Burleson County Research Articles

Mineralogy and Geochemistry of the Main Glauconite Bed in the Middle Eocene of Texas: Paleoenvironmental Implications for the Verdine Facies

The Main Glauconite Bed (MGB) is a pelleted greensand located at Stone City Bluff on the south bank of the Brazos River in Burleson County, Texas. It was deposited during the Middle Eocene regional transgression on the Texas Gulf Coastal Plain. Stratigraphically it lies in the upper Stone City Member, Crockett Formation, Claiborne Group. Its mineralogy and geochemistry were examined in detail, and verdine facies minerals, predominantly odinite, were identified. Few glauconitic minerals were found in the green pelleted sediments of the MGB. Without detailed mineralogical work, glaucony facies minerals and verdine facies minerals are easily mistaken for one another. Their distinction has value in assessing paleoenvironments. In this study, several analytical techniques were employed to assess the mineralogy. X-ray diffraction of oriented and un-oriented clay samples indicated a clay mixture dominated by 7 and 14Å diffraction peaks. Unit cell calculations from XRD data for MGB pellets match the odinite-1M data base. Electron microprobe analyses (EMPA) from the average of 31 data points from clay pellets accompanied with Mössbauer analyses were used to calculate the structural formula which is that of odinite: Fe3+ 0.89 Mg0.45 Al0.67 Fe2+ 0.30 Ti0.01 Mn0.01) Σ = 2.33 (Si1.77 Al0.23) O5.00 (OH)4.00. QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) data provided mineral maps of quantitative proportions of the constituent clays. The verdine facies is a clay mineral facies associated with shallow marine shelf and lagoonal environments at tropical latitudes with iron influx from nearby runoff. Its depositional environment is well documented in modern nearshore locations. Recognition of verdine facies clays as the dominant constituent of the MGB clay pellets, rather than glaucony facies clays, allows for a more precise assessment of paleoenvironmental conditions.

Effect of 1-MCP on Boll Development and Subtending Leaves of Cotton (<i>Gossypium hirsutum</i> L.) Plants

Ethylene regulates multiple physiological processes in cotton (Gossypium hirsutum L.) ranging from square and boll abscission to senescence. This field study investigated the effect of an ethylene inhibiting compound 1-methylcyclopropene (1-MCP) on boll development and the corresponding subtending leaves. The study was conducted in 2011 and 2012 at the Texas A & M Agri-LIFE Research Farm in Burleson County, TX. The study consisted of two rates of 1-MCP (0 and 10 g a.i. ha-1) applied at one and two weeks after first flower. Boll development and subtending leaves were studied on the tagged flowers during the growing season. 1-MCP treatment increased cotton boll weight at 20 days after flowering. This study showed that 1-MCP-treated subtending leaves exhibited decreased membrane damage and lipid peroxidation, and higher chlorophyll content and photosynthetic efficiency at 20 to 30 days after flowering. The healthier state of subtending leaves should have provided more carbohydrates for the fruits which could partially explain the reason for the increased boll weight. However, this beneficial effect of 1-MCP did not last to the end of the growing season and failed to result in a yield increase ultimately. Multiple applications or extending effective duration of 1-MCP is desirable to enhance the activity of 1-MCP to make a significant difference in cotton yield.

Effect of 1-MCP on Cotton Plants under Abiotic Stress Caused by Ethephon

Many environmental stress factors have been identified to increase square and boll abscission and thus result in reduced cotton yield. Under stress conditions, ethylene is elicited. Ethylene peaks before abscission to promote the formation of the abscission layer and plays a major role in early season square and boll abortion in cotton (Gossypium hirsutum L.). In addition, ethylene stimulates the leaf senescence process. Thus, it is desirable to protect plants from ethylene-induced fruit loss and premature leaf senescence under stress conditions. The objective of this study was to evaluate the ability of 1-methylcyclopropene (1-MCP) to protect cotton plants against abiotic stress caused by ethephon (ethylene promoting effect). Field studies using a randomized complete block design with four replications were conducted in 2010 and 2011 at Texas A&M AgriLIFE Research Farm in Burleson County, TX. Eight treatments that consisted of two 1-MCP rates (0 and 10 g a.i. ha-1) in combination with four ethephon rates (0, 146, 292, 438 mL&middotha-1) were imposed at the first flower (FF) stage of the development. 1-MCP increased plant height and number of main stem nodes in both years. In addition, 1-MCP-treated plants exhibited greater membrane integrity and increased photosystem II quantum efficiency and thus delayed senescence in both years. These potentials for yield increase were realized in 2011 with 1-MCP treatment exhibiting a higher lint yield. In 2012, although 1-MCP treatment increased number of open fruit and open fruit weight per plant significantly, no significant lint yield increase was detected.

