Vernonia oilseed production in the mid-Atlantic region of the United States

Industrial Crops and Products 12 (2000) 119 – 124 www.elsevier.com/locate/indcrop

Vernonia oilseed production in the mid-Atlantic region of the United States H.L. Bhardwaj a,*, A.A. Hamama a, M. Rangappa a, D.A. Dierig b a

Agricultural Research Station, Virginia State Uni6ersity, PO Box 9061, Petersburg, VA 23806, USA b USDA-ARS, US Water Conser6ation Laboratory, Phoenix, AZ 85040, USA Received 1 November 1999; accepted 19 March 2000

Abstract Epoxidized oils, manufactured by chemical epoxidation of fats and vegetable oils such as soybean [Glycine max (L.) Merr.], are useful in reformulation of oil based (alkyd-resin) paints to reduce emissions of volatile organic compounds that contribute to production of smog. Other potential markets for epoxy fatty acids include plasticizers, additives to polyvinyl chloride, polymer blends and coatings, cosmetic, and pharmaceutical applications. Currently, no oilseed crop has been commercialized as a source of natural epoxidized oils. However, Vernonia galamensis (Cass.) Less. has been identified to have potential for domestication as a new industrial oilseed source of natural epoxy fatty acids. The main objective of this research was to evaluate feasibility of vernonia production in mid-Atlantic region of the United States. Specifically, we wanted to evaluate available vernonia germplasm for seed yield, oil content, and oil quality, and to determine suitable production practices. The seed yield (kg/ha) in field experiments conducted from 1994, 1995, and 1996 at Randolph Farm of Virginia State University (37°15%N and 77°30.8%W), with a selected group of vernonia lines, ranged from 490 to 1288, 494 to 1394, and 1070 to 1934, respectively. Oil content ranged from 30.2 to 36.7% and 32.1 to 39.2%, respectively for 1995 and 1996 and the vernolic acid content ranged from 68.9 to 74.7% and 69.1 to 75.6%. A significant positive correlation (r=0.34) between oil content and vernolic acid content indicated that both these characteristics could be improved simultaneously. The highest seed yield was obtained with 100 kg N/ha. A pre-plant-incorporated application of Trifluralin herbicide at 0.5 kg/ha a.i. did not reduce vernonia stand establishment. Seedhead shattering was observed to be a limitation in the evaluated vernonia germplasm. These results indicate that commercial vernonia production in Virginia and other areas in the mid-Atlantic region of United States may be feasible. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Vernonia anthelmintica; Vernonia galamensis; Vernolic acid; Oil content

 Contribution of Virginia State University Agricultural Research Station, Journal Article Series No. 217. The use of any trade names or vendors does not imply approval to the exclusion of other products or vendors that may also be suitable. * Corresponding author. Tel.: + 1-804-524-6723; fax: + 1-804-524-5950. E-mail address: [email protected] (H.L. Bhardwaj)

0926-6690/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 6 - 6 6 9 0 ( 0 0 ) 0 0 0 4 6 - 7

H.L. Bhardwaj et al. / Industrial Crops and Products 12 (2000) 119–124

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1. Introduction During the mid-1950s, the Agricultural Research Service, US Department of Agriculture initiated a plant screening program to identify new and unique plant constituents as sources of

industrial raw materials that would not compete with existing crops. A component of this program focused on finding unusual seed oils such as vernonia [Vernonia anthelmintica (L.) Willd.] with an epoxidized fatty acid because substantial quantities of epoxy oils are used by industry.

Table 1 Performance of ten vernonia genotypes at Petersburg, Virginia for 1994 Entry

Seed heads per plant Mature (%)

AZ94-1 AZ94-2 AZ94-3 AZ94-4 AZ94-5 AZ94-6 AZ94-7 AZ94-8 AZ94-9 A0399

26 36 20 29 23 43 25 37 20 29

Mean CV

29 61

a

Height (cm)

Seed yield (kg/ha)

112 110 126 111 103 83 111 119 115 109

581 806 647 1012 490 766 810 1288 683 880

Immature (%)

bca ab c bc bc a bc ab c bc

74 64 80 71 77 57 75 63 80 71

ab bc a ab ab c ab c a ab

71 25

bc bc a bc c d bc ab a–c bc

110 8

bc bc bc ab c bc bc a bc a–c

796 38

Means followed by same letter, within columns, were not different according to Duncan’s multiple range test (P = 0.05).

