grindelia camporum near Klamath Falls, OR, 2010
Plant spacing did not have a significant effect on biomass yield per plant, but there was a significant difference due to plant spacing for biomass per acre as well as stem and leaf percent of biomass (Table 2). Thus the biomass yield was primarily controlled by number of plants per acre rather than size of individual plants, suggesting ______Klamath Basin Research and Extension Center Grindelia- a Drought-Tolerant, New Domestic Source of Industrial Resins for the Klamath Basin, 2010.
Research in the Klamath Basin 2010 Annual Report that maximum plant density was not achieved in this first year. The maximum mean treatment yield of just over 5 ton/ac (for the12 x 12 inch spacing) is lower than measured in mature grindelia stands in previous trials at SOREC, suggesting that larger yields may occur in the second year if winter survival is satisfactory. The small number of flowers also suggests plants did not have time to reach full size in the short period of active growth in the field in 2010. Plant spacing did not have a significant effect on flower percent biomass, but the differences for stem and leaf percent biomass were both significant. For some reason, G. camporum plants in the 30 x 30 inch spacing treatment grew taller (data not shown) with relatively more stem and less leaf biomass than in the other spacing treatments.
Grindelia chiloensis
Grindelia chiloensis near Klamath Falls, OR, 2010
Plant spacing did not have a significant effect on biomass yield per plant, but there was a significant difference in biomass yield per acre due to plant spacing (Table 2). G. chiloensis followed a pattern of biomass yield similar to G. camporum: higher density (closer spacing) resulted in higher biomass yield, suggesting that maximum plant density was not achieved in this first year. Plant spacing did not have a significant effect on partitioning of plant parts, although differences in percent stems was almost significant (P=0.066). There was a significant cultivar effect on biomass yield, flower percent, and leaf percent. For biomass yield, there was also a significant interaction between cultivar and spacing, so that the main significant cultivar yield effect was the higher biomass yield for Ch743 at the closest plant spacing only. Ch743 seemed to mature sooner, resulting in proportionally more flowers than for Ch775. In contrast, Ch775 tended to have proportionally more leaves at most row spacings.
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II. Irrigation Rate x Cultivar Trials
Materials and Methods
As in the plant density x cultivar trial described above, the two species were not inter-randomized and their statistics were analyzed separately. Eight G. camporum (A086, A121, A153, A165, A170, A171, A173 and A175) and five G. chiloensis cultivars (Ch743, Ch775, Ch750, Ch766, and Ch734) were transplanted within the three irrigation treatments described above. In some cases the number of plants per plot had to be adjusted due to limited number of plants for some cultivars. Among the G. camporum cultivars, only A173 had enough plants to allow plot replication (4 reps), but the G. chiloensis cultivars each were replicated from 2 to 4 times. Irrigation was applied uniformly through July to decrease transplant shock since transplantation occurred during warm mid-summer conditions (June 23 for G. camporum and July 6 for G. chiloensis), the same as the plant density x cultivar trial above (Table 1). After July, the irrigation treatments were imposed. Plant spacing was 30 x 30 inch for G. camporum and 12 x 20 inch for G. chiloensis in all cases (equal to the second widest spacing in the density x cultivar trial above). Data for both species was analyzed as a split plot design, with irrigation rate as the main plot and cultivar as the sub-plot. For G. camporum, the lack of plot replication for all cultivars but A173 prevented statistical comparison between cultivars, but observations of multiple plants of the other seven cultivars were possible.
As in the density x cultivar trial described above, individual leaves were collected from representative plants within each plot on November 7 to allow calculation of mean surface are per leaf. On November 16, a single ‘typical’ plant from the interior of each G. camporum plot, and two typical plants from the interior of each G. chiloensis plot was ______Klamath Basin Research and Extension Center Grindelia- a Drought-Tolerant, New Domestic Source of Industrial Resins for the Klamath Basin, 2010.
