Statistical modeling of phenotypic plasticity under abiotic stress in Triticum durum L. vs. T. aestivum L. genotypes

Authors: Jaradat, Abdullah

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2018
Publication Date: 8/4/2018
Citation: Jaradat, A.A. 2018. Statistical modeling of phenotypic plasticity under abiotic stress in Triticum durum L. vs. T. aestivum L. genotypes. Agronomy. https://doi.org/10.3390/agronomy8080139.
DOI: https://doi.org/10.3390/agronomy8080139

Interpretive Summary: Durum and bread wheat production demonstrated large increases due to unprecedented productivity growth from the Green Revolution. This benefited both producers and consumers of wheat through low production costs and low food prices. However, future challenges to the role of wheat in global food security will be shaped by its potential to produce larger yields and better nutritional quality while increasingly withstanding multiple biotic and abiotic stresses. A long-term field experiment was implemented to explore how both wheat species may respond to increasing stress conditions. A second objective of the study suggests a method of increasing wheat yield and its nutritional quality under decreasing resources due to shorter growing season and higher plant competition for soil water and nutrients. These objectives can be achieved by adjusting plant traits to contribute more to larger plant biomass that can be directed more towards more grains per unit area, without substantially affecting grain weight. Thus, this will maintain or even improve nutritional quality of its protein and nutrient contents. The data and information generated by the study would be of value to wheat breeders and agronomists in their quest for better adapted wheat to abiotic stress. In addition, this information will benefit farmers who can manipulate agronomic practices in the field to achieve higher yields and better quality.

Technical Abstract: Future medium- and long-term challenges to the role of durum and bread wheat in global food security will be shaped by its potential to produce larger yields and better nutritional quality, while increasingly adapting to multiple biotic and abiotic stresses in view of global climate change. Given no systematic progress in harvest index since the early 1990s, future wheat yield gains will depend more on increased biomass, spike fertility index and spike harvest index. There is a dearth of information on comparative assessment of phenotypic plasticity in both wheat species under long-term multiple abiotic stresses. To assess the benefit or cost of plasticity in wheat, it is imperative to estimate the relationship between plasticity of each yield component and grain yield per se, as well as other traits associated with grain yield. Phenotypic plasticities of durum and bread wheat genotypes were assessed under increasing abiotic and edaphic stresses for six years; validation and confirmatory factor models revealed major differences in phenotypic plasticities between the two species that can be attributed to differences in ploidy level, length of domestication history, or constitutive differences in resources allocation. A new wheat ideotype can be designed for larger grain yield potential under abiotic stress by manipulating yield components affect kernels per unit area (e.g., to tillering, number of florets per spikelet, and eventually spike fertility and harvest indices) without affecting kernel weight, thus raising harvest index beyond its current maximum.