|ZURWELLER, BRENDAN - University Of Florida|
|ROWLAND, DIANE - University Of Florida|
|TILLMAN, BARRY - University Of Florida|
|MIGLIACCIO, KATIE - University Of Florida|
|WRIGHT, DAVID - University Of Florida|
|ERICKSON, JOHN - University Of Florida|
Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2018
Publication Date: 1/21/2018
Citation: Zurweller, B., Rowland, D., Tillman, B., Payton, P.R., Migliaccio, K., Wright, D., Erickson, J. 2018. Assessing above-and below-ground traits of disparate peanut genotypes for determining adaptability to soil hydrologic conditions. Field Crops Research. 219:98–105.
Interpretive Summary: The objectives of this field research trial were to: (i) assess differences in root and shoot growth and their relationship to pod yield among peanut sub-species displaying different growth habits and (ii) characterize the possible interactions of these traits with environmental variability under various irrigation management strategies relevant for a humid climate. We hypothesized that differences in key root growth traits exist among peanut sub-species which would provide more or less resilience to water deficit stress conditions, and that pod yield production would be negatively related to below-ground traits due to trade-offs in energy partitioning between root and shoot systems. Furthermore, we suspected that above- and below-ground traits would interact with the range of irrigation treatments implemented in this study because of the disparate descent of these genotypes which may be adapted to different soil hydrologic condi- tions. We found that indeed, there were differences in root architectures between the growth types with erect types having longer, finer roots with more lateral roots compared to coarser roots in recumbant growth types. As suspected, pod yield was negatively correlated with total root mass, suggesting that energy not expended on excess root development was potentially used for additional pod yield. The information gained from this study will provide knowledge of both above- and below-ground biomass partitioning between sub- species hypogaea and fastigiata that could be used for: i) selecting germplasm best adapted to a range in hydrologic conditions; and ii) evaluating the feasibility of utilizing reduced irrigation management in humid production regions like the US Southeast. For most of the traits measured, there was little to no correlation.
Technical Abstract: Crop water deficit stress contributes to more global crop loss than any other abiotic or biotic stress. To help achieve greater crop production under water scarcity, much emphasis has been placed on identifying irrigation management practices and crop genotypes for improving water stress resilience in agriculture. The objectives of this research were to: (i) quantify genotypic differences between subspecies of peanut (Arachis hypogaea L.), hypogaea and fastigiata, in root and canopy architecture, and evaluate their relationship with pod yield; and (ii) examine the response of these above- and below-ground traits of peanut genotypes to various irrigation regimes conducted in a humid climate. Field trials were implemented in 2015 and 2016 in north central Florida. Irrigation treatments included 1.9 cm per application (100%); a primed acclimation treatment consisting of 1.1 cm of water per application until mid-bloom and then 1.9 cm of water for the remainder of the season (60% PA); 1.1 cm of water per application for the entire season (60%); and a rainfed only (RF) system. Peanut genotypes included two Valencia (Arachis hypogaea L. subsp. fastigiata Waldron) market types COC 041 (PI 493631) and New Mexico Valencia C (NMVC), and two runner (Arachis hypogaea L. subsp. hypogaea) commercial cultivars FloRun™ ‘107' and TUFRunner™ ‘511'. Genotypic total root length (TRL) and leaf area index (LAI) did not interact with irrigation treatments, but decreasing the total amount of irrigation over the growing season reduced LAI and pod yield, with no impact on TRL growth or distribution to 80 cm of soil depth. Genotypic effects influenced the TRL development over the growing season, and genotypes of subspecies fastigiata had greater TRL deep in the soil profile. However, all genotypes had similar amounts of root total surface area (TSA) distribution to 80 cm of soil depth. A positive relationship was observed between pod yield and maximal LAI in both study years, although this relationship was weak (R2=0.15) in 2016 when greater water deficit stress severity occurred during reproductive growth. A significant low coefficient of determination of 0.15 and 0.20 was observed for the negative relationship between pod yield and maximal TRL in 2015 and 2016, respectively. The lack of interaction between irrigation and genotype for pod yield demonstrates that peanut genotypes with more prolific root growth at depth may not necessarily have an advantage for increased amounts of water acquisition and utilization that are translated into yield.