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harvested, dried, and separated into plant parts (flower, leaf, and stem) as described above, and later shipped to Argentina for resin analysis. Equipment problems, personnel issues, and international payment restrictions have delayed resin analysis, so resin data is not reported here. That data will be added to the report as soon as it is available and analyzed.
Results and Discussion
Grindelia camporum
Irrigation rate had a significant effect on biomass yield per plant, as well as biomass yield per acre (Table 3). In general, plants grew well even in the ‘low’ irrigation treatment, although increasing irrigation did seem to increase yield somewhat. As in the plant density trial, biomass yields were low compared to previous trials at SOREC. There was also a significant difference in percent flowers in the biomass. Increasing irrigation seemed to delay maturity (reduced proportion of flowers) but this was not true for all cultivars. Differences in percent stems and leaves due to irrigation rate were not significant. Without replication we cannot make firm conclusions about cultivar differences. However, it appears that in these observational plots, cultivars A153 and A175 were not as vigorous as the others, and that A170 did not grow well unless it received ‘medium’ or more irrigation. The most commonly tested cultivar (A173) performed well in this group, but others such as A086, A165 and A171 deserve further evaluation.
Grindelia chiloensis
Irrigation rate did not have a significant effect on biomass yield, flower percent, or stem percent (Table 3). Effect of irrigation was significant for leaf percent, with the highest leaf percent occurring in the ‘low’ irrigation treatment. Yield differences between cultivars were significant. Ch743 had consistently good yield under all irrigation regimes. Other cultivars had variable performance. For example, Ch734 had the lowest yield under ‘high’ and ‘low’ irrigation, but had the highest yield under ‘medium’ irrigation. Biomass yields in general were low compared to previous studies at SOREC, likely due to the short 2010 growing season. This was demonstrated by the significant difference in flowering percent between cultivars. Some cultivars did not reach flowering stage at all, and flowering percent was low across the board, indicating that G. chiloensis, like G. camporum, did not reach maturity by the fall harvest in 2010.
Summary
The short growing season after transplanting in 2010 resulted in insufficient time for both G. camporum and G. chiloensis to grow fully and reach maturity, resulting in
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low per-plant biomass and few flowers. Thus, biomass yield per acre was primarily controlled by plant spacing. Grindelia grew well even under the ‘low’ irrigation treatment, although some additional irrigation seemed to improve G. camporum’s growth somewhat. Some less-studied G. camporum cultivars deserve further investigation. Once the resin data are available, more definitive recommendations as to favored plant spacing, irrigation, and cultivar should be possible for both G. camporum and G. chiloensis. Overwintering survival and yield data to be collected in 2011 should also further elucidate the optimum management practices for this potential crop. Based on this preliminary data it appears the grindelia may have a place in the Klamath Basin under conditions of limited irrigation, but further investigation is necessary to either validate or disprove this tentative conclusion.
Acknowledgements
Special thanks to the following for their assistance with this research:
Damian Ravetta, Universidad de Buenos Aires, Argentina for providing the G. chiloensis seed and for performing resin analysis on harvested plant samples.
Dr. Leslie Gunatilaka (University of Arizona, Southwest Center for Natural Products), and Dr. Steve McLaughlin (University of Arizona, retired) for providing the G. camporum seed.
Partial funding for this research was provided by Agricultural Research Foundation Grant #ARF 7314.
References
Bailey, L.H. 1976. Hortus. (3rd ed.). Macmillan, New York.
Bohlmann, F., M. Ahmed, N. Borthakur, M. Wallmeyer, J. Jakupovic, R.M. King, and H. Robinson. 1982. Diterpenes related to grindelic acid and further constituents from Grindelia species. Phytochemistry 21:167-172.
Dunford, M.P. 1964. A cytogenic analysis of certain polyploids in Grindelia (Compositae). Am. J. Bot. 51:41-61.
