Reading Peanut Leaves for the Future Quality.

The maturity of peanut seed effects germination and potentially seedling vigor. The quality of peanut seed is greatly influenced by the available calcium (Ca) and boron (B). The objective of this research was to determine if pre-harvest tissue nutrient concentrations could predict subsequent seed quality. The research was a randomized complete block with four cultivars, three harvests, and four replications, with cultivars as main plots and harvest dates as subplots. We characterized 1) leaf and seed nutrient concentrations at multiple harvest dates, 2) germination rate and root characteristics of subsequent peanut seed, and 3) the correlation of in-season tissue nutrient concentrations to peanut seed germination and seedling root characteristics. The trials were located at the West Florida Research and Education Center in Jay, FL for three site-years during 2015 and 2016. Nutrient concentrations in leaf tissue were assessed immediately prior to digging. Using the peanut profile board and the Digital Imaging Model, pods were classified as mature and immature based on mesocarp color. Nutrient concentrations of kernels from each maturity class were also determined at each digging date. Germination was evaluated using a thermal gradient table and, in 2016, rhizotron chamber tests were employed to determine rooting characteristics of subsequent seed. During all three site-years, leaf Ca concentration increased with increasing aGDDs at harvest. For the first site year the kernel Ca concentration decreased by aGDDs, but for the two-following site-years it increased. A positive correlation between leaf B and aGDDs at harvest was observed during all three site-years, but this was not true for kernel B concentration. No correlation was observed between aGDDs and germination rate using the thermal gradient table, likely because germination capability is determined early during seed development. Although a correlation between in-season tissue nutrient concentrations and subsequent seedling vigor was not conclusive in this experiment, a more robust seedling vigor test may allow for the determination of in-season tissue nutrient concentrations as a predictive tool for seedling vigor in the future.