Marketable Ears Research Articles

In-furrow Starter Fertilization Enhances Growth and Maturity in Early Sweet Corn

Field studies were conducted in 1994 and 1995 to evaluate the effects of in-furrow-placed (i.e., applied directly in the seed channel) starter fertilizer on the emergence, maturity, and yield response of early sweet corn. In both years, three starter fertilizer treatments were applied: APP, with N and P at 13 and 19 kg·ha-1, respectively (13N—19P kg·ha-1), either banded (5 cm below and 5 cm to the side of the seed) or placed in-furrow, and a control (no starter fertilizer). Additionally, in 1995, the rate of APP was increased to supply 26N—38P kg·ha-1 in combination with either band (5 × 5 cm) or in-furrow placement. Seedling emergence was delayed whenever starter fertilizer was applied with the seed; however, significant reductions (≈21%) in plant stand occurred only at the high rate of in-furrow placement. In both years, all starter treatments had a positive effect on seedling dry-matter production, and hastened silking. In-furrow application of 13N—19P kg·ha-1 increased marketable ear yields 34% in 1995, but had no effect in 1994. Lack of yield response to the high rate of in-furrow fertilizer in 1995 was primarily a function of reduced stand, as ear number and ear mass per plant, and average ear size were similar to those in the other starter treatments. Based on these results, in-furrow APP at 13N—19P kg·ha-1 appears to be an effective starter fertilization regime for early sweet corn, comparable in effect to banded 26N—38P kg·ha-1. However, high rates of in-furrow APP may reduce stands. Although significant yield response to in-furrow starter fertilizer may not always be realized, the increased early seedling growth may itself be a benefit, since fast-growing seedlings are more likely to be tolerant of adverse environmental conditions than are less vigorous plants. Chemical name used: ammonium polyphosphate (APP).

Potential application of the entomopathogenic fungus, Nomuraea rileyi, for control of the corn earworm, Helicoverpa armigera

AbstractThe entomopathogenic fungus, Nomuraea rileyi, caused 90.5–100% mortality in fourth‐instar larvae of the corn earworm, Helicoverpa armigera, when applied at 107 conidia/ml to corn silks, and leaves of soybean, tomato and chrysanthemum. The LT50 was 5.9–6.7 days. The fifth‐instar larvae showed a mortality of 94.6% on soil with 20% water content, and 41.7% on 10% water content when the soil surface was sprayed with 108 conidia/ml suspension. Five fungicides, eight insecticides and nine herbicides, which are commonly used in corn fields, were evaluated for inhibition to conidial germination by a paper disk test. Among them, only two fungicides, viz., maneb and propineb, were highly inhibitory, while insecticides and herbicides examined were not inhibitory to the fungus. Field applications of N. rileyi conidial suspension to neonate larvae were found to be as effective as 40.46% carbofuran (EC) at 800‐fold dilution in controlling corn earworm based on marketable ears. It is thus suggested that N. rileyi has potential to be a microbial control agent for this insect.

Disease Severity and Yield of Sweet Corn Hybrids with Resistance to Northern Leaf Blight.

Reactions of supersweet (sh2) sweet corn to northern leaf blight (NLB) and associated yields were evaluated in Belle Glade, Florida and Urbana, Illinois in yield-loss trials, hybrid evaluations, and evaluations of breeding materials. Hybrids differed significantly for NLB in all trials. Severity of NLB ranged from 0 to 66% on 35 sh2 hybrids in yield-loss trials, and from 0 to 60% on 80 sh2 hybrids in hybrid evaluations. NLB ratings ranged from 1 to 9 (approximately 0 to 80% severity) on 375 hybrids and 186 inbred lines in evaluations of breeding materials. Various methods of rating NLB and ratings from multiple dates were highly correlated, with correlation coefficients ranging from 0.76 to 0.98. Yield, measured as weight of ears and number of marketable ears from inoculated plots as a percentage of that from control plots, decreased as disease severity increased. Linear or quadratic regression models explained 31 to 70% of the variation in percent yield as a function of disease severity at harvest. The effects of NLB on yield were limited by NLB-resistance in several hybrids, including CCO 3268, Chieftain, Crisp N Sweet 710A, Day Star, Envy, Forever, GSS 1526, Jupiter, Midship, Prime Plus, Sch 5005, and SummerSweet 7630. Although high levels of partial resistance to NLB were prevalent among 375 new experimental sh2 hybrids and 186 sh2 inbred lines evaluated in 1995, use of the gene HtN may increase in the near future as breeders are incorporating this resistance into new inbreds and hybrids. Breeders and plant pathologists would be wise to continue improving partial resistance to NLB without using the gene HtN in genotypes with adequate levels of partial resistance, because the widespread use of the gene HtN will select for virulent races of Exserohilum turcicum which occur in Florida, or for races with new combinations of virulence.

