There are a number of specialty corns that can be successfully grown in Ohio, including high oil, high lysine, and waxy corn. Most of these are genetic variants of the widely produced yellow dent corn which is produced and marketed primarily as grain. Producing specialty grain may allow corn growers to find a niche in the market and obtain significant premiums. They can also be used on farm reducing feed costs significantly. Because these corns may offer greater economic returns than normal corn they have been referred to as "value enhanced corns"; and grain produced by these specialty corns has been referred to as value enhanced grain. Specialty corns offer several advantages over other specialty crops as alternatives to traditional field crops. They can be grown with similar cultural practices and planted and harvested with the same equipment used in grain corn production. If grown for a specialty grain market that dries up, they generally can be used for other purposes, i.e. used directly as livestock feed on the farm or sold as normal grain to the elevator.
Although there is widespread interest in growing various specialty corns for value enhanced grain production, there is limited information comparing the quality attributes of specialty grains with those of normal yellow dent corn. There is also little or no information available on the production and marketing of specialty corns. Hybrid selection of specialty corn types is complicated by a lack of information on their performance under different environmental conditions. Some seed companies conduct performance tests which compare specialty hybrids and normal dent hybrids. However such comparisons often do not include popular high yielding normal corn hybrids primarily grown for grain. Moreover these trials are usually performed in the western Corn Belt so information on hybrid response to stress conditions and various pest problems characteristic (such as gray leaf spot) of the eastern Corn Belt is limited.
Comprehensive information relating to the value added characteristics of specialty corns, including amino acid and fatty acid profiles, is not readily available. Such information is needed to optimize the potential end uses of specialty grains. In addition to information on total protein, oil and starch content of grain, end users want more specific details on the quality of the proteins and fats in grain. Information on levels of amino acids (such as lysine, methionine, cystine, and tryptophan) and fatty acids (such as linoleic acid and oleic acid) are needed so specialty grains can be used as alternative and more profitable ingredients in livestock feeds as well as in other food and industrial products. Various individual amino acids are important in livestock feeding (lysine to swine, sulfur containing methionine and cystine to poultry). Similarly, the relative concentration of essential monounsaturated fatty acids (such as oleic acid) and polyunsaturated fatty acids (such as linolenic acid) may affect end uses of specialty grains. In the future, corn oil high in palmitic acid may be in demand for margarine production, requiring less chemical processing whereas cooking oils derived from corn high in oleic acid would be beneficial to consumers' health. The fatty acid profile of corn grain may also be a consideration in animal feeds by influencing the storability and flavor of meat.
In 1997-1998 we initiated an evaluation of specialty corns supported in part by the Ohio Corn Marketing Board to (1) to collect information on grain quality attributes associated with specialty corns, i.e. oil, protein, starch, fatty acids and amino acids and (2) to evaluate the agronomic performance of specialty corns.
Field tests were conducted in 1997 to compare the grain quality and agronomic performance of high oil corn, waxy corn, high lysine corn, and normal dent corn. Pfister Hybrid Corn Company provided five TC Blends® (SuperKernoils) used in TopCross® high oil grain production and their respective male fertile, low oil grain parent checks. These five SuperKernoils contained Pfister pollinator "19". Waxy corn hybrids were provided by DeKalb Genetics and Pioneer HiBred Int'l., Inc. High lysine hybrids were provided by the Crow Seed Company. In addition to the five normal Pfister hybrids, DeKalb 604 (DK604) and Pioneer 3394 (P3394) were also included as check hybrids because of their high grain yield potential, adaptability, and popularity. Based on previous results from the Ohio Corn Performance Trials (which have compared commercial corn hybrids for oil and protein content), we knew that grain of P3394 was characterized by average oil content. Strip plots were established at The Ohio State University–Ohio Agricultural Research and Development Center (OARDC) in Wooster. The high lysine and waxy corn fields were nearly adjacent to each other and the high oil corn field was in close proximity to the latter two fields. Each specialty corn and normal hybrid was planted in strip plots four rows wide (30-inch row spacings) and approximately 200 feet in length.
To minimize possible pollen contamination from neighboring male fertile check hybrids as well as any nearby normal corn, the TC Blend plots were planted in isolation approximately 100 feet from normal corn hybrids. A 100-foot buffer separating the normal corn from the TC Blends was planted with excess TC Blend seed to minimize foreign pollen contamination. Plots were also planted with TC Blend seed as border (20-50 feet) on all sides of the isolation field. The only nearby foreign pollen source was that of the male fertile grain parent plots. In the waxy and high lysine fields, corn hybrids were planted in twelve 30-inch row plots, 200 feet in length. The experimental design was a randomized block with three replicated blocks.
