TITLE:
Variable Responses to CO2 of the Duration of Vegetative Growth and Yield within a Maturity Group in Soybeans
AUTHORS:
James A. Bunce
KEYWORDS:
Soybean, Elevated CO2, Yield, Flowering
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.13,
September
16,
2016
ABSTRACT: Prior experiments in indoor chambers and in the
field using free-air carbon dioxide enrichment (FACE) systems indicated
variation among soybean cultivars in whether and how much elevated CO2 prolonged vegetative development. However, the cultivars tested differed in
maturity group, and it is not known whether variation exists in CO2 effects on the duration of vegetative growth within a maturity group. In these
experiments, a total of five soybean cultivars of maturity group IV were grown
at ambient and elevated CO2 in the field in Maryland, USA using FACE
systems, over three years. The time of first flowering, the time of the first
open flowers at the apex of the main stem, the total number of main stem nodes
at maturity, and seed yield were recorded. In each year of the study, there
were cultivars in which elevated CO2 did not affect the duration of
vegetative growth or the main stem node number, and other cultivars in which
elevated CO2 prolonged vegetative growth and increased the number of
main stem nodes and seed yield at maturity. The stimulation in yield by
elevated CO2 was highly correlated with the increase in the number
of main stem nodes, indicating that CO2 effects on the duration of
vegetative growth may be important in adapting soybean to higher atmospheric CO2.