WET MILLING CHARACTERISTICS OF TEN LINES FROM THE GERMPLASM ENHANCEMENT OF MAIZE PROJECT O. R. TABOADA-GAYTAN1, L. M. POLLAK2, L. JOHNSON3, S. FOX3, AND S. DUVICK41Agronomy Dept., Iowa State University, Ames, Iowa. 2USDA-ARS Corn Insects and Crop Genetics Research Unit, Ames, IA . 3 Center for Crops Utilization Research, Iowa State University, Ames, Iowa. 4 USDA-ARS Plant Introduction Research Unit, Ames, Iowa.INTRODUCTIONCorn (Zea mays L.) is the main crop in the United States not only due to the area planted but also to the enormous amount of uses and products that can be obtained from the corn kernels. In 2004, corn production was estimated at 11,807.2 million bushels with average yields of 162 bushels/acre.The use of corn to produce food and for industrial purposes has been increasing during the last few years. In fact, in 2004, 22.6% of the total volume was processed to produce starch, sweeteners, and ethanol and other fermentation products, mainly through the wet-milling process.Starch is the most important product obtained from wet milling. However, production of high-starch-yielding hybrids is still a developing objective of corn breeding programs. Additionally, characteristics that are important for the corn processing industry, such as millability and composition of the recovered fractions, need to be studied.This study is focused on the use of exotic materials to obtain useful breeding lines containing both adapted and exotic characteristics. MATERIALS AND METHODS Genetic MaterialsTen lines from the GEM project (Fig. 1) were used in this study. The lines have 25% exotic genetic background from Argentina (AR16035:S19-285-1-B and AR16035:S19-227-1-B), Chile (CH05015:N15-182-1-B and CH05015:N15-143-1-B), Cuba (CUBA117:S1520-562-1-B and CUBA117:S1520-153-1-B), Florida (FS8B(T):N1802-32-1-B and FS8B(T):N1802-35-1-B), and Uruguay (UR13085:N0215-11-1-B and UR13085:N0215-14-1-B). Seed of the lines was produced in Ames, IA, in the Summer of 2003 by self pollination and bulked at harvest.Compositional CharacteristicsNear-Infrared Transmittance (NIR-T) technology was used to estimate moisture, starch, protein, and oil contents of bulked whole kernels from each line by using a FOSS Infratec 1241 Grain Analyzer (Tecator, Hoganas, Sweden).Wet-Milling CharacteristicsTwo samples from each line were analyzed in the laboratory by using the 100 g. modified wet-milling procedure (Singh et al, 1997). This procedure (Fig. 2) yields starch, gluten, fiber, germ, and steepwater fractions. Moisture content of the recovered fractions was determined in triplicate by using the AOAC method 14.004 (AOAC, 1984).Statistical AnalysisProc ANOVA and Proc CORR of SAS (SAS Institute, Cary, NC) were used to determine statistical differences and correlations among different values, respectively.RESULTSCorn lines from the GEM project were originally selected for grain yield as testcrosses and then evaluated for wet-milling properties. For this project ten lines were chosen on the basis of starch yield. The highest and the lowest starch-yielding lines for each of the five different germplasm sources (Argentina, Chile, Cuba, Florida, and Uruguay) were selected. The compositional characteristics, obtained from the NIR-T analysis, of the lines are shown in Table 1.The wet-milling characteristics of the lines presented a great variation and statistical differences (p 0.0001) were found among the recovered milling fractions. Total solids recovered did not show statistical differences (Table 2).AR16035:S19-227-1-B, CUBA117:S1520-562-1-B, and CH05015:N15-182-1-B presented better starch yield than the inbred line B73. Correlations among the values of the compositional and wet-milling characteristics (Table 3) varied largely but followed the same pattern reported in previous studies (Fox et al, 1992; Singh et al, 2001)Table 1. Compositional Characteristics of Ten Lines from the GEM ProjectTable 2. Wet-Milling Characteristics of Ten Lines from the GEM ProjectTable 3. Correlation Coefficients Between Compositional and Wet-Milling Characteristics of Ten Lines from the GEM ProjectCONCLUSIONSSome lines with exotic genetic background have better wet-milling characteristics, related to starch yield, than the Corn Belt inbred line B73.The results indicate that the use of exotic corn germplasm in a wet milling breeding program will enhance available genetic diversity.REFERENCESAOAC. 1984. Official Methods of Analysis of the Association of Official Analytical Chemists. 14th ed. Method 14.004 The Association: Washington, DC.Fox, S. R., L. A. Johnson, C. R. Hurburgh, C. Dorsey-Redding, and T. B. Bailey. 1992. Relations of Grain Proximate Composition and Physical Properties to Wet-Milling Characteristics of Maize. Cereal Chem. 69(2):191-197.Singh, S. K., L. A. Johnson, L. M. Pollak, S. R. Fox, and T. B. Bailey. 1997. Comparison of Laboratory and Pilot-Plant Corn Wet-Milling Procedures. Cereal Chem. 74(1):40-48.Singh, S. K., L. A. Johnson, L. M. Pollak, and C. R. Hurburgh. 2001. Compositional, Physical, and Wet-Milling Properties of Accessions Used in the Germplasm Enhancement of Maize Project. Cereal Chem. 78(3):330-335.CONTACT INFORMATIONLinda M. Pollak: Professor in Charge. 1405 Agronomy Hall, Iowa State University, Ames, Iowa, 50011. Phone: (515) 294-7831. E-mail: lmpollak@iastate.edu.1, 2 = Compositional and recovered starch, respectively.

