Location: Sugarcane Field StationTitle: Sugarcane genotype variation in leaf photosynthesis properties and yield as affected by mill mud application
|IREY, MICHAEL - Us Sugar Corporation|
|HU, CHEN-JIAN - Us Sugar Corporation|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2014
Publication Date: 2/16/2015
Citation: Zhao, D., Glaz, B.S., Irey, M., Hu, C. 2015. Sugarcane genotype variation in leaf photosynthesis properties and yield as affected by mill mud application. Agronomy Journal. 107:506-514.
Interpretive Summary: Sugarcane is an important crop in south Florida with an economic impact of more than $3 million in the regain. Approximately 80% of sugarcane in Florida is grown on muck soils and 20% on sand soils. Although sugarcane yield responses to mill mud on sand soils for a specific cultivar have been studied, little is known if there are any differences in some physiological traits among sugarcane genotypes and their responses to mill mud application. We hypothesize that measurements of relative leaf chlorophyll, leaf photosynthesis, and leaf hyperspectral reflectance may be used to better understand physiological aspects of yield responses to mill mud application and to identify genotype differences in the physiological and yield traits for elite cultivar selection. To identify sugarcane genotypic responses to mill mud application on a sand soil in leaf spectral reflectance, relative chlorophyll level, and photosynthetic characteristics and to determine relationships between these physiological traits and yield components, we measured leaf spectra, chlorophyll level, and photosynthesis during growing seasons and final yield components of seven sugarcane genotypes and one Erianthus on a Margate sand soil with and without mill mud added prior to planting. Mill mud application was mainly reduced leaf reflectance at 560 and 710 nm, increased leaf chlorophyll levels, photosynthesis, and sucrose yield for the first-ratoon crop but not for the second-ratoon crop. Genotypic differences in most physiological traits and yield components were also detected. Most physiological traits correlated with cane and sucrose yields under the without mill mud added condition. Genotypic variation in physiological and yield responses to mill mud application and their interactions indicated that selection of sandland well adapted genotypes based on leaf physiological traits and yield performance will improve sugarcane yield sustainability on sand soils in Florida.
Technical Abstract: Variability in yield among sugarcane (a complex hybrid of Saccharum spp.) genotypes grown with and without mill mud application on sand soils in Florida has been documented, but little is known about what causes yield differences and if there are any relationships between yield components and physiological parameters. This study determined responses of leaf relative chlorophyll level (SPAD readings), photochemical efficiency of photosystem II in dark-adapted leaves (Fv/Fm), leaf stomatal conductance (gs), net photosynthetic rate (Pn), transpiration rate (E), difference between leaf and air temperatures (Tl–Ta), and spectral reflectance in one Erianthus (Erianthus arundinaceus) and seven sugarcane genotypes and their relationships to yield components across genotypes. Reflectance, Fv/Fm, SPAD, gs, Pn, E, and Tl-Ta were measured on leaves at the top visible dewlap during the first- and second-ratoon crops on a Margate sand soil with or without mill mud added prior to planting. Mill mud application reduced leaf reflectance at wavelengths of 560 and 710 nm and significantly increased leaf SPAD, gs, Pn, and E in the first-ratoon crop only. Genotypic differences were detected in most physiological traits and yield components. Most physiological traits correlated with cane and sucrose yields when no mill mud was added. Genotypic variation in physiological and yield responses to mill mud application and genotype × mill mud interactions in yields indicated that augmenting yield selection of genotypes with leaf physiological traits will improve sugarcane breeding programs for sand soils.