Eligibility Testing at 41BU75, Burleson County, Texas

Eligibility Testing at 41BU75, Burleson County, Texas

Frequency and Diversity of Fungal Genera Contaminating the External Body Parts of Leaffooted Bug, Leptoglossus phyllopus (Heteroptera: Coreidae)

Coreid bugs and in particular species in the genus Leptoglossus are considered insects pests of economic importance and have been shown to vector plant pathogens especially fungi. Leaffooted bugs, Leptoglossus phyllopus (L.), were collected from pecan, Carya illinoinensis (Wangenheim) K. Koch, Gaura parviflora Dougl., pomegranate, Punica granatum L., and Sorghum bicolor (L.) Moench, fields in Brazos and Burleson counties, Texas in 2008 and 2009. A number of genera of fungi, including Alternaria spp., Bipolaris spp., Claviceps spp., Colletotrichum spp., Curvularia spp., Fusarium spp., Fusicladium effusum, Aspergillus spp., Rhizopus spp., smut and several unidentified spores were found adhering to the external body parts of these insects. Several of these fungal genera contain species that are pathogenic to sorghum and pecan on which leaffooted bugs are considered pests. In both years, Alternaria spp. was the most frequently recovered fungal species. In collection areas such as pecan orchards or from G. parviflora growing close to pecan trees, higher amounts of Fusicladium effusum, causal agent of pecan scab, a very economically important disease, were found contaminating the external body parts of these bugs. Thus, these mobile insects have the potential to passively transmit fungal diseases from plant-to-plant, between fields or orchards and different crops, plant hosts, and habitats.

Testing and Data Recovery Excavations at 41BU51, Burleson County, Texas

Prewitt and Associates, Inc. (PAI), conducted archeological testing and data recovery excavations at prehistoric site 41BU51 in Burleson County, Texas, for the Texas Department of Transportation, Environmental Affairs Division, in three phases of investigation. The first phase of testing, conducted in Spring 2003, resulted in the discovery of a single human burial as well as diagnostic artifacts ranging from the Archaic period through the Late Prehistoric period. A second phase of testing was conducted to search for additional burials in January 2004. This work resulted in the discovery of three additional burials and two isolated human bones. Finally, data recovery to remove the human remains was conducted in June 2007. This report describes all three phases of work.

Indicators of Last Effective Boll Population and Harvest Aid Timing in Cotton

Maintaining profitable and sustainable production of cotton (Gossypium hirsutum L.) relies on improvements in management. The objective of this study was to determine the proper defoliation timing to optimize lint yield and fiber quality through calculating heat unit (HU; DD15.5) accumulation beyond cutout, defined as five nodes above white flower (NAWF = 5). Experiments were conducted in Burleson County, Texas, in 2003 and 2004, on a Weswood silt loam soil (fine‐silty, mixed, superactive, thermic, Udifluventic Halplustepts). Treatments were applied in a split‐plot arrangement using a randomized complete block design with four replications. The main plots consisted of three nodal positions (NAWF = 3, 4, and 5) and the five subplots were HUs (361, 417, 472, 528, and 583) accumulated beyond the corresponding nodal positions (NAWF), at which time a tank‐mix of harvest aids was applied. Immediately before defoliation, 10 plants plot−1 were evaluated for percent open boll (POB) and nodes above cracked boll (NACB). Lint yield was detrimentally impacted in south central Texas when defoliation was initiated at 472 HUs beyond NAWF = 5. Defoliation at 60 POB resulted in as much as 29% more lint yield than defoliation based on the current benchmark of NAWF = 5 plus 472 HUs. This finding suggests NAWF = 5 is neither an indicator of the last effective flower population in all production locations, nor a proper guide for timing cutout on which end‐of‐season management decisions should be based in south central Texas.