PEDIGREECOMPOSITIONAL CHARACTERISTICS (db)STARCHPROTEINOILAR16035:S19-285-1-B70.1211.414.35AR16035:S19-227-1-B69.6510.944.71CH05015:N15-182-1-B69.7611.884.00CH05015:N15-143-1-B68.2312.714.47CUBA117:S1520-562-1-B69.0612.354.59CUBA117:S1520-153-1-B68.8212.354.82FS8B(T):N1802-32-1-B69.4111.535.06FS8B(T):N1802-35-1-B70.7111.064.35UR13085:N0215-11-1-B71.0611.413.76UR13085:N0215-14-1-B69.5312.124.12B73 (Singh et al, 2001)69.7011.904.30

PEDIGREEWET-MILLING FRACTIONS (% of db)STARCHFIBERGERMGLUTENSWATERTSR (%)AR16035:S19-285-1-B61.61cd11.03d4.00f17.87b5.29c99.80aAR16035:S19-227-1-B64.25a10.06g5.20d14.98d5.22cd99.70abCH05015:N15-182-1-B62.48bc10.08g4.53e17.36bc5.10de99.54abCH05015:N15-143-1-B56.40g10.69ef7.54a19.50a5.51b99.64abCUBA117:S1520-562-1-B63.14b10.54f4.19f16.88c5.05e99.79aCUBA117:S1520-153-1-B60.98de10.87de5.01d17.22bc5.33c99.40bFS8B(T):N1802-32-1-B60.67e10.18g6.51b16.73c5.78a99.87aFS8B(T):N1802-35-1-B59.08f12.57e5.69c17.47bc4.97e99.77abUR13085:N0215-11-1-B60.90de13.56a3.60g16.77c5.10de99.91aUR13085:N0215-14-1-B61.91c11.37c4.71e16.84c5.06e99.88aB73 (Singh et al, 2001)62.4011.405.1011.40----------------SWATER = Steepwater Yield, TSR = Total Solids Recovery. a-g = Values with different letter on the same column are statistically different at p=0.05

STARCH1PROT.OILSTARCH2FIBERGERMGLUTENSWATERSTARCH------------0.7823-0.56700.21220.7068-0.5671-0.3415-0.4900PROT.-----------0.0683-0.3449-0.27360.24890.58950.1712OIL-----------0.0149-0.60910.5253-0.15450.6553STARCH------------0.2988-0.6792-0.8299-0.3471FIBER------------0.33350.0865-0.4497GERM-----------0.42060.6412GLUTEN-----------0.2137-SWATER-----------

outcrossing