Table 2 Performance of vernonia lines for 1995 and 1996 at Petersburg, Virginia Entry

Seed yield (kg/ha)

1995 A0399 AZ95-1 AZ95-2 AZ95-3 AZ95-4 AZ95-5 AZ95-6 AZ95-7 AZ95-8 AZ95-9 AZ95-10 AZ95-11 VX95-1 VX95-2 Mean CV a

599 993 751 1315 516 1394 1019 759 793 781 766 494 902 971 861 32

Seed oil content (%)

1996 cda a–c cd ab d a a–c cd cd cd cd d b–d a–c

1542 1846 1737 1243 1934 1834 1639 1087 1617 1544 1280 1719 1846 1555 1546 35

a a a a a a a a a a a a a a

Mean

1995

1071 1032 1244 1279 1225 1614 1329 923 1205 1162 1023 1106 1374 1263

33.2 36.7 33.1 30.3 33.3 33.8 33.1 35.0 35.1 33.3 31.7 31.1 35.9 35.4

1204 40

a a a a a a a a a a a a a a

33.7 6.4

1996 a–c a a–c c a–c a–c a–c a–c a–c a–c a–c bc ab a–c

32.1 36.6 38.3 38.1 39.2 36.9 38.5 36.8 38.3 32.5 35.3 33.0 36.6 34.0 36.2 7.5

a a a a a a a a a a a a a a

Vernolic acid content of seed oil (%) Mean

1995

32.6 36.9 35.7 34.2 36.2 35.4 35.8 35.9 36.7 32.9 33.5 32.4 36.2 34.7

74.5 72.6 70.5 69.6 68.9 73.1 71.4 71.9 70.8 71.1 71.8 73.9 72.4 74.7

35.0 7.1

a a a a a a a a a a a a a a

71.9 2.1

1996 ab a–d c–e de e a–d a–e a–e b–e a–e a–e a–c a–e a

72.2 74.9 74.7 75.3 74.7 75.5 74.4 69.1 75.6 73.1 73.8 73.1 72.0 71.3 73.6 2.7

Mean a a a a a a a a a a a a a a

73.4 73.8 72.6 72.4 71.8 74.3 72.9 70.5 73.2 72.1 72.8 73.3 72.2 73.0

a a a a a a a a a a a a a a

72.7 3.0

Means followed by same letter, within columns, were not different according to Duncan’s multiple range test (P = 0.05).

H.L. Bhardwaj et al. / Industrial Crops and Products 12 (2000) 119–124 Table 3 Correlation coefficients among vernonia traits grown at Petersburg, Virginiaa Traits

1995

1996

Combined

Seed yield and oil content Seed yield and vernolic acid content Oil and vernolic acid content

−0.05

−0.07

0.10

−0.24

0.04

0.03

−0.01

0.52**

0.34*

a

*, **: Correlation coefficient significantly different from zero at the 5 and 1% level, respectively. Table 4 Effects of fertilizer rates on vernonia yield in Virginia Nutrient

Rate (kg/ha)

Yield (kg/ha)

Nitrogen

50 100 150

945.7 ba 1297.8 a 1300.2 a

Phosphorus

50 100 150

1148.6 a 1198.5 a 1196.5 a

Potassium

50 100 150

1160.0 a 1178.3 a 1205.4 a

a Means followed by the same letter, within each fertilizer, were not different according to Duncan’s multiple range test (P= 0.05).

