Relationship of Plant Phenology to Corn Yield Loss Resulting from Western Corn Rootworm (Coleoptera: Chrysomelidae) Larval Injury, Nitrogen Deficiency, and High Plant Density

1989 ◽  
Vol 82 (1) ◽  
pp. 226-231 ◽  
Author(s):  
Barbara P. Spike ◽  
Jon J. Tollefson
2020 ◽  
pp. 1202-1208
Author(s):  
Luan de Oliveira Nascimento ◽  
Josimar Batista Ferreira ◽  
Gleisson de Oliveira Nascimento ◽  
Vanderley Borges dos Santos ◽  
Clemeson Silva de Souza ◽  
...  

Increasing corn grain production without devastating new forest areas is a viable alternative to controlling deforestation. However, increasing plant density in the area may alter plant morphophysiological and productive traits. The objective of this study was to characterize relationships between physiological, morphological and yield traits of corn plants, as well as the cause, effect and relationship of the traits on grain yield. The experiment was carried out in randomized complete block design with four replications. The corn hybrids (2B655PW, AG7088PRO3 and P4285YHR) were grown with row spacing of 40 cm, 60 cm, 80 cm, 95 cm. The evaluated traits physiological were: net photosynthesis (PN), stomatal conductance (Gs), intercellular concentration of CO2 (Ci), leaf transpiration (E), water use efficiency (WUE) and carboxylation efficiency (CE). The morphological were: plant height (PH) and ear insertion height (EIH), stem diameter (SD), and leaf area (LA) and the productive traits were the total number of ear per hectare (NE), number of grains per ear (NGE), grain mass per ear (GME), 100 grain weight (100GW) and grain yield (GY). The characteristics of maize hybrids cultivated in environment with reduced spacing (40cm, 60cm, 80cm, 95cm) of the 2016/2017 crop were investigated through the multicollinearity path analysis. The physiological, morphological and productive traits are considered sources of variation of cause and effect of corn yield in reduced spaced. This traits are essential for observations in maize breeding programs to obtain high yielding varieties in reduced spacing. In conclusion, the physiological (PN, CE, WUE, Ci, Gs), morphological (EIH, SD, LA) and productive (NE, GME) traits provide gains in maize grain yield via indirect selection when the crop is subjected to 40 cm row spacing.


Weed Science ◽  
2012 ◽  
Vol 60 (2) ◽  
pp. 193-198 ◽  
Author(s):  
P. Marquardt ◽  
C. Krupke ◽  
W. G. Johnson

Glyphosate-resistant (GR) volunteer corn has emerged as a problematic weed in corn:soybean rotational systems, partly because of the rapid increase in adoption of corn hybrids that contain traits for both glyphosate and insect resistance. Volunteer GR corn can decrease soybean yields. The objectives of this study were to quantify the impact of volunteer corn on soybean growth and yield and determine how volunteer corn densities affect western corn rootworm (WCR) emergence. Volunteer corn seed was hand-planted at targeted densities of 0.5, 2, 4, 8, 12, and 16 seeds m−2at soybean planting and 21 d after planting to evaluate both early- and late-emerging cohorts. WCR emergence was assessed with the use of field emergence traps placed over individual corn plants in the 0.5- and 16-plants-m−2plots in 2008 and 2009. In 2010, WCR emergence traps were also placed over individual and clumped volunteer corn plants at densities of two and eight plants m−2. Soybean yield reductions ranged from 10 to 41% where early-emerging volunteer corn densities ranged from 0.5 to 16 plants m−2. No soybean yield loss occurred with the late-emerging cohort of volunteer corn. Twice as many adult WCRs emerged from a single volunteer corn plant growing at densities of 8 and 16 plants m−2, compared with plots containing 0.5 and 2 plants m−2. These results demonstrate that controlling volunteer corn will not only prevent soybean yield loss, but also may reduce the risk of WCR larval survival after exposure to Bt (Bacillus thuringiensisBerliner derived) corn.


1986 ◽  
Vol 66 (3) ◽  
pp. 453-464 ◽  
Author(s):  
D. M. BROWN

Summer dry spells in some areas of southern Ontario during the last decade have increased interest in supplemental irrigation. Field studies were conducted in a 2500 heat unit area of southern Ontario on Orthic/Brunisolic Grey Brown Luvisol soils to determine the yield response of field corn (Zea mays L.) to irrigation in midsummer when combined with increased plant density and N rates. The yield responses, phenological records and soil moisture measurements are to be used in the calibration and validation of a corn yield estimation model, to be published in a subsequent paper. Two to four irrigations were applied each year using the line method when soil moisture pressure potential reached −40 to −60 kPa at 22.5 cm depth. Development stages were unaffected by irrigation. Yield increases from irrigation were directly proportional to water applied in midsummer and the intensity of dry weather. Yields increased with plant density in 4 of the 5 yr and were usually consistent over irrigation levels. Additional nitrogen above the recommended rate increased yields in 1982 and 1983, decreased yields in 1981, and resulted in no differences the other two years. In years of positive response to extra nitrogen, there was usually a greater response with irrigation and the responses were greatest at high plant density and for the longer season hybrids. Harvest indices decreased as irrigation amount increased and were exceptionally high in 1983.Key words: Corn, Zea mays L., line-source irrigation, plant population, nitrogen, harvest index


2021 ◽  
Vol 12 ◽  
Author(s):  
Daljeet S. Dhaliwal ◽  
Elizabeth A. Ainsworth ◽  
Martin M. Williams

Over the last six decades, steady improvement in plant density tolerance (PDT) has been one of the largest contributors to genetic yield gain in field corn. While recent research indicates that PDT in modern sweet corn hybrids could be exploited to improve yield, historical changes in PDT in sweet corn are unknown. The objectives of this study were to: (a) quantify the extent to which PDT has changed since introduction of hybrid sweet corn and (b) determine the extent to which changes over time in PDT are associated with plant morpho-physiological and ear traits. An era panel was assembled by recreating 15 sugary1 sweet corn hybrids that were widely used at one time in the United States, representing hybrids since the 1930s. Era hybrids were evaluated in field experiments in a randomized complete block design with a split-plot arrangement of treatments, including hybrid as the main factor and density as the split-plot factor. Plant density treatments included “Low” plant density (9,900 plants/ha) free of crowding stress or “High” plant density (79,000 plants/ha) with crowding stress. On average, per-area marketable ear mass (Mt/ha) increased at a rate of 0.8 Mt/ha/decade at High densities, whereas per-plant yield (i.e., kg/plant) remained unchanged over time regardless of the density level. Crate yield, a fresh market metric, improved for modern hybrids. However, processing sweet corn yield metrics like fresh kernel mass and recovery (amount of kernel mass contributing to the fresh ear mass) showed modest or no improvement over time, respectively. Modern sweet corn hybrids tend to have fewer tillers and lower fresh shoot biomass, potentially allowing the use of higher plant density; however, plant architecture alone does not accurately predict PDT of individual hybrids.


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