Root traits and root biomass allocation impact how wheat genotypes respond to organic amendments and earthworms

Abstract

Plant-soil biological interactions are increasingly recognized as a key feature of agroecosystems, promoting both crop and soil health. However, the effectiveness of plant-soil synergies is likely modulated by both root system characteristics and soil management impacts on soil biological communities. To successfully manage for plant-soil interactions, we need to better understand how crops respond to changes in soil management, especially in terms of belowground investment. Specifically, crop genotypes that exhibit reduced plasticity in root growth and investment may not be able to take full advantage of changes in soil biological activity associated with soil health promoting practices. We hypothesized that genotypes with greater belowground investment respond more, in terms of plant growth and crop nitrogen (N) uptake, to compost and earthworm additions, agronomic factors commonly associated with soil health. We evaluated four spring wheat (Triticum aestivum) genotypes with distinct breeding and environmental histories, and one progenitor of wheat (Aegilops tauschii) under low soil fertility conditions in the greenhouse for differences in belowground root biomass and architecture. We then determined how these belowground traits influenced genotype response to additions of compost and earthworms. Measurements included plant growth, biomass, grain yield, root characteristics, plant N uptake, and soil N. Overall, in unamended soils, genotypes differed in above and belowground phenotypic traits. In general, Ae. tauschii had three times greater root: shoot (R:S) ratio, root length, and root biomass relative to wheat genotypes. We found that genotypes with higher R:S ratios responded more positively to compost additions compared to those with lower R:S ratios, particularly in terms of plant aboveground biomass, N uptake and soil N-cycling, and also exhibited greater plasticity in root morphology. Consequently, while higher R:S genotypes had relatively poorer yields in unamended soils, they outperformed lower R:S genotypes in total seed weight under compost treatments. Our findings suggest that genotypes with greater belowground investment may be better able to take advantage of soil health promoting practices, such as the use of organic amendments. These results highlight the need to consider soil management practices (and associated biological communities) in parallel with root phenotypic plasticity when evaluating wheat lines for improvements in plant-soil synergies.

Durum wheat salt stress tolerance is modulated by the interaction between plant genotypes, soil microbial biomass, and enzyme activity

“…The exuded molecules form rhizodeposits that interact with soil microorganisms, thereby affecting the enzymatic activity differently according to genotypes (Zuo et al, 2014). This finding agrees with other studies showing significant effect of wheat genotypes on soil parameters (e.g., MBC and MBN), particularly those characterized by specific root lengths and the proportion of coarse roots (Corneo et al, 2016;Junaidi et al, 2018).…”

“…Both genotypes, 'Maali' and 'Agili Glabre', might accumulate more microorganisms near to their roots, thus having beneficial effects on plants, including mycorrhizal fungi and N fixers (Bever, 2015), increasing N mineralization at tillering and flowering. Besides, soil available N dynamic depends on genotype uptake aptitude (Junaidi et al, 2018). Plants compete with nitrifying microorganisms with a rapid uptake, dense root systems, or regulation of oxygen availability (Glaser et al, 2010).…”

Genotypic variation in maize (Zea mays) influences rates of soil organic matter mineralization and gross nitrification

“…Taken together, these findings indicate that maize root and shoot growth can be plastic in response to nutrient status of soil (Junaidi et al, 2018), and that their response to management can also depend on nutrient status of soil and plant genotype. This indicates another potential selection/breeding target for specific managements.…”

Accumulating crop functional trait data with citizen science

“…While comprehensive ecological analyses of our dataset are beyond the scope of our methodological research here, this type of crop trait data supports myriad novel hypotheses in both theoretical and applied plant science research. From a theoretical perspective, citizen-science-based data on crop traits (particularly ITV) could be employed in studies evaluating: (i) hypotheses on if or how artificial selection has led crops to deviate from “universal” plant trait spectra 9,13,33 ; and (ii) the intentional and unintentional consequences of domestication through analyses of crop trait dimensionality 21,34 . From an applied perspective, such data has immediate implications for: (iii) refining process-based models of crop performance under environmental change and with agroecological practices 35 ; (iv) better understanding genotype-by-environment responses of crops to environmental conditions 36 ; and (v) informing farmer selection of crop genotypes in participatory plant breeding programs 37 .…”