Guerreiro, E., J. Kavka, J.R. Saad, M.A. Oriental, and O.S. Giordano. 1981. Acidos diterpenicos en Grindelia pulchella y G. chiloensis Cabr. Rev. Latinoam. Quim. 12:77- 81.
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Hoffmann, J.J., B.E. Kingsolver, S.P. McLaughlin, and B.N. Timmermann. 1984. Production of resins by arid-adapted astereae, p. 251-271. In: B.N. Timmermann, C. Stellink, and F.A. Loewus (eds.), Phytochemical adaptations to stress. Plenum, New York.
Hoffmann, J.J. and S.P. McLaughlin. 1986. Grindelia camporum: Potential cash crop for the arid southwest. Econ. Bot. 40:162-169.
McLaughlin, S.A. and J.J. Hoffmann. 1982. Survey of biocrude-producing plants from the Southwest. Econ. Bot. 36:323-339.
McLaughlin, S.P. 1986a. Heritabilities of traits determining resin yield in gumweed. J. Hered. 77:368-370.
McLaughlin, S.P. 1986b. Mass selection for increased resin yield in Grindelia camporum (Compositae). Econ. Bot. 40:155-161.
McLaughlin, S.P. and J.D. Linker. 1987. Agronomic studies on gumweed: Seed germination, planting density, planting dates, and biomass and resin production. Field Crops Res. 15:357-367.
Ravetta, D.A., A. Anouti, and S.P. McLaughlin. 1996a. Resin production of Grindelia accessions under cultivation. Industrial Crops and Products 5(3): 197-201.
Ravetta, D.A., F. Goffman, E. Pagano, and S.P. McLaughlin. 1996b. Grindelia chiloensis resin and biomass production in its native environment. Industrial Crops and Products 5(3): 235-238.
Roseberg, R.J. 1996a. Grindelia yield and resin production in Oregon. Abstr. p. 31. Association for the Advancement of Industrial Crops Annual Meeting.
Roseberg, R.J. 1996b. Underexploited temperate industrial and fiber crops. p. 60-84. In J. Janick, ed. Progress in New Crops. ASHS Press, Alexandria, VA.
Roseberg, R.J. and D.A. Ravetta. 2003. Yield and resin production of Grindelia camporum and G. chiloensis accessions grown in Patagonia, Argentina, and Oregon, USA. Abstr. p. 31, Association for the Advancement of Industrial Crops annual meeting.
Thompson, A.E. 1990. Arid-land industrial crops. p. 232-241. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.
Timmermann, B.N., D.J.Luzbetak, J.J. Hoffmann, S.D. Jolad, K.H. Schram, R.B. Bates, and R.E. Klenck. 1983. Grindelane diterpenoids from Grindelia camporum and Chrysothamnus paniculatus. Phytochemistry 22:523-525.
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Timmermann, B.N. and D.A. Ravetta. 1990. In search of a resin crop for arid lands in South America. Proc. First International Conference on Promising Crops for Arid and Semi-Arid Lands. Asuncion, June 17-22, 1990.
US Bureau of Reclamation, 2010. Agrimet: The Pacific Northwest cooperative agricultural weather network. http://www.usbr.gov/pn/agrimet/
Wassner, D.F and D.A. Ravetta. 2007. Nitrogen availability, growth, carbon partition, and resin content in Grindelia chiloensis. Industrial Crops & Products 25:218-230.
Wassner, D.F and D.A. Ravetta. 2005. Temperature effects on leaf properties, resin content, and composition in Grindelia chiloensis (Asteraceae). Industrial Crops & Products 21:155-163.
Zafar, S.I., W.H. Shah, and Z.U. Rehman. 1994. Studies on achene germination, transplantability, salinity tolerance, and cultivation of gumweed (Grindelia camporum) in hot and semi-arid conditions. Field Crops Research 37: 77-84.
Zavala, J.A. and D.A Ravetta. 2001. The effect of irrigation regime on biomass and resin production in Grindelia chiloensis. Field Crops Research 69: 227-236.
