. Table 5. Sweet corn ear diameter as affected by gall location and gall size interaction in Ustilago maydis -infected plants in 2002 and 2003 at Hermiston, OR. Ear length was similar in 2002 and 2003 and increased slightly from the early to the late
George H. Clough, Sarah Blatchford and Philip B. Hamm
A.D. Bratsch and H.J. Mack
Field experiments were conducted in 1986 through 1988 to evaluate the effects of rates and timing of ethephon application on growth, yield, and lodging of `Jubilee' sweet corn (Zea mays L.). As a comparison, hand-topping was performed 10 days after early silking to simulate the commercial practice of mechanical topping to reduce lodging. Ethephon reduced plant height by 12% to 26%, with timing of application determining location of internode length reductions. There was greater reduction of ear height by ethephon applied at tassel elongation (TE) than at 1 and 2 weeks later. Effects of ethephon on husked yield varied from an 8% increase in yield to an 18% decrease, depending on rate, timing, and season. Topping reduced yield in one of the four experiments. Ear length was reduced by ethephon at 0.28 kg·ha-1 in two of the four experiments. A helicopter fly-over resulted in 66% of topped plants lodging, compared to 87% of untreated plants. Lodging of plants that received an ethephon application of 0.28 kg·ha-1 at TE averaged 51% for Expts. 2, 3, and 4. The amount of lodging tended to be least in those ethephon treatments with the largest reduction `in plant or ear height. Chemical names used: 2-chloroethyl phosphonic acid (ethephon).
Anusuya Rangarajan, Betsy Ingall, Michael Orfanedes and David Wolfe
Early-planted fresh market sweet corn (Zea mays) is prone to nonuniform ear length and quality due to uneven germination in cool soils. Growers compensate by reducing in-row spacing at seeding, to increase final plant stand. This risk management strategy was suspected to be reducing quality of early-planted sweet corn, based upon buyer feedback. Four experiments were conducted in upstate New York, to examine the effects of in-row spacing and cultivar on early-planted sweet corn ear yield, length and uniformity. Cultivars examined included `Temptation' (4 years), `Sweet Symphony' (3 years) and `Seneca Spring' (2 years). In-row spacings tested ranged from 6 to 9 inches (15.2 to 22.9 cm), using a 30-inch (76.2-cm) between-row spacing. In-row spacing and cultivar influenced marketable yield, husked ear weight and length of early-planted corn, but the extent varied by year. Despite improvements in individual ear weight and length at wider in-row spacing, marketable yield was usually higher at more narrow spacings. Increases in ear weight at wider spacings were usually associated with increases in weight of the outer, green husk. Average ear length of a cultivar varied between 0.2 and 0.6 inches (0.5 to 1.5 cm) in response to spacing. If ears longer than 7 inches (17.8 cm) were desired, 40% to 60% of ears satisfied this criteria if harvested from plants grown at 8-inch (20.3-cm) in-row spacing or a plant population of 26,000 plants/acre (64,200 plants/ha). Ear weight and length of `Seneca Spring' was not as affected by the in-row spacing treatments compared to the other two cultivars, perhaps due to the small size of this cultivar. Selection of smaller sized sweet corn cultivars for planting at high plant populations (6-inch in-row spacing) may reduce the variation in ear weight under challenging early season conditions. For cultivars with similar growth characteristics and maturities of `Temptation' and `Sweet Symphony,' a minimum in-row spacing of 8 to 9 inches or a plant population of 23,200 to 26,000 plants/acre (57,300 to 64,200 plants/ha) was recommended to minimize variation in ear yield and quality from first bareground plantings in the northeastern United States.
