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2017 ASHS Annual Conference

Found in Translation: Phosphorus Availability and Mechanical Impedance Alter Sweetpotato Storage Root Length and Shape Attributes

Thursday, September 21, 2017: 5:15 PM
King's 3 (Hilton Waikoloa Village)
Arthur Q. Villordon, Louisiana State University Ag Center, Chase, LA
Michael Selvaraj, International Center for Tropical Agriculture, Cali, Colombia
Awais Khan, Cornell University, NYSAES, Geneva, NY
Don LaBonte, Louisiana State University AgCenter, Baton Rouge, LA
Based on work in plant model systems, there is evidence that point to the root tip as the site of phosphorus (P) sensing. Despite this information, very little translational research has been conducted to determine the role of P in storage root length (RL) determination in sweetpotato (Ipomoea batatas L. Lam) and other root crops. In these crop species, knowledge about the factors that determine RL is of scientific and practical importance because RL helps to determine storage root shape and sizing. Available data also implicate the role of soil mechanical impedance (soil compaction) in determining RL. First, we studied the effect of P availability on storage RL in sweetpotato cv. Bayou Belle. We found that the omission of P reduced storage RL and length:width ratio (LWR) by 45% and 43%, respectively, compared to the control treatment (P=15 ppm). Spatial omission of P progressively reduced storage RL and LWR after 50 days of growth. In a second study, the effect of a compacted layer in the bottom half of the growth medium (penetrometer resistance = 2000 kPa) was investigated in sweetpotato cvs. Bayou Belle and Beauregard. The presence of a compacted layer and P reduced storage RL by 43% and 34% in cvs. Beauregard and Bayou Belle, respectively. However, there was a cultivar-specific variation in RL in the presence of P when the compacted layer was absent. This response suggests a possible genotype-specific variation in P requirement. These results demonstrate the importance of translating relevant root architecture findings in appropriate plant models to horticultural crops. The results of the current study can lead to follow-up work that seeks to shed light on the precise mechanisms of storage root length determination in sweetpotato and other root crops.