Timing of Maturity in Ultra‐Narrow and Conventional Row Cotton as Affected by Nitrogen Fertilizer Rate

Ultra‐narrow row (UNR) systems and N fertilizer can influence cotton (Gossypium hirsutum L.) crop maturation. Study objectives were to measure impacts of UNR systems and N fertilizer rates on cotton maturation and to identify mechanisms by which these effects occurred. The location was Burleson County, Texas. In the split plot design, whole plots were N rates of 0, 50, 101, and 151 kg ha−1. Split plots were 19‐, 38‐ (both UNR), and 76‐cm (conventional row, CR) row spacings with 296,600, 195,400, and 136,300 plants ha−1, respectively. Thirty, 60, and 85% harvestable seedcotton each occurred 1.5 to 2.9 d earlier in UNR than CR spacings. First boll set occurred 1 d later in 19‐cm than in wider row spacings. Boll set rate m−2 was greater in 19‐ than 76‐cm row spacing during a 5‐d flowering period shortly after first boll set, but did not differ by row spacing during three flowering periods thereafter. The percentage first position bolls was lower with wider row spacing, suggesting greater potential for concurrent boll set at multiple sites on individual plants. Eventual development of nonfirst position fruiting sites in 76‐cm row spacing may have contributed to confinement of faster boll set in 19‐cm row spacing to early bloom. Nitrogen rates did not affect the timing of 30, 60, or 85% harvest. Reductions in bolls plant−1 were counteracted by slower boll set rates with lower N. The limited observed interactions of N and row spacing do not suggest advantages from suboptimal N rates in UNR cotton.

Timing of Maturity in Ultra-Narrow and Conventional Row Cotton as Affected by Nitrogen Fertilizer Rate

Ultra-narrow row (UNR) systems and N fertilizer can influence cotton (Gossypium hirsutum L.) crop maturation. Study objectives were to measure impacts of UNR systems and N fertilizer rates on cotton maturation and to identify mechanisms by which these effects occurred. The location was Burleson County, Texas. In the split plot design, whole plots were N rates of 0, 50, 101, and 151 kg ha−1. Split plots were 19-, 38- (both UNR), and 76-cm (conventional row, CR) row spacings with 296,600, 195,400, and 136,300 plants ha−1, respectively. Thirty, 60, and 85% harvestable seedcotton each occurred 1.5 to 2.9 d earlier in UNR than CR spacings. First boll set occurred 1 d later in 19-cm than in wider row spacings. Boll set rate m−2 was greater in 19- than 76-cm row spacing during a 5-d flowering period shortly after first boll set, but did not differ by row spacing during three flowering periods thereafter. The percentage first position bolls was lower with wider row spacing, suggesting greater potential for concurrent boll set at multiple sites on individual plants. Eventual development of nonfirst position fruiting sites in 76-cm row spacing may have contributed to confinement of faster boll set in 19-cm row spacing to early bloom. Nitrogen rates did not affect the timing of 30, 60, or 85% harvest. Reductions in bolls plant−1 were counteracted by slower boll set rates with lower N. The limited observed interactions of N and row spacing do not suggest advantages from suboptimal N rates in UNR cotton.

Detection and Evolution of Resistance to the Pyrethroid Cypermethrin in <I>Helicoverpa zea</I> (Lepidoptera: Noctuidae) Populations in Texas

The bollworm, Helicoverpa zea (Boddie), is a key pest of cotton in Texas. Bollworm populations are widely controlled with pyrethroid insecticides in cotton and exposed to pyrethroids in other major crops such as grain sorghum, corn, and soybeans. A statewide program that evaluated cypermethrin resistance in male bollworm populations using an adult vial test was conducted from 2003 to 2006 in the major cotton production regions of Texas. Estimated parameters from the most susceptible field population currently available (Burleson County, September 2005) were used to calculate resistance ratios and their statistical significance. Populations from several counties had statistically significant (P < or = 0.05) resistance ratios for the LC(50), indicating that bollworm-resistant populations are widespread in Texas. The highest resistance ratios for the LC(50) were observed for populations in Burleson County in 2000 and 2003, Nueces County in 2004, and Williamson and Uvalde Counties in 2005. These findings explain the observed pyrethroid control failures in various counties in Texas. Based on the assumption that resistance is caused by a single gene, the Hardy-Weinberg equilibrium formula was used for estimation of frequencies for the putative resistant allele (q) using 3 and 10 microg/vial as discriminatory dosages for susceptible and heterozygote resistant insects, respectively. The influence of migration on local levels of resistance was estimated by analysis of wind trajectories, which partially clarifies the rapid evolution of resistance to cypermethrin in bollworm populations. This approach could be used in evaluating resistance evolution in other migratory pests.