Bacterial Leaf Blight on shrunken-2 Sweet Corn.

Severity of bacterial leaf blight (BLB, caused by Acidovorax avenae subsp. avenae) on shrunken-2 (sh2) sweet corn hybrids grown in BLB-conducive environments and sporadic outbreaks of BLB in recent years warranted evaluations of the potential for this disease to cause economic losses. BLB symptoms on 122 sh2 hybrids, 30 sh2 inbred lines, and 29 crosses of the inbreds and the effects of BLB on yield (ear weight and marketable ears) were evaluated in 1994 and 1996. BLB severity ratings for 122 hybrids averaged 3.3 and 3.7 (on a scale of 1 to 9) in 1994 and 1996, respectively. Hybrid means ranged from 1.8 to 5.5 in 1994 and from 1.9 to 5.7 in 1996, with Bayesian LSD values of 1.20 and 1.22, respectively. There were no differences in BLB ratings among hybrids with yellow, white, or bicolored kernels. Severity of symptoms on 30 sh2 inbreds ranged from 1.5 to 5.7, whereas the reactions of 29 crosses of the inbreds ranged from 1.9 to 5. The slope coefficient of the regression of crosses on mid-parent values was not different from 1. Thus, mid-parent values gave a good indication of severity of BLB symptoms on crosses, with the exception of a few crosses that tended to be more severely infected than expected based on mid-parent values. Ear weights and number of marketable ears differed among hybrids in the 1994 trial, but there was no significant effect of BLB treatments on either of these measures of yield. In 1996, ear weights in inoculated plots were 10 and 15% lower than those from noninoculated plots for 2 of 12 hybrids. Despite moderately severe foliar symptoms, BLB did not affect yield substantially in these trials even among hybrids with the most susceptible reactions.

Field Application of Bacillus thuringiensis and Anagrapha falcifera Multiple Nucleopolyhedrovirus Against the Corn Earworm, (Lepidoptera: Noctuidae)

Field evaluations were made of relative efficacy of 2 subspecies of Bacillus Thuringiensis Berliner and Anagrapha falcifera multiple nucleopolyhedrovirus (AfMNPV) to control Helicoverpa zea (Boddie) on corn ears. Also, the compatibility of a starch-based additive—a 1:1 mixture of starch (Mirasperse) and sucrose—was determined when added to the entomopathogens. Applications of the 3 pathogens significantly decreased the percentage of ears damaged by H. zea and increased the percentage of ears with no damage and marketable ears. AfMNPV was as good as or better than the B. thuringiensis products in protecting the corn ear. The starch additive was determined to be compatible with the pathogens but did not enhance their activity.

Management Practices for Carnival-season Production of Immature Field Corn in Trinidad and Tobago

Immature field corn (Zea mays L.) grown for pre-lenten carnival festivities in Trinidad and Tobago can be a profitable cash crop. Hybrid and local unimproved open-pollinated corn were grown with two levels of weed control and fertilizer application late in the rainy season at two locations each on Trinidad and on Tobago. The Trinidad locations were situated on more productive agricultural land than those on Tobago. The hybrid `Pioneer 3098' yielded more edible corn than the local variety at all locations and at all treatment levels. Manual weed removal at the four- to five-leaf stage was sufficient to allow corn to out-compete the weed canopy, and an additional field operation would not be justifiable. On Tobago, the application of fertilizer just before tasselling, in addition to an earlier application of urea, increased the number and yield of edible ears. Few boiling-quality, marketable ears were produced on Tobago. On Trinidad, the additional fertilizer did not alter yield. For commercial carnival-season production of immature field corn on productive soils in Trinidad, the purchase of imported hybrid seed is economically justifiable, but high inputs into weed control and fertility management may not be needed.