Vernonia produces high quantities of epoxy fatty acids that are useful in reformulation of oil based (alkyd-resin) paints to reduce emissions of volatile organic compounds that contribute to production of smog (Anonymous, 1989). Other potential markets for epoxy fatty acids include plasticizers, additives to polyvinyl chloride, polymer blends and coatings, and cosmetic and pharmaceutical applications. No other available germplasm containing naturally occurring epoxy oils, with good potential for commercialization, exists in the United States. Present needs are met with petrochemicals or by chemical epoxidation of fats and vegetable oils such as soybean [Glycine max (L.) Merr.]. Initial research was undertaken to evaluate and develop Vernonia anthelmintica germplasm suited

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to American agriculture. A program was also initiated to conduct utilization research on vernonia oil. The breeding and agronomic research led to the development of improved lines, but as a result of lack of seed retention and non-uniform maturity of seed heads, the program was discontinued (Massey, 1971). Even though utilization research indicated potential for success, the lack of vernonia varieties suitable for cultivation in the United States led to the cessation of agronomic and utilization research by the early 1970s (Perdue et al., 1986). Interest in vernonia was rekindled when Vernonia galamensis (Cass.) Less. was discovered in 1964 in Ethiopia (Perdue et al., 1986). Vernonia galamensis is a herbaceous annual plant that is widely distributed in regions of East Africa. This species exhibited increased seed retention compared to V. anthelmintica. The seeds of V. galamensis contained about 42% oil with a 73% vernolic acid content, substantially higher than that of best V. anthelmintica selections (Thompson et al., 1994a). However, short-day response flowering limited the usefulness of this species in the United States. The discovery of a day-neutral germplasm in one accession of V. galamensis ssp. galamensis var. petitiana (Thompson et al., 1994b) greatly improved its potential use. However, this accession (A0399) lacked important characteristics such as seed retention, which limited its usefulness. The main objective of our research efforts was to evaluate the feasibility of vernonia production in mid-Atlantic region of the United States. Specifically, we wanted to evaluate available vernonia germplasm for seed yield, oil content, and oil quality. Preliminary research was also conducted to identify suitable production practices.

2. Materials and methods Field experiments were conducted at the Randolph Farm of the Virginia State University (Latitude 37°-15%N, Longitude 77°-30.8%W). The soil type was Abel sandy loam (Fine Loamy mixed, thermic Aquatic Hapridult). This region is characterized by short days when vernonia starts to flower.

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2.1. Germplasm e6aluation During 1994, nine breeding lines and a bulk population of A0399 were evaluated. Breeding lines with the ‘AZ’ designation were hybrids formed by recombining the day neutral flowering response of A0399, var. petitiana, with the desirable plant growth characteristics of var. ethiopica and other accessions of V. galamensis (Thompson et al., 1994b). The nine progenies (AZ94-1 – AZ949) and A0399 as a check were planted in a greenhouse on 22 April 1994 in flat trays. A commercial potting material, Promix-B, was used as the planting medium. The early-germinating and healthy plants were transplanted to individual cells in speedling trays on 20 May 1994. The seedlings were transplanted to the field on 8 June 1994. A randomized complete block design with four replications was used for field planting. The spacing between plants was 0.3 m and that between rows was 0.9 m. Each plot consisted of four rows with 12 plants per row. All plots received 100 kg/ha each of nitrogen, phosphorus, and potassium. Four plants per plot were harvested to determine the proportion of mature and immature seed heads per plant. The seed yield from mature seedheads of each plot was used to calculate seed yield (kg/ha). A sample of 25 mature seedheads was also taken from each plot. During 1995 and 1996, 11 selections from the United States Water Conservation Laboratory, Phoenix, Arizona, two selections from Virginia, and a check were evaluated. These 14 lines were planted in a randomized complete block design with four replications on 16 May 1995 and 21 May 1996, respectively, at the Randolph Farm of Virginia State University. Each plot consisted of four rows spaced 75 cm apart and 4.2 m long. A total of 1 g of seed was direct-seeded in each individual row. The middle two rows were harvested by hand for yield measurements.