Nitrogen Fertilization and Yield of Cotton in Ultra‐Narrow and Conventional Row Spacings

Nitrogen fertilizer requirements of ultra‐narrow row (UNR) cotton (Gossypium hirsutum L.) are not well established, and lint yield of UNR relative to conventional‐row (CR) cotton has been variable. Objectives of this study were to compare UNR and CR N requirements based on lint yield, fiber quality, and plant architecture, and to compare the yield potential of UNR and CR cotton. The location was the Texas Agricultural Experiment Station Farm, Burleson County, TX. Treatments were N fertilizer rates of 0, 50, 101, and 151 kg ha−1 and row spacings of 19, 38 (both UNR), and 76 cm (CR). By design, per‐hectare plant populations were greatest in 19‐ and least in 76‐cm row spacings. Plots were hand harvested. Reductions in row spacing decreased plant height, main stem nodes plant−1, and subset (first position bolls at nodes 6–10) individual boll weight. Greater N increased plant height, main stem nodes plant−1, and both whole‐plant and subset individual boll weight. Lint percentage was increased by reduction in row spacing and not affected by N. Treatment effects on fiber quality were limited. Lint yield did not differ among row spacings. Significant increases in lint yield occurred with each increase in N, suggesting that the optimal N rate was not surpassed. Nitrogen by row spacing interaction on lint yield was not significant, implying a similar response of each row spacing to N over the fertilizer rates tested. The N fertilizer requirements of UNR do not appear to be lower than those of CR cotton.

Efficacy of KIH-485 on Texas Panicum (Panicum texanum) and Selected Broadleaf Weeds in Corn1

KIH-485 is an experimental herbicide being evaluated for preemergence weed control in corn. Field experiments were conducted in Burleson County, Texas, in 2003 and 2004 to compare weed control, corn tolerance, and corn yield with various rates of KIH-485 or S-metolachlor. Each herbicide was applied in single preemergence applications at four rates, or in combination with atrazine. KIH-485 at 500 g ai/ha provided better Texas panicum control than S-metolachlor by 9 WAT. KIH-485 or S-metolachlor treatments controlled Palmer amaranth at least 91% at all evaluation dates. In 2003, no other treatment controlled velvetleaf better than 500 g/ha KIH-485. The following year, all KIH-485 rates above 125 g/ha controlled velvetleaf better than any rate of S-metolachlor alone. Moreover, KIH-485 controlled all weed species as good as or better than S-metolachlor plus atrazine, regardless of KIH-485 rate. There was no significant corn injury observed, and grain yield reflected the effects of weed control. Nomenclature: ...

An Economic Comparison between Conventional and No‐Tillage Farming Systems in Burleson County, Texas

Tillage systems that reduce the number of cultivation steps can, according to soil scientists, save soil moisture, fuel, labor, and machinery costs, as well as reduce wind and water erosion. However, many producers in South Texas are reluctant to adopt these practices. The objective of this study was to compare the economics of conventional tillage (CT) and no‐tillage (NT) systems on three commercial crops produced in South Texas: grain sorghum [Sorghum bicolor (L.) Moench], wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.]. When considering the economics of both tillage systems, three areas affecting profit were addressed: changes in cost per hectare, changes in yield per hectare, and the impact on net income risk. Empirical distributions of net income for different tillage systems under risk were estimated using a Monte Carlo simulation model of net income per hectare. Certainty equivalents were used to rank the tillage systems because they can be used to rank risky alternatives for risk‐averse decision makers. The risk premium for risk‐averse decision makers who prefer NT over CT ranges between $12.60 and $34.25 per hectare for all five crop rotations. Risk‐neutral decision makers would prefer continuous sorghum and sorghum–wheat–soybean rotation over all other rotations under CT and NT, respectively. However, risk‐averse decision makers would prefer continuous sorghum over all other rotations either under CT or NT. The results suggest that under risk‐neutral rankings, NT would be preferred over CT in three out of the five crop rotations tested. However, assuming a risk‐averse decision maker, NT would be preferred over CT in all five crop rotations.