Yield and Quality Attributes of Rainfed Green Immature Corn in Trinidad

Three local varietal types of corn (Zea mays L.)—an improved landrace `ICTA Farm Corn' derived from the Tuson population, the open-pollinated `Across 7728', and the hybrid `Pioneer 3098'—were grown at three cash-crop farms in Trinidad, and evaluated as green corn for agronomic, quality, and chemical traits. `Pioneer 3098' and `ICTA Farm Corn' had similar numbers of marketable ears and marketable yield per hectare, and both were superior to `Across 7728'. Sensory evaluations revealed that the three varieties did not differ in overall quality when boiled with Creole seasoning. When ears were not seasoned, the hybrid variety was preferred over the two open-pollinated varieties. Two-dimensional partitioning indicated that ear appearance and kernel color were the major contributors to total variation in overall quality. The importance of quality characters of green corn to local farming system priorities affects extension recommendations and breeding objectives in Trinidad.

Diallel study of open-pollinated maize varieties in Trinidad

In Trinidad, maize (Zea mays L.) is primarily harvested in the immature stage as green ears for human consumption. The purchase of popular imported hybrid seed has become a substantial component of the economic inputs of maize production. The objectives of this study were to investigate combining abilities and heterotic patterns among available open-pollinated varieties and to assess correlations among five important traits: time to silking, plant height, grain yield, ear size, and marketable ears per hectare. General combining ability was significant for all traits. Specific combining ability was significant for all traits except ear size. Three intervarietal crosses showed moderate levels of heterosis (10–27%), and several yielded similarly to the control hybrids, Pioneer X304 and Pioneer 3078. The cross Acid Soil Tolerant 1991 SA-3 X ICTA Farm Corn was selected as the most suitable base population for mass selection. Phenotypic and genotypic correlations among the five traits studied were all positive and significant. Populations which flowered early were shorter and yielded less than the late flowering and taller populations and population crosses included in this study.

Pre-sidedress Soil Nitrate Test for Sweet Corn

Research was conducted with sweet corn (Zea mays L.) to evaluate the presidedress soil NO3 test (PSNT) originally developed for use on field corn on a wide range of New Jersey soils. Soil NO3-N concentrations reflected differences in N availability due to manure or preplant N application. The relationship between soil NO3-N concentration and relative yield of marketable ears was examined using Cate–Nelson analysis to define the PSNT critical level. Soil NO3-N concentrations >25 mg·kg–1 were associated with relative yields at ≥92%. The success rate for the PSNT critical level was 85% for predicting whether sidedress N was needed. Including NH4-N in the soil analysis did not improve the accuracy of the soil test for predicting whether sidedress N was needed. Although the PSNT is quite accurate in identifying N-sufficient sites, it appears to offer only limited guidance in making N-fertilizer rate predictions. The PSNT is most useful on manured soils, which frequently have sufficient N. The test likely will help decrease the practice of applying “insurance” fertilizer N and the ensuing potential for NO3 pollution of the environment.

On-Farm Efficacy of Aerially Applied Bacillus thuringiensis for European Corn Borer (Lepidoptera: Pyralidae) and Corn Earworm (Lepidoptera: Noctuidae) Control in Sweet Corn

Aerial applications of Bacillus thuringiensis subsp. kurstaki and tank-mixes with synthetic insecticides were evaluated for control of Ostrinia nubilalis (Hubner) and Helicoverpa erpa zea (Boddie) in Minnesota sweet com during 1990-1992. In addition to natural infestations, sweet com was manually infested with first-instar O. nubilalis to investigate optimum timing of applications relative to larval hatch. Efficacy of B. thuringiensis was significantly enhanced when applied 2 d before larval hatch, compared with 2 d after hatch. Treatments with low-rate permethrin + B. thuringiensis or full-rate permethrin followed by B. thuringiensis provided control of O. nubilalis equal to full rates of permethrin or micro-encapsulated methyl parathion. Of the B. thuringiensis treatments, only the tank-mix of low-rate permethrin + Dipel ES significantly reduced H. zea larval infestations and yielded more marketable ears than the untreated check. Based on active ingredient per hectare, low-rate permethrin + B. thuringiensis reduced synthetic insecticide use 66%, compared with full-rate permethrin, or 92% compared with full-rate methyl parathion. Using a four-application program, permethrin followed by three B. thuringiensis applications reduced synthetic insecticide use 75'% compared With full-rate permethrin, or 94% compared with full-rate methyl parathion. Disadvantages of the use of B. thuringiensis for late-season insect management in sweet corn include application timing, incidence of H. zea, and potential for increased risk of larval contaminants in marketable product.