2.2. Fertilizers Acid-delinted seed of A0399 were planted in pots on 28 June 1993, in the greenhouse to obtain enough seedlings for the nitrogen, phosphorus, and potassium field experiment. After planting (14

days), single seedlings were transplanted to individual cells in plastic trays. Vigorous transplants from these cells were transplanted to the field on 21 July 1993 in 28 plots. Each plot consisted of three rows 3 m long and 75 cm apart with 30 cm between plants in the row. The field was lightly irrigated (about 1 cm water) 1 day before transplanting to assist with seedling establishment. These plots were irrigated immediately after transplanting and for the following 2 days with approximately 1 cm water. Three rates each of nitrogen, phosphorus, and potassium (50, 100, and 150 kg/ha) were applied (27 combinations) on 17 August 1993. One plot was treated as a check and did not receive any fertilizer treatment. The field design was a randomized complete block design with two replications (28 plots per replication). A soil sample from this field indicated that residual nitrogen was approximately 14 kg/ha. The experimental area had very high content of P (approximately 200 kg/ha) and high content of K (approximately 140 kg/ha). The organic content and the pH of the experimental area were approximately 1.2 and 6.3, respectively. In this experiment, mature seed heads from the middle row of each plot were harvested in November.

2.3. Herbicides In 1993, the effects of Trifluralin herbicide application on vernonia stand establishment were studied. Two adjacent plots were used for this experiment. In one plot, Trifluralin was applied and preplant-incorporated at a rate of 0.5 kg/ha a.i. In the second plot, only water was used (a completely randomized design with two treatments). In each plot, ten rows spaced 75 cm apart were hand-sown with 50 seeds of A0399 on 13 May 1993. The number of emerged seedlings was recorded on 4 June 1993. In 1995, the effects of Sethoxydim (Poast), a post emergence herbicide for grass weed control, and Fomesafen (Reflex), a post emergence herbicide for broadleaf weed control, were evaluated on 14 vernonia entries in a completely randomized design with two treatments. These herbicides were sprayed over the top with a back-pack manual sprayer, before flowering, at rates recommended for soybean in Virginia

H.L. Bhardwaj et al. / Industrial Crops and Products 12 (2000) 119–124

(0.2 kg/ha a.i. for Poast and 0.3 kg/ha a.i. for Reflex). Only visual observations on foliar damage were recorded to determine whether the herbicide application had caused damage to the plant canopy.

3. Results and discussion

3.1. Germplasm e6aluation Significant variation existed among the entries for plant height, mature and immature seed heads, seed yield, and plant height during 1994 (Table 1). The plant height ranged from 83 to 126 cm. The seed yield ranged from 490 to 1288 kg/ha with a mean of 796 kg/ha. The yield of the check line (A0399) was 880 kg/ha, which was not significantly different from that of the highest yielding entry (AZ94-8), which had a seed yield of 1288 kg/ha. AZ94-6 had a significantly higher percentage of mature seedheads compared to A0399. The 1995–1996 vernonia research evaluating 14 lines (11 from Arizona, two from Virginia, and a standard check), strongly suggests that this unique oilseed plant is adapted to Virginia conditions and it may be feasible to grow this plant in the mid-Atlantic region of the United States. There were indications that fresh-unripened seeds of some selections from Arizona had poor germination. The yield, oil content, and vernolic acid content data are presented in Table 2. The seed yield ranged from 494 to 1394 kg/ha with four lines (AZ95-1, AZ95-3, AZ95-5, and AZ95-6) significantly outyielding A0399 (599 kg/ha) during 1995, indicating that progress has been made to improve vernonia germplasm for yield. The yield of the two Virginia lines (VX95-1 and VX95-2) during 1995, though not significant, was numerically superior to that of A0399. The oil and vernolic acid content in 1995 ranged from 30.3 to 36.7% and 68.9 to 74.7%, respectively. None of the breeding lines differed significantly from A0399 for oil or vernolic acid contents. In 1996, the yield, oil content, and vernolic acid content data indicated a lack of significant variation among the 14 entries for these traits (Table 2). The yield ranged from 1070 to 1934 kg/ha, the oil