An Economic Comparison between Conventional and No-Tillage Farming Systems in Burleson County, Texas

Tillage systems that reduce the number of cultivation steps can, according to soil scientists, save soil moisture, fuel, labor, and machinery costs, as well as reduce wind and water erosion. However, many producers in South Texas are reluctant to adopt these practices. The objective of this study was to compare the economics of conventional tillage (CT) and no-tillage (NT) systems on three commercial crops produced in South Texas: grain sorghum [Sorghum bicolor (L.) Moench], wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.]. When considering the economics of both tillage systems, three areas affecting profit were addressed: changes in cost per hectare, changes in yield per hectare, and the impact on net income risk. Empirical distributions of net income for different tillage systems under risk were estimated using a Monte Carlo simulation model of net income per hectare. Certainty equivalents were used to rank the tillage systems because they can be used to rank risky alternatives for risk-averse decision makers. The risk premium for risk-averse decision makers who prefer NT over CT ranges between $12.60 and $34.25 per hectare for all five crop rotations. Risk-neutral decision makers would prefer continuous sorghum and sorghum–wheat–soybean rotation over all other rotations under CT and NT, respectively. However, risk-averse decision makers would prefer continuous sorghum over all other rotations either under CT or NT. The results suggest that under risk-neutral rankings, NT would be preferred over CT in three out of the five crop rotations tested. However, assuming a risk-averse decision maker, NT would be preferred over CT in all five crop rotations.

Johnsongrass (Sorghum halepense) Control Systems for Field Corn (Zea mays) Utilizing Crop Rotation and Herbicides

Johnsongrass control systems that included commercially available corn herbicides applied to crop sequences of continuous corn or corn–cotton–corn rotation were evaluated over a 3-yr period at the Texas Agricultural Experiment Station in Burleson County. Herbicide treatments evaluated were EPTC + R-25788 applied preplant incorporated (PPI); metolachlor applied preemergence (PRE); nicosulfuron applied postemergence (POST); and the combination of metolachlor PRE and glyphosate POST applied after corn harvest. Weed control practices applied to plots planted to cotton in the second growing season provided excellent johnsongrass control (≈ 95%). Visual control ratings indicated that nicosulfuron provided the best johnsongrass control (&gt; 80%) among the herbicides evaluated all three years. Metolachlor and glyphosate combinations provided acceptable johnsongrass control the third year of the experiment in both cropping sequences. Corn grain yield and johnsongrass control were best in cotton-rotated plots. The highest returns observed in continuous corn were from either nicosulfuron or the combination of metolachlor and glyphosate. Net returns for all control systems in corn–cotton–corn rotated plots were greater than the weedy check and were equivalent to the lead systems in continuous corn.

MODELING MACROPORE TRANSPORT OF AGRICULTURAL CHEMICALS ON A RIVER FLOODPLAIN: ATRAZINE TRANSPORT SIMULATION

The United States Geological Survey (USGS) model Variably Saturated Two Dimensional Transport (VS2DT)was used to simulate macropore transport of atrazine through a highly structured clay soil to a sand and gravel floodplainaquifer at a field research site in Burleson County, Texas. A simulation of preferential flow through the surface clay wassuccessfully coupled with a simulation of groundwater flow in a floodplain aquifer. Simulated groundwater flow and atrazinetransport compared favorably with field measured values. The water levels in the floodplain aquifer were primarilyinfluenced by fluctuations in river stage. Simulated groundwater and surface water flows into and out of the aquifer werecalculated. Groundwater discharge from the aquifer to the river averaged 0.023 m3/s/km during low river stages. Surfacewater recharge to the aquifer averaged 0.022 m3/s/km during high river stages. Simulated atrazine transport through theclay soil domain resulted in atrazine losses (percent of total applied) of 7% in 1994 and 15 % in 1995. A pumping test at theresearch site and more rainfall in 1995 than in 1994 resulted in simulated atrazine transport to the bottom of the sand andgravel aquifer (19 m). Atrazine was not transported to the river in groundwater flow during model simulations. Simulatedatrazine concentrations were validated using measured concentrations throughout the study period.