Effect of Nicosulfuron Applied Postemergence and Post-Directed on Sweet Corn (Zea mays) Tolerance

In 1991 and 1993, tolerance of ‘Zenith’ and ‘Merit’ sweet corn to 35 g ai/ha nicosulfuron post-directed (PDIR) 0, 5, 10, and 15 cm up the corn stalk or applied POST was determined. In 1991, nicosulfuron applied POST to Zenith caused approximately 30% visible injury, 30% height reduction, and 50% reduction of U.S. No. 1 marketable ear weight. In 1991 no visible injury was observed in the PDIR treatments. Zenith was not injured by any treatment in 1993. Both years, Merit was killed by nicosulfuron applied POST. In 1991 and 1993, nicosulfuron PDIR 0 and 5 cm up the corn stalk of Merit caused approximately 5% and 65% visible injury, respectively, and resulted in yield loss. PDIR application increased nicosulfuron tolerance of moderately tolerant Zenith but did not improve that of least tolerant Merit.

287 IMPROVED PERFORMANCE OF SHRUNKEN-2 SWEET CORN USING TRICHODERM HARZIANUM AS A BIOPROTECTANT

A strain of the biocontrol fungus Trichoderma harzianum was tested for effectiveness in improving the performance of sh2 sweet corn using a variety of delivery methods. In greenhouse trials, Trichoderma seed treatment reduced the proportion of weak plants (unlikely to make a marketable ear) from 40% to 10%. This is evidence that the characteristically uneven stand establishment of supersweet corn should be overcome by using Trichoderma. In field trials, Trichoderma and Gliocladium (a related fungus) were inoculated as a seed treatment without fungicide in spring-tilled plots. Yields of uninoculated controls were 2.2, Gliocladium-treated were 2.6, and Trichoderma -treated were 3.6 T/ac. Delivering the same lines of fungus in the fall to a rye cover crop resulted in high populations the following spring. The cover crop was killed and fungicide-treated seed of `Zenith' sweet corn was planted without tillage. Yield with Trichoderma was 4.0, with Gliocladium was 3.7, and uninoculated was 2.4 T/at. The uninoculated, conventionally-tilled plots also yielded 4 T/at. Thus the beneficial fungi overcame the inhibition caused by no-till. Trichoderma was delivered effectively both as a seed treatment and on a winter cover crop to improve stand uniformity and overall yield.

HAIL DAMAGE ON THREE VEGETABLE CROPS

U.S. crop loss from hail damage amounted to $246,443,391 in 1991. Premiums paid for hail insurance was $403,742,507. Despite the magnitude of this industry, the effects of varying levels of hail injury at different stages of plant growth is largely unknown for many vegetable crops. To further evaluate the effects of hail on strawberries, watermelons, and sweet corn, several studies were established in 1991 and 1992. Simulated hail applications were made at different rates and stages of crop growth. Total yields and marketable yields of strawberries were reduced by hail applications. All hail treatments reduced the number of marketable watermelons, except for the vegetative size light hail treatment in 1991. In 1992, the early treatments caused the most total yield reduction. All hail treatments reduced the percentage of marketable ears of sweet corn, except for the light application in the 13th leaf stage (early vegetative) in 1991. In 1992, additional treatments consisting of clipping all leaves were conducted. Clipping leaves at the early silking stage reduced marketable ears, indicating the loss of foliage adversely affected the growth of the ear. Clipping leaves just prior to harvest reduced the yield of Jubilee, but not Silver Queen.

Conventional Selection versus Methods that Use Genotype × Environment Interaction in Sweet Corn Trials

The analysis of variance of a data set made up of 30 sweet corn (Zea mays L.) hybrids evaluated over 5 years for marketable ears (dozens per hectare) indicated a significant genotype (hybrid) × year (GY) interaction. Three selection methods were compared: 1) a conventional method based on mean yield alone (YA), 2) Kang's ranksum (KRS) method, and 3) Kang's modified rank-sum (KMR) method. The number of hybrids selected on the basis of YA, KRS, and KMR was 13. The KRS selected the lowest number of unstable hybrids (three) compared with the YA and KMR, which selected eight and six unstable hybrids, respectively. The mean yields of the selected hybrids were 3034 dozen/ha for YA, 2945 dozen/ha for KRS, and 3019 dozen/ha for KMR. The mean yield of KRS-selected hybrids and KMR-selected hybrids was <2.9% and 0.5%, respectively, than that of YA-based selections. This yield reduction was regarded as insignificant considering the farmer would be able to choose more consistently performing hybrids on the basis of KRS than on the basis of KMR or YA. Heterogeneity due to environmental index is the mean of all genotypes in the jth year and X is the overall mean) was significant and was removed from the GY interaction. The removal of heterogeneity revealed that hybrids 77-2269, 116-Kandy Korn-EH, Golden Queen, 141-Sundance, Merit, and Stowell Evergreen were unstable because of a linear effect of the environmental index, and that hybrids 76-2681 and 806F-Truckers showed stable performance due to a linear effect of the environmental index.

