ARS | Publication request: Sugarcane Leaf Photosynthesis and Growth Characters during Development of Water-Deficit Stress

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 28, 2012
Publication Date: April 22, 2013
Repository URL: http://handle.nal.usda.gov/10113/56467
Citation: Zhao, D., Glaz, B.S., Comstock, J.C. 2013. Sugarcane Leaf Photosynthesis and Growth Characters during Development of Water-Deficit Stress. Crop Science. 53:1066-1075.

Interpretive Summary: Approximately 20% of sugarcane in Florida grows on sand soils. Yield and profitability of sugarcane grown on sand soils are much lower than on organic (muck) soils. Development of high-yielding sugarcane genotypes for sand soils is difficult due to biotic and abiotic stresses. Water deficit during the sugarcane formative growth phase may be one of the abiotic stresses and limit growth and yield on the sand soils. A greenhouse study was conducted in 2009 and 2010 to compare sugarcane genotype responses to water deficit stress on a sand soil. Treatments included two sugarcane genotypes (CP 01-2390, sand soil adapted and CP 80-1743, muck soil adapted) and two water regimes (well watered and water deficit stress). All plants were well watered before initiating the water stress. Water was withheld from the water stress treatment pots when plants reached 7 to 8 leaves on the primary stem. During the stress treatment, plant growth and leaf photosynthetic components were measured. Final green leaf area and shoot biomass were determined at the end of the experiment. Water stress reduced stomatal conductance, leaf net photosynthetic rate, and green leaf are, resulting in reduced shoot biomass. CP 01-2390 was superior to CP 80-1743 in most measured physiological and growth traits under the well watered and water stress conditions suggesting that selection of genotypes with tolerance to water stress while improving irrigation management will help improve sugarcane yields on sand soils. Physiological and growth traits, such as stomatal conductance, leaf net photosynthetic rate, green leaf area, tillering, and plant height, may be useful for early detection of water stress and evaluation of water stress tolerant genotypes in a sugarcane cultivar development program.

Technical Abstract: Yield and profitability of sugarcane grown on sand soils are much lower than on organic soils in Florida due to biotic and abiotic stresses. A greenhouse study was conducted using a sand soil to identify effects of water deficit stress (WS) during sugarcane early growth on leaf photosynthetic components, plant growth, and dry matter accumulation. Treatments included two sugarcane genotypes (CP 01-2390 and CP 80-1743) and two water regimes (well watered [WW] and WS). All plants were well watered before initiating WS. Water was withheld from the WS pots when plants reached 7 to 8 leaves on the primary stem. During the WS treatment, plant growth and leaf photosynthetic components were measured. Final green leaf area (GLA) and shoot biomass were determined at the end of the experiment. Water stress depressed leaf relative chlorophyll level (SPAD), stomatal conductance (gs), leaf net photosynthetic rate (Pn), transpiration rate (Tr), transpiration use efficiency (TUE) of photosynthesis, and GLA, resulting in reduced shoot biomass. CP 01-2390 was superior to CP 80-1743 in most measured physiological and growth traits under the WW and WS conditions, suggesting that selection of genotypes with tolerance to WS while improving irrigation management will improve sugarcane yields on sand soils. Physiological and growth traits, such as SPAD, gs, Pn, Tr, TUE, GLA, tillering, and stalk length may be useful for early detection of WS and for evaluation of sugarcane genotypes in the stress tolerance.