Optimum plant density for crowding stress tolerant processing sweet corn

Authors: DHALIWAL, DALJEET - University Of Illinois; Williams, Martin

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2019
Publication Date: 9/26/2019
Citation: Dhaliwal, D.S., Williams II, M.M. 2019. Optimum plant density for crowding stress tolerant processing sweet corn. PLoS One. 14(9):e0223107. https://doi.org/10.1371/journal.pone.0223107.
DOI: https://doi.org/10.1371/journal.pone.0223107

Interpretive Summary: The U.S. leads sweet corn innovation and production globally, yet rising production costs coupled with stagnant yield and low commodity prices are creating unusual economic hardship on the sweet corn processing industry. Plant density tolerance, a trait that transformed field corn productivity, has been under-utilized in sweet corn. In collaboration with the sweet corn processing industry, on-farm experiments revealed a relatively simple approach to immediately improve yield and profitability for the sweet corn industry - by growing certain hybrids at plant densities that fully utilize their potential.

Technical Abstract: Grain yield improvement of field corn (Zea mays L.) is associated with increased tolerance to higher plant densities (i.e., crowding stress). Processing sweet corn hybrids that tolerate crowding stress have been identified; however, such hybrids appear to be under-planted in the processing sweet corn. Using crowding stress tolerant (CST) hybrids, the objectives of this study were to: (1) identify optimum plant densities; (2) quantify gaps in production between current and optimum plant densities; and (3) enumerate changes in yield and ear traits for shifting from current to optimum plant densities. Using a CST shrunken-2 (sh2) processing sweet corn hybrid, on-farm plant density trials were conducted in thirty fields across the states of Illinois, Minnesota and Wisconsin, from 2013 to 2017. Linear mixed-effects models were used to identify the optimum plant density corresponding to maximum ear mass (Mt ha-1), case production (cases ha-1), and profitability to the processor ($ ha-1). Kernel moisture, indicative of plant development, was unaffected by plant density. Several individual ear traits declined linearly with increasing plant density. Nonetheless, there was a large economic benefit to the grower and processor by using plant densities higher than current in most environments. This research shows increasing plant densities of CST hybrids could improve processing sweet corn green ear yield and processor profitability on average 1.13 Mt ha-1 and $525 ha-1, respectively.