Sweet Corn Cultivars Respond Differentially to the Herbicide Nicosulfuron

Twelve sweet corn (Zea mays L. var. rugosa Bonaf.) cultivars were tested for response to nicosulfuron at rates of 0, 18, 36, and 72 g a.i./ha. Weight of marketable ears indicated that five cultivars were intolerant to the herbicide. Three of the cultivars that were intolerant contained the shrunken-2 endosperm mutant (sh) and two contained the sugary enhancer endosperm mutant (se). Cultivars that were most tolerant of nicosulfuron contained the sh, gene. Incorporation of terbufos insecticide before planting led to decreased marketable yield when nicosulfuron was applied at 36 g·ha in all cultivars tested. Chlorpyrifos insecticide incorporated before planting did not affect tolerance to nicosulfuron. Neither soil-applied insecticide affected yield when nicosulfuron was not applied. Chemical names used: 2-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfony]-N,N-dimethyl-3-pyridinecarboxamide (nicosulfuron); S-[[(1,1-dimethylethyl)thio]methyl] O,O-diethylphosphorodithioate (terbufos); O,O-diethyl O-(3,5,6-trichloro-2-pyridyl)phosphorothioate (chlorpyrifos).

Effects of Tillage and Mulch on Weed Biomass and Sweet Corn Yield

Sweet corn was grown with a living mulch of white clover, a dead mulch of rye, and without mulch, in both till and no-till conditions. Unplanted controls were also included in the experimental design. Corn yields were highest in clover treatments early in the experiment but lowest in later years. The declining yields in the clover living mulch were related to the strip application of glyphosate which allowed establishment of perennial and biennial weeds, notably dandelion and horseweed. These overwintering weeds apparently prevented effective control of summer annuals, especially redroot pigweed, common lambsquarters and large crabgrass, by atrazine and metolachlor. Presence of a rye mulch decreased weed biomass and had no detrimental effect on corn yield. In general, corn yield was not affected by tillage, although the number of marketable ears was reduced in the no-till treatments during the drought year of 1988. The much greater weed biomass in the unplanted control treatments showed the importance of crop competition for weed control in sweet corn cropping systems.

Effect of Steinernema feltiae on Spodoptera frugiperda and Heliothis zea (Lepidoptera: Noctuidae) in Corn

The entomogenous nematode Steinemema feltiae Filipjev was evaluated for control of fall armyworm, Spodoptera frugiperda (J. E. Smith), in vegetative field corn ( Zea mays [L.J] and for control of fall armyworm and corn earworm, Heliothis zea (Boddie), in sweet corn ears. In 3 yr of field tests in vegetative field corn, spraying the nematode resulted in up to 33-43% infection of fall S. frugiperda larvae and occasionally significant ( P <0.05) reductions in numbers of S. frugiperda infesting the corn. There was no significant increase in total yield of corn, although the dry weight of kernels per ear was significantly ( P < 0.05) greater in treatment plots than in control plots. Nematode dosage had a significant effect on percentages of infection, but neither spray volume nor the addition of a surfactant affected insect control by the nematode. In one experiment in sweet corn, spraying the nematode onto corn ears resulted in up to 71% infection and up to 53% reduction of a mixed population of H. zea and S. frugiperda , mostly the former. Nematode treatments did not increase sweet corn yield by weight. However, spraying the nematode at a pressure of 0.70 kg/em2 resulted in a significantly ( P < 0.05) higher percentage of US #1 grade marketable ears than in control plots, whereas spraying at 1.76 kg/em2 did not, regardless of the nematode dose.