Matthew D. Kleinhenz
A total of 21 and 28 standard and experimental varieties of yellow and white se- and sh2-type sweet corn (Zea mays) were planted in 1999 and 2000 in Fremont and Wooster, Ohio, which are separated by 193.1 km (120 miles) and contain different soil types. Data are reported here for a subset of these varieties (eight yellow, two white) showing a consistently high level of use in Ohio and planted in both years. Endosperm types were planted in distinct, parallel experiments separated by a minimum of 79.9 m (262 ft) at each site. A randomized complete block design with four replications per variety (V) per location (L) was used, with measures of 13 production- and market-based variables taken from emergence to 48 hours after harvest. Soluble solids 48 hours after harvest were greater at Wooster than Fremont in the sh2 study. Variety had a significant, independent effect on mean plant and ear height in the se and sh2 study, respectively, although further analysis of year × variety (Y × V) and location × variety (L × V) interactions suggested that V affected additional traits. On average, `Tuxedo' (se) and `HMX6383S' (sh2) had superior com-binations of grower- and consumer-oriented traits. However, varieties with the highest levels of percent emergence and marketable yield tended to have lower levels of soluble solids, regardless of endosperm type. Y × V interactions were primarily due to changes in the magnitude of values for individual varieties in each year, not from changes in their relative ranking. The Y × L × V interaction was significant (P ≤ 0.05) for marketable yield, plant and ear height, and the ratio of ear length to diameter in the se study, but zero variables in the sh2 study. Coefficients of determination (R 2) for selected plant and ear traits were unaffected by location. Overall, R2 values ranged from 0.04 (number of rows of kernels × ear diameter, sh2 study) to 0.83 (shank length × total ear length, sh2 study). These data reinforce that genetics strongly affect key traits in sweet corn and identify two potential top performers. The data also suggest that independent L or L × V effects may be minor relative to V effects, even when locations are separated by moderate distances and contain different soil types. Therefore, including more varieties but fewer sites may be warranted in future variety trials. The data also suggest that 1) ratings of variety performance should be based on objective measures of grower- and market-oriented traits and 2) shank length × total ear length and ear height × plant height relationships may be used to improve the efficiency of future evaluations.
Thomas M. Butzler, Elsa S. Sánchez, Steven M. Bogash, Timothy E. Elkner, William J. Lamont Jr., Robert Pollock and Lee J. Stivers
1102’ had a smaller ear diameter in 2013 at the central site. Table 4. Ear size measured as diameter and length for 25 cultivars of synergistic sweet corn grown in southwestern, central, and southeastern Pennsylvania in 2012 and 2013. Ear length of most
Martin M. Williams II
ear mass) are important in processing hybrids ( Tracy, 1993 ). How plant density affects the reproductive sink of sweet corn is poorly known. In general, ear mass, filled ear length, and recovery decrease at higher plant densities ( Rogers and Lomman
Virginia M. Moore and William F. Tracy
for longer husks indirectly confers improved resistance to the corn earworm, and finally to compare husk extension, ear length, earworm infestation rate, and extent of damage of each cycle of selection to commercial cultivars used on organic farms in
Luther Waters Jr., Rhoda L. Burrows, Mark A. Bennett and John Schoenecker
A series of experiments exploring the effect of seed moisture and transplant management techniques was conducted with sh2 and su sweet corn (Zea mays L.). The use of seed and transplants in a progression of developmental stages from dry seed to moistened seed to 14-day-old transplants showed that moistened seed had no impact on plant `growth and development. Use of transplants generally had little impact beyond decreasing percent survival and plant height. Increasing the age of transplants reduced the time to maturity and harvest. Increasing the size of the transplant container (paper pot) decreased the time to harvest for younger seedings, but had no other effects. Premoistened seed were successfully held at 10C for up to 72 hours without damage following moisturization. Delays in irrigation of up to 2 days after planting moistened seed had no detrimental effects on sweet corn emergence and growth.
Hamid Reza Rajablarijani, Bahram Mirshekari, Majid AghaAlikhani, Varahram Rashidi and Farhad Farahvash
plots relative to unmulched weeded treatments. In contrast, plastic mulch advanced maturity by 3 d ( Table 2 ). Table 2. Effects of sowing date and mulch on kernel number per ear, length of ear, unfilled ear tips, and days from sowing to harvest and 50
Anusuya Rangarajan, Betsy A. Ingall and Michael S. Orfanedes
Early fresh-market sweet corn expressed concern is prone to variability in ear length and quality due to uneven germination rates in cooler soils, smaller plant size of early corn, and single ear per stalk trait of early varieties. In an informal survey of current practices, growers reported using in-row spacings between 0.5 and 0.25 m (0.76 m between rows) for their first bare-ground corn, representing a range of plant populations from 86,000 to 43,000 plants/ha. However, no information had been gathered on the impacts of these various in-row spacings on early corn ear length and overall quality and how different sweet corn types (se, sh2, sweet breeds) might respond to these spacings under cool conditions of early spring. Four trials were conducted over the last 2 years, in upstate New York, examining three sweet corn types, five plant populations, and two nitrogen sidedress rates for effect ear length, quality, and uniformity. In general, results thus far indicate that all three parameters can influence ear quality and variability. Among treatments, ear length varied by up to 1 cm. The variety `Sweet Symphony' was less affected by high populations than `Temptation'. In 1998, no difference in ear length due to spacing was found. It is suspected that the warm spring in 1998, coupled with adequate moisture, reduced plant stress during early growth. Higher nitrogen sidedress rates reduced variability of early season corn, at all populations. In 1999, plant population was found to be the most important factor affecting ear physical characteristics.