Table 1. 2010 Precipitation & irrigation for the grindelia irrigation rate x cultivar trial. Klamath Basin Research & Extension Center, Klamath Falls, OR.
"Wet" Block "Medium" Block "Dry" Block Precipitation Irrigation Irrigation Irrigation Irrigation Irrigation Irrigation Month (inch) (inch) Applications (inch) Applications (inch) Applications
June 0.52 3.91 3 3.91 3 3.91 3 July 0.15 11.17 12 11.17 12 11.17 12 August 0.23 4.72 5 3.36 5 1.32 2 September 0.05 2.64 3 1.98 2 0.99 1 October 0.45 0.99 1 0.00 0 0.00 0
Total 1.40 23.43 24 20.42 22 17.39 18 Total After Irrig. Treatments Began 0.73 8.35 9 5.34 7 2.31 3
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Table 2. 2010 Grindelia response to planting density, species, and cultivar under medium irrigation rate. Klamath Basin Research & Extension Center, Klamath Falls, OR.
Grindelia camporum, cultivar A173 Dry Wt Biomass Yield Yield (%) Plant Spacing (g/plant) (lb/ac) (ton/ac) Flower Leaf Stem
12x12 106 10182 5.09 5.3 89.5 5.3 12x30 114 4385 2.19 4.5 90.9 4.5 30x30 154 2363 1.18 3.3 53.8 42.8 30x60 92 710 0.36 5.5 88.9 5.5
Mean 117 4410 2.20 4.7 80.8 14.5 P Value 0.089 <0.001 <0.001 0.137 <0.001 <0.001 LSD (0.05) NSD 3368 1.68 NSD 5.2 3.8 CV (%) 26.1 47.7 47.7 27.2 4.0 16.2
Grindelia chiloensis, cultivars Ch743 & Ch775 Plant Dry Wt Biomass Yield Yield (%) Cultivar Spacing (g/plant) (lb/ac) (ton/ac) Flower Leaf Stem
Ch743 12x8 19.4 2789 1.39 9.4 77.6 13.0 12x12 17.2 1648 0.82 7.8 77.4 14.8 12x20 19.7 1133 0.57 6.7 72.3 21.0 12x30 19.1 734 0.37 6.1 80.6 13.3 Ch775 12x8 11.4 1639 0.82 0.0 77.8 22.2 12x12 19.1 1838 0.92 0.0 90.5 9.5 12x20 19.5 1126 0.56 6.8 79.6 13.6 12x30 18.3 701 0.35 2.7 83.3 14.0
Mean 18.0 1451 0.73 4.9 79.9 15.2 P (Cultivar) 0.196 0.019 0.019 0.034 0.037 0.677 LSD (0.05)‐ Cultivar NSD 205 0.10 4.7 5.4 NSD P (Spacing) 0.152 <0.001 <0.001 0.819 0.145 0.066 LSD (0.05)‐ Spacing NSD 290 0.14 NSD NSD NSD P (Cultivar X Spacing Interaction) 0.066 <0.001 <0.001 0.466 0.351 0.006 CV (%) 20.6 19.4 19.4 130.8 9.3 30.4
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Research in the Klamath Basin 2010 Annual Report
Table 3. 2010 Grindelia response to irrigation rate, species, & cultivar. Klamath Basin Research & Extension Center, Klamath Falls, OR.