Relationships between incidence and severity of Stewart's and Goss's bacterial wilts and yield of sweet corn hybrids

Relationships between severity and incidence of Stewart's and Goss's bacterial wilts (caused by Erwinia stewartii [Smith] Dye and Clavibacter michiganese subsp. nebraskense [Schuster] Davis et al.) and sweet corn ( Zea mays L.) yield were studied in factorial experiments with sweet corn hybrids, pathogens and incidence of initial infection as main factors. Relationships were similar for the two bacterial diseases but were affected differently by host resistance. Relationships between disease severity subjected to the square root transformation (severity 1 2 ) and incidence were linear in resistant and moderately resistant hybrids, cvs Miracle and Gold Cup, because the bacterial wilts did not become systemic in these genotypes following inoculation at the five- to seven-leaf stage. In the susceptible hybrid, cv. Jubilee, the relationship between severity 1 2 and incidence was curvilinear, with severity ranging from about 25% to 65% at 100% incidence, depending on the host growth stage at which plants were inoculated. Yield of the resistant and moderately resistant hybrids was not significantly affected by inoculation at the five- to seven-leaf stage. In the susceptible hybrid, ear weight and number of marketable ears were reduced approximately 1·5% for each 10% increase in incidence when plants were inoculated at the five- to seven-leaf stage in 1985 and approximately 5% and 3%, respectively, for each 10% increase in incidence when plants were inoculated at the three- to five-leaf stage in 1986. In 1988, relationships between yield and incidence were confounded by secondary spread; however, significant relationships between yield and disease severity at harvest were found in the susceptible hybrid inoculated at the three- to five- or the five- to seven-leaf stages. Estimating Stewart's and Goss's wilt severity and yield reductions based on incidence of initial infection could be of practical importance because it simplifies the method of disease assessment; however, estimates of severity and yield reductions must consider the level of host resistance, the growth stage at which plants were infected and the potential for secondary spread due to alloinfection.

Sweet Corn Response to Surface and Subsurface Trickle Phosphorus Fertigation

AbstractHigh‐frequency phosphorus fertigation may increase the time‐averaged P concentration in the soil solution above that expected from P solubility considerations. Where P is a yield‐limiting factor, frequent P fertigation may increase yield by stimulating P‐uptake by the roots. A field experiment was conducted on a loessial soil (Haploxeralf) high in NaHCO3‐extractable P (0.8 mmol kg−1 soil) to test the hypothesis that subsurface placement of emitters (SSR) is more effective in stimulating P uptake than surface placement (SR). Four concentrations of P in the water (Cp), 0.04,0.16,0.64, and 1.29 mol P m−3, were applied via surface or subsurface emitters to sweet corn [Zea mays (L.) Jubilee]. Marketable ear yield increased with Cp, yielding 22.9,24.3,24.9, and 28.9 t ha−1, respectively. Yield was higher for tricklers placed 30 cm below soil surface (25.2 t ha−1) than on the surface (23.5 t ha−1). Elevated Cp increased the soil solution P concentration, thereby increasing total P uptake and total dry matter production by the plants. Deep trickler placement significantly increased the fraction of total dry matter allocated to the ears, which resulted in higher marketable yield. Subsurface irrigation also reduced weed growth due to the dry top soil during the experiment.

Effects of the Sugary‐1 Locus on Plant and Ear Traits in Corn1

Attempts to use dent corn (Zea mays L.) to improve sugary‐1 (su) sweet corn have not been widely successful due to difficulty with the simultaneous recovery of traits being transferred and acceptable quality. The lack of success may be caused by linkage, pleiotropy of the su gene, inadequate recombination before initiating selection, or insufficient population size. The objective of this study was determine if the su allele affects 19 important sweet corn traits. Plants from starchy (Su) and sugary (su) So seed of a dent ✕ sugary composite were grown in four environments at 36 900, 57 400, and 73 800 plants ha−1, with ear measurements recorded at milk‐stage maturity. The Su and su S1 progenies were grown in two environments at 51 700 plants ha−1, with data taken on mature dried ears. Sugary So segregates demonstrated a greater tendency toward delayed maturity and lodging than Su segregates. Tip blanking was reduced in su So and S1 plants. Ear length was reduced in su So plants and Susu plants from Su‐‐S1 ears. Plant endosperm type had no effect on percent marketable ears or yield among So segregates, or on S1 ear diameter, taper, and curvature. The su gene effects provide some explanation for the difficulty encountered when using dent corn in sweet corn improvement, but were not so pronounced as to be insurmountable in a breeding program.