Analysis of Traits Related to Weed Competitiveness in Sweet Corn (Zea mays L.)

Abstract

Weed management in sweet corn can be costly; genetic improvements in sweet corn competitiveness may reduce this expense. Competitive ability can exist as weed suppressive ability (WSA), or crop tolerance (CT). Previous studies in corn have found year of hybrid release, maturity, plant height, leaf angle and leafiness may affect WSA, while hybrid era, maturity, and plant height may affect CT. However, many of these studies were limited to very few genotypes. The objective of this study was to assess the effects of phenomorphological traits on sweet corn competitiveness and the inheritance of these traits. An incomplete half-diallel from seven historic sweet corn inbred lines of varying morphologies was evaluated in a split-block randomized complete block design in three environments. Forage sorghum was interplanted in half of the blocks to act as a model weed. Significant differences among hybrids were generally found for both phenomorphological traits and traits measuring WSA and CT, such as sorghum biomass and yield stability, respectively. Crop plant height was most predictive of WSA and CT. In this set of genotypes, competitive ability may be passed with reasonable fidelity from parent to offspring, suggesting that sweet corn could be bred for competitive ability.

Genetic Variation and Phenotypic Response of 15 Sweet Corn (Zea mays L.) Hybrids to Population Density

“…P39 also had the greatest positive GCA effect for tiller number. These results also confirm Zystro et al's [27] finding that P39 was the least competitive.…”

“…In particular, publicly-available inbreds C68, C40 and Ia5125 could be utilized by sweet corn breeders to increase density tolerance. These results, taken in consideration with those of Zystro et al [27], suggest the feasibility of breeding sweet corn for high density tolerance and increased weed competitiveness for organic systems.…”

“…Tiller number, on the other hand, was negatively correlated with plant height, yield and ear width, indicating that a tall plant with minimal tillers may be a desired phenotype for higher density tolerance. Correlation is not causation, however, and as noted by Zystro et al [27], plant height and tiller number may be the observed trait that is linked to unmeasured factors increasing high density tolerance.…”

“…In a previous experiment, Zystro et al [27] analyzed the effects of phenomorphological traits of the same inbred parents used in the present study on sweet corn weed competitiveness, and found plant height to be highly correlated with increased weed suppressive ability. In the present study, plant height was also highly correlated with yield and ear width (Table 4).…”

“…Zystro et al [27] also used a similar diallel analysis, identifying C68 as the most competitive inbred due to its height and its production of hybrids with the highest yields and lowest weed biomass.…”