The same set of high oil TC Blends and grain parent check hybrids used in the specialty corn evaluation at OARDC in Wooster was also planted in a multicounty study performed at sites in Clark, Franklin, Logan, Licking, Madison, Wayne and Wood counties. Each TC Blend and normal hybrid was planted in strip plots at least four rows wide (30-inch row spacings) and 200 feet in length. The same isolation procedures described above for the high oil corn were used at each of the seven test sites. At all locations, the only nearby foreign pollen source was that of the male fertile grain parent plots. Nutrient, insect, and weed management strategics appropriate for minimizing crop stress were followed at each location.
Shortly before harvest ten ears were randomly selected from plants in a 50-foot length of row in the center of each plot. These ears were shelled and a subsample of grain from each plot was submitted to the Iowa State Grain Quality Laboratory and the Optimum® Quality Grains Laboratory (Urbandale, IA) for analysis of various grain quality attributes. Oil, protein, and starch content were determined by near infrared transmittance analysis (NIR). Metabolizable energy (M.E.) for non-ruminants was estimated by calculation. Amino acid content and fatty acid profiles were determined using liquid gas chromatography. Final plant stand, numbers of plants stalk lodged (stalk breakage below the ear), and barren or with nubbin ears were recorded at harvest. Plots were harvested by combine and grain yields were adjusted to 15.5% moisture.
Comparisons of High Oil, High Lysine, Waxy, and Normal Corn, Wooster, 1997
Agronomic Performance: Although the normal corn hybrids generally exhibited the highest grain yield potential, there were specialty corn hybrids of each type with yields comparable to those of normal hybrids (Table 1). Yields of the normal corn hybrids ranged from 125 to 167 Bu/A, whereas yields ranged from 133 to 156 Bu/A for the High Oil TC Blends, 112 to 147 Bu/A for the high lysine corn hybrids, 113 to 141 Bu/A for the waxy corn hybrids. Grain moisture at harvest was generally greater for the high oil TC Blends than the other specialty corns and the the normal checks. Stalk lodging was significantly greater in the high lysine hybrids than in the TC Blends, normal and waxy corns.
|Table 1. Agronomic performance of normal, high oil, high lysine, and waxy corns, Wooster, OH 1997|
|Type||Yield (bu/A)||% Moisture||% Lodging|
Grain Quality Attributes: The oil content in TopCross grain from the TC Blends was 3 to 4 percentage points higher than in grain from waxy, high lysine, and normal corn hybrids (Table 2). The range in protein levels among the specialty corns and normal checks was comparable. Metabolizable energy levels were higher, whereas starch levels were lower in TopCross high oil grain compared to grain of the waxy, high lysine and normal corn hybrids.
|Table 2. Select grain quality attributes of normal, high oil, high lysine, and waxy corn, Wooster, OH 1997|
|Type||% Oil||% Protein||% Starch||M.E. (Kcal/lb)|
Fatty acid profiles of normal and specialty corn grain are shown in Table 3. Stearic and oleic acid levels were greater and linoleic and linolenic acid levels lower in TopCross high oil grain than in the normal corn and the other specialty corn grain. Table 4 provides a comparison of the amino acid content of grain from the normal and specialty corns. Levels of several important amino acids differed among corn types. Lysine levels were greatest in the high lysine corn (0.33-0.37%) followed by the high oil TC Blends (0.31-0.34%). Methionine levels were higher in high oil (0.18-0.21) and waxy corn (0.18-0.20) than in other types. Levels of taurine, serine, alanine, and phenalanine were higher in high oil than high lysine corn. Levels of threonine, phenalanine, and glycine were greater in high oil than normal corn.
|Table 3. Comparison of normal, high oil, high lysine, and waxy corn grain for % fatty acids, Wooster, OH 1997|
|Type (Saturation)||% Fatty Acid Composition|
|Palmitic (16:0)||Stearic (18:0)||Oleic (18:1)||Linoleic (18:2)||Linolenic (18:3)||Arachidic (20:0)|
|Table 4. Comparison of normal, TopCross high oil, high lysine, and waxy corn grain for amino acids, Wooster, Ohio 1997|
|Type||Amino Acid Composition*|
|*Expressed on a dry weight basis|
Comparison of High Oil and Normal Corn, 1997 Multi-County Evaluation
Agronomic Performance: Grain yields of the five TC Blends, averaged across seven test sites (Clark, Franklin, Logan, Licking, Madison, Wayne and Wooster), ranged from 137 to 156 Bu/A compared to normal parent check yields that ranged from 150 to 166 Bu/A (Table 5).To determine if variation in TC Blend and normal hybrid performance was significantly different, data from the seven county tests were combined and compared as a randomized complete block design with seven replicated blocks. A comparison of agronomic performance and grain composition from the combined data is presented in Table 5. Two of the five TC Blends produced yields that were significantly lower that their respective grain parents. Grain moisture of two TC Blends was significantly greater than that of the respective normal parents. Stalk lodging and % of plants barren or with nubbin ears were similar for the TC Blends and normal hybrids (data not shown).
