Reproductive sink of sweet corn in response to plant density and hybrid

Authors: Williams, Martin

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2017
Publication Date: 1/1/2018
Citation: Williams II, M.M. 2018. Reproductive sink of sweet corn in response to plant density and hybrid. HortScience. 53:28-32.

Interpretive Summary: Improvement in corn plants’ ability to tolerate greater crowding has increased grain yield for decades. Based on research of yellow-kernel hybrids, sweet corn’s ability to tolerate crowding has lagged in comparison to grain corn. This research tested if the same were true of today’s white-kernel sweet corn hybrids. We found performance of white-kernel hybrids was below average and none of the commercially available hybrids have high tolerance to crowding. The impact of this work is that it provides sweet corn breeders, growers, and processors with knowledge essential to maximizing profitability of white-kernel sweet corn production.

Technical Abstract: Improvements in plant density tolerance have played an essential role in grain corn yield gains for ~80 years; however, plant density effects on sweet corn biomass allocation to the ear (the reproductive ‘sink’) is poorly quantified. Moreover, optimal plant densities for modern white-kernel shrunken-2 (sh2) hybrids is unknown. The objectives of the study were to 1) quantify the effect of plant density and hybrid on the reproductive sink of sweet corn, and 2) determine optimal plant densities for white-kernel sh2 sweet corn. Field experiments were conducted across two years on 10 white-kernel sh2 hybrids grown at plant densities ranging from 4.3 to 8.6 plants m-2. Increasing plant density negatively influenced reproductive sink characteristics of individual sweet corn plants, including linear decreases in ear shoots plant-1, marketable ears plant-1, ear length, filled ear length, ear mass plant-1, and kernel mass plant-1. Reproductive traits varied widely among hybrids, including ear mass (15.6 to 20.6 Mt ha-1) and recovery (32.3 to 42.4%), which is the contribution of fresh kernel mass to total ear mass. Hybrids had a common response to plant density, whereby ear yield was optimized at 5.5 plants m-2 and gross profit margin was optimized at 6.1 plants m-2. Plant density data from 586 growers’ fields suggests current seeding rates have optimized the reproductive sink size for today’s white-kernel sh2 hybrids. However, room exists for improving plant density tolerance, yield, and profitability.