Flight Potential of Feral Helicoverpa zea (Lepidoptera: Noctuidae) Males Measured with a 32-Channel, Computer-Monitored, Flight-Mill System

Single-night flight performances of 256 fetal corn earworm males, Helicoverpa zea (Boddie), were measured with a 32-channel, computer-monitored flight-mill system to evaluate their potential and propensity for engaging in long-distance, migratory-type flight. Test moths were males of mixed age that were selected randomly from daily catches in pheromone-baited traps located adjacent to fields of silking corn, Zea mays (L.), in Burleson County near College Station, TX, during the period of 16 and 30 June 1992. Flight was observed in 96% (n = 256) of the moths tested ; however, because of mortality and other factors, only 52% (134) remained capable of flight throughout the 9.75-h simulated scotophase period. The 134 moths averaged flying a total distance of 32.53 km in 17 separate flights during 5.61 h of total flight time which included an average maximum-duration sustained single flight of 18.8 km of 2.98 h duration. Thus, the fetal H. zea males demonstrated a high potential for long-distance flight. Other observed characteristics of moth behavior and flight performance are discussed, and the flight-mill system is described.

Seasonal Radar and Meteorological Observations Associated with Nocturnal Insect Flight at Altitudes to 900 Meters

Nocturnal aerial insect flight activities between 30 and 900 m above ground level were monitored with 3-cm scanning radar during the spring, summer, and fall seasons of 1988 and 1989 in the Brazos River Valley of Burleson County near College Station, TX. Surface meteorological parameters were measured continuously with weather station instrumentation, and radiosondes carried aloft by weather balloons were used to measure upper-air temperatures and wind conditions. Aerial volume density patterns and flight behaviors observed with radar varied nightly because of the many biological and meteorological variables involved, but certain seasonal characteristics of insect flight behavior became apparent during the course of the research. Nightly local dispersal flights at dusk were the norm, especially during the summer. Large numbers of insects were typically airborne for 1 to 2 h beginning about one-half hour after sunset with some of them reaching altitudes of 800 m or more where wind speeds were typically greater than 30 km/h. Several apparent long-range migration-type insect movement events were observed in which insects were concentrated in layers in high-speed, low-level wind jets that were apparently associated with nocturnal upper-air temperature inversions. Migration-type movement of insects tended to be south to north in the spring and early summer and north to south in the fall.

Occurrence of the spatangid echinoidMaretia arguta(Clark) in the Middle Eocene of Texas

Echinoid fragments were reported by Zachos (1990) from a Weches Formation (Clairborne) outcrop on Hooker Creek in Burleson County, Texas. Enough fragments have been found at the latter locality to piece together a composite identifiable as a species of the spatangid genusMaretia, most likelyM. arguta.This species has not previously been reported outside of Clarke County, Mississippi. A search of the stratigraphic collections of the Texas Memorial Museum in Austin, Texas, has uncovered several previously unidentified specimens ofM. argutafrom two Weches localities, at Kickapoo Shoals on the Trinity River in Houston County and at Nacogdoches in Nacogdoches County. In addition, spatangoid fragments, some of which are attributable toM. arguta, are common in collections from the Weches and Cook Mountain Formations.

Planting Date and Moisture Effects on Yield, Quality, and Alkaline‐Processing Characteristics of Food‐Grade Maize

Grain quality specifications for maize (Zea mays L.) have been established for several processing industries. Our objective was to investigate the effects of planting date and moisture level on grain yield, physical grain quality, and alkaline‐processing characteristics of food‐grade maize. Field experiments were conducted in 1998 and 1989 at the Texas A&amp;M University Farm, Burleson County, Texas. Seven food‐grade maize hybrids and one nonprocessing hybrid were grown with two planting dates (normal and delayed) and two moisture levels (irrigated and dryland). Delayed planting, averaged across years, decreased grain yield 15.2%, kernel weight 6.8%, kernel density 1.8%, and kernel hardness 4.4%. In 1988, the dryland treatment decreased grain yield 30.0%, kernel weight 15.2%, and kernel density 1.8%, and increased kernel protein 5%, but had no effect in 1989. Kernel hardness decreased 2.8% in 1988 with dryland treatment, but increased 4.5% in 1989. Hybrid effects varied with year for kernel weight, density, hardness, and protein. The nonprocessing hybrid (B73 × Mo17) produced high grain yield (7911 kg ha−1) and average kernel protein (109 g kg−1 but relatively low kernel weight (270 mg), density (1.06 g cm−3), and hardness (45.4%). Of the food‐quality hybrids, none consistently outperformed the others in all categories. Alkaline‐processing characteristics of the grain were affected by agronomic inputs. In general, nixtamal (i.e., cooked grain after alkaline processing) moisture increased due to delayed plantings and reduced soil water availability. Dry‐matter loss exhibited no discernible trends. Pericarp removal (qualitatively scored) was greatly affected by hybrid; RX404 consistently outperformed all other hybrids.