ABSTRACT
Normal oleic peanuts are often found within commercial lots of high oleic peanuts when sampling among individual kernels. Kernels not meeting high oleic threshold could be true contamination with normal oleic peanuts introduced via poor handling, or kernels not meeting threshold could be immature and not fully expressing the trait. Beyond unintentional mixing, factors contributing to variation in oleic acid concentration in peanut kernels include market type, environment, maturity and/or kernel size; however, the relative influence of these factors, and their interactions, is not quantitatively well understood on the single kernel level. To better understand these factors while simultaneously excluding variation from unintentional mixing, seed from a high oleic spanish cultivar and seed from a high oleic runner cultivar were carefully purified via NIR technology. The purified seed were planted in environmentally controlled test plots to analyze the progeny for oleic acid chemistry. Post flowering, plot sections were either chilled (3.8 -5.0 C below ambient), maintained at ambient or heated (3.8-5.0 C above ambient) in the pod zone to characterize soil temperature effects on oleic acid chemistry development. Fully randomized (4 reps) plots included the purified high oleic spanish and runner cultivars, three soil temperatures, seed maturity (profile board), commercial kernel size classifications, and a late season flower termination protocol. At harvest, the oleic acid concentration of approximately 24,000 individual kernels were measured via NIR technology. Market type, temperature, maturity and size had a significant effect on high oleic chemistry among kernels. Late season flower termination significantly, and positively, influenced high oleic chemistry of runner peanuts, minimized the number of immature kernels not meeting high oleic threshold and resulted in elevated and more consistent distributions in this key chemistry; distributions that were more similar to those of the more botanically determinate, but lower yielding, spanish market type. Data from this study improves our understanding of expected natural variation in high oleic chemistry and suggests late season flower termination of runner peanuts is a viable strategy to maximize high oleic chemistry on the single kernel level.
Measurements of Oleic Acid among Individual Kernels Harvested from Test Plots of Purified Runner and Spanish High Oleic Seed