Grain Quality Attributes: Oil levels in TopCross high oil grain from SuperKernoils averaged 3.6 percentage points greater than those of the normal parents. TopCross high oil grain oil levels also differed significantly—varying by 0.7 percentage points among SuperKernoils. Differences in grain oil content among the normal hybrids were not significant. Metabolizable energy was higher, whereas starch levels was lower in TopCross grain compared to normal grain.
Table 6 shows fatty acid profiles of normal and TopCross grain. Palmitic acid levels were generally similar for normal and TopCross and normal grain. Stearic, oleic acid, and arachidic acid levels were higher, whereas linoleic and linolenic acid levels were lower in TopCross grain compared to normal grain.
|Table 5. Comparison of high oil TC Blends with normal corn hybrids at seven Ohio locations, 1997|
|Type||Brand/Hybrid||Yield Bu/A||% Moist||Final Stand||Grain Composition on a Dry Wt Basis*|
|% Oil||% Protein||% Starch||M.E. (Kcal/lb)|
|High-Oil TC Blends||Pfister SK3049-19||144||23.2||24600||7.5||8.5||67.2||1858|
|Normal (Parent Checks)||Pfister 3049||156||22.7||27410||4.5||8.3||71.2||1785|
|*Oil, Protein and Starch by NIT; M.E. by calculation.
(M.E. is Non-Ruminant Metabolizable Energy Content)
|Table 6. Comparison of normal and TopCross® high oil corn grain for fatty acids, seven Ohio locations, 1997|
|Type||Brand/Hybrid||% Fatty Acids|
|High-Oil TC Blends||Pfister SK3049-19||11.8||2.4||32.5||50.1||0.9||0.43|
|Normal (Parent Checks)||Pfister 3049||11.9||2.0||24.4||59.9||1.3||0.29|
The amino acid composition of TopCross and normal grain is shown in Table 7. Levels of lysine, methionine, asparagine, glycine, alanine, valine, arginine, cystine and threonine were higher in TopCross high oil grain than in normal corn grain. Lysine levels ranged from 0.34 to 0.36% in TopCross high oil grain compared to 0.29 to 0.31% in normal corn. Methionine levels ranged from 0.22 to 0.24% in TopCross grain compared to 0.18 to 0.22% in normal corn.
|Table 7. Comparison of normal and TopCross high oil corn grain for amino acids at seven Ohio locations, 1997|
|Type||Brand/Hybrid||Amino Acid Composition*|
|High Oil TC Blends||Pfister SK3049-19||0.17||0.62||0.35||0.41||1.71||0.88||0.41||0.70||0.27||0.48||0.22||0.33||1.11||0.29||0.46||0.30||0.34||0.47||0.06|
|Normal (Parent Checks)||Pfister 3049||0.17||0.56||0.31||0.39||1.59||0.83||0.36||0.63||0.24||0.45||0.18||0.30||1.05||0.25||0.44||0.29||0.30||0.42||0.06|
|*Expressed on a dry weight basis|
Field studies conducted in 1997-1998 indicate that certain high oil TC Blends, waxy and high lysine hybrids are available with grain yields comparable to normal hybrids. Grain moisture at harvest was comparable for the normal, waxy and high lysine corn hybrids but the grain moisture of TopCross grain from the TC Blends was higher for certain high oil blends compared to their respective normal grain parents. Stalk lodging was consistently greater in the high lysine corn hybrids than in high oil TC Blends, waxy corn hybrids and normal corn hybrids. TopCross grain exhibited oil levels about three percentage points higher than grain from the normal check hybrids. Stearic and oleic acid levels were greater and linoleic and linolenic acid levels lower in TopCross grain than in the normal corn and the other specialty corn grain. Fatty acid ranges were generally similar in the waxy, high lysine and normal corn grain. The range in protein levels among the specialty corns and normal checks was comparable but levels of several important amino acids differed among the specialty and normal corns. Metabolizable energy was significantly higher, whereas starch levels were lower in TopCross grain compared to grain of waxy, high lysine and normal corn hybrids.
Acknowledgements: We wish to thank the Ohio Corn Marketing Program for funding this evaluation. We are also grateful to Optimum Quality Grains, L.L.C. for the numerous grain quality analyses they have provided.
TC-Blend®, TopCross®, and Optimum® are registered trademarks of Optimum Quality Grains, L.L.C.. SuperKernoil is a trademark of the Pfister Corn Hybrid Company.