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content from 32.0 to 39.2%, and the vernolic acid content from 69 to 76%. Analysis of combined data from 1995 to 1996 (Table 2) indicated a lack of significant variation among the 14 entries for yield and other traits. These production levels compare favorably with the vernonia seed yield of 1200 kg/ha in Zimbabwe (Perdue et al., 1987). Seed shattering continued to be prevalent in the available vernonia germplasm in our tests. However, based on the seed yield of 1546 kg/ha for 1996, the oil content of 36% (Table 2), and the high demand for vernonia oil, commercial vernonia production in Virginia and other areas in the mid-Atlantic region of the United States may be economically feasible. The correlations between various characteristics are presented in Table 3. Correlations between seed yield and oil content, and that between seed yield and vernolic content in the oil were not significant. The correlation between oil content and vernolic acid content in the oil was significant and positive, based on the 1996 data (+ 0.52) and the combined data from 1995 and 1996 (+ 0.34). These results indicate that it might be possible to simultaneously increase the oil yield and vernolic acid yield of V. galamensis.

3.2. Fertilizers The results (Table 4) indicated that highest seed yield was obtained with 100 kg/ha of nitrogen fertilizer rate. The seed yields following 50, 100, and 150 kg/ha of nitrogen fertilizer were 946, 1298, and 1300 kg/ha, respectively. The residual nitrogen in this field was approximately 14 kg/ha. Therefore, nitrogen requirement for vernonia is approximately 114 kg/ha. The results also showed that vernonia seed yield did not increase when P and K rates were increased from 50 to 100 or 150 kg/ha. Based on this data, it is not possible to determine the lower acceptable rates for P and K fertilizers. However, P and K fertilizers at the rates of approximately 50 kg/ha may be suitable.

3.3. Herbicides The preplant-incorporated application of Trifluralin had no harmful effects on vernonia stand

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establishment (data not shown). This observation is similar to the results in Oregon (Roseberg, 1997). Therefore, trifluralin seems to be an excellent candidate for registration for weed control in vernonia. Visual estimates of foliar injury indicated that selections differed in their tolerance to Poast and Reflex herbicides (Data not shown). Foliar injury following treatment with Reflex was considered unacceptable, and, thus, unsuitable for weed control in vernonia. Further research is needed for Poast herbicide to identify precise application times and rates. References Anonymous, 1989. Vernonia, new industrial oil crop. Agric. Res. 37 (4), 10 – 11.

.

Massey, J.H., 1971. Harvesting Vernonia anthelmintica (L.) Willd. to reduce seed shattering losses. Agron. J. 63, 812. Perdue, R.E. Jr, Carlson, K.D., Gilbert, M.G., 1986. Vernonia galamensis, potential new crop source of epoxy acid. Econ. Botany 40 (1), 54 – 68. Perdue, R.E. Jr, Jones, E., Nyati, C.T., 1987. Vernonia galamensis: a promising new industrial crop for the semi-arid tropics and subtropics. In: Wickens, G.E., Haq, N., Day, P. (Eds.), New Crops for Food and Industry. Chapman and Hall, New York, pp. 197 – 207. Roseberg, R.J., 1997. Herbicide tolerance by vernonia grown in temperate zone. Ind. Crops Prod. 6, 89 – 96. Thompson, A.E., Dierig, D.A., Kleiman, R., 1994a. Variation in Vernonia galamensis flowering characteristics, seed oil and vernolic acid contents. Ind. Crops Prod. 3, 175 – 183. Thompson, A.E., Dierig, D.A., Johnson, E.R., Dahlquist, G.H., Kleiman, R., 1994b. Germplasm development of Vernonia galamensis as a new industrial oilseed crop. Ind. Crops Prod. 3, 185 – 200.