Assessing Current Boron Recommendations for Peanut Production through Remote Sensing, Agronomic Factors, and Seed Germination.

For peanut (Arachis hypogaea L.), boron (B) application is standard in the Virginia-Carolina (VC) region.  Boron deficiency causes stunted growth, delayed maturity and germination failure due to the “hollow heart” symptom.  Both deficiency and toxicity can cause significant yield and seed quality loss.  Current B applications are based on research in early 70’s and may not be suited for new cultivars and production practices.  The objective of this study is to assess the effectiveness of the current recommendation rates and application times for the modern peanut cultivars through remote sensing and seed germination techniques, and evaluations of yield and grading factors.  In 2014, trials arranged in a split-plot design received 0.34 and 0.56 kg ha^-1 B at beginning peg (R2), full seed (R6), and split applications between planting-R2 and planting-R6.  Cultivar ‘Bailey’ was used.  Significant (p < 0.05) tissue B content was found after each application.  At R2, tissue B content ranged from 54 to 80 mg kg^-1 when full rates where applied, to only 37 mg kg^-1 with no B application.  At R4, tissue B content was from 12.3 to 15.0 mg kg^-1 when B was applied and only 11 mg kg^-1 when it was not. In kernels, B content was from 16.1 to 18.8 mg kg^-1 with B and 14.5 mg kg^-1 without B treatment.  No differences in yield, grading factors, and seed germination were recorded in 2014.  In agreement with our hypothesis, this suggests that the current B practice in the VC region is no longer optimal for sustained peanut production and provides support  to re-evaluate this practice. In 2015, the rate and application time test is being repeated.  An additional test was included to compare 12 new and old peanut cultivars for their response to the B current application recommendations.  Remote sensing data gathered in 2015 is still being analysed for both tests.