Grindelia camporum Dry Wt Biomass Yield Yield (%) Irrigation Cultivar (g/plant) (lb/ac) (ton/ac) Flower Leaf Stem
High A086 287 4417 2.21 1.7 49.9 48.3 A121 288 4433 2.22 0.0 58.0 42.0 A153 32 487 0.24 0.0 100.0 0.0 A165 364 5586 2.79 1.4 51.2 47.5 A170 244 3746 1.87 0.0 59.7 40.3 A171 326 5004 2.50 1.5 48.8 49.6 A173 264 4065 2.03 2.0 49.6 48.4 A175 180 2768 1.38 0.0 65.8 34.2 Medium A086 349 5356 2.68 1.4 51.0 47.5 A121 110 1690 0.85 0.0 56.0 44.0 A153 32 488 0.24 0.0 100.0 0.0 A165 167 2568 1.28 3.0 59.9 37.1 A170 166 2544 1.27 0.0 66.1 33.9 A171 178 2738 1.37 2.8 57.4 39.9 A173 154 2362 1.18 3.3 53.8 42.8 A175 79 1213 0.61 0.0 68.4 31.6 Low A086 110 1686 0.84 4.6 60.9 34.6 A121 109 1674 0.84 4.6 59.8 35.7 A153 61 933 0.47 0.0 91.8 8.2 A165 216 3317 1.66 2.3 58.1 39.6 A170 52 807 0.40 0.0 80.6 19.4 A171 257 3950 1.98 2.0 61.1 36.9 A173 215 3308 1.65 2.5 49.4 48.1 A175 81 1242 0.62 0.0 65.8 34.2
Mean 189 2897 1.45 1.7 60.1 38.2 P (Irrigation) 0.011 0.011 0.011 0.021 0.555 0.352 LSD (0.05)‐ Irrigation 59 908 0.45 0.6 NSD NSD CV Irrigation (%) 30.0 30.0 30.0 36.4 8.6 13.7 P (Cultivar) nm* nm* nm* nm* nm* nm* LSD (0.05)‐ Cultivar nm* nm* nm* nm* nm* nm* CV Cultivar (%) nm* nm* nm* nm* nm* nm* P (Irrigation X Cultivar Interaction) nm* nm* nm* nm* nm* nm*
* nm = Not measured due to non‐replication of most varieties.
Grindelia chiloensis Dry Wt Biomass Yield Yield (%) Irrigation Cultivar (g/plant) (lb/ac) (ton/ac) Flower Leaf Stem
High Ch743 24.7 1421 0.71 4.7 78.2 17.1 Ch775 14.0 807 0.40 0.0 82.2 17.8 Ch750 13.9 802 0.40 0.0 80.2 19.8 Ch766 20.3 1172 0.59 5.6 75.8 18.6 Ch734 10.3 591 0.30 0.0 75.6 24.4 Medium Ch743 19.7 1132 0.57 6.7 72.2 21.0 Ch775 19.5 1126 0.56 6.8 79.6 13.6 Ch750 18.3 1052 0.53 0.0 79.2 20.8 Ch766 12.9 744 0.37 19.4 61.3 19.4 Ch734 21.6 1244 0.62 11.6 76.1 12.3 Low Ch743 21.0 1211 0.61 4.0 84.7 11.3 Ch775 18.3 1052 0.53 0.0 86.3 13.7 Ch750 14.0 806 0.40 0.0 92.1 7.9 Ch766 15.0 864 0.43 0.0 81.0 19.0 Ch734 13.1 756 0.38 0.0 89.5 10.5
Mean 17.7 1019 0.51 3.5 80.4 16.1 P (Irrigation) 0.559 0.559 0.559 0.600 0.014 0.120 LSD (0.05)‐ Irrigation NSD NSD NSD NSD 6.0 NSD CV Irrigation (%) 29.8 29.8 29.8 237.1 8.2 56.6 P (Cultivar) 0.042 0.042 0.042 0.005 0.276 0.549 LSD (0.05)‐ Cultivar 6.0 347 0.17 4.2 NSD NSD CV Cultivar (%) 27.9 27.9 27.9 108.0 11.1 52.2 P (Irrigation X Cultivar Interaction) 0.373 0.372 0.372 0.215 0.947 0.942 ______Klamath Basin Research and Extension Center Grindelia- a Drought-Tolerant, New Domestic Source of Industrial Resins for the Klamath Basin, 2010.