Abstract
Early vigour traits of wheat composite cross populations (CCPs) based on high yielding (Y) or high quality (Q) or Y*Q varietal intercross evolving under organic or conventional conditions in parallel populations were studied hydroponically. To eliminate storage and year effects, frozen F6, F10, F11 and F15 seeds were multiplied in one field, resulting in the respective Fx.1 generations. This eliminated generation and growing system effects on seed size for the F6.1 F10.1 and F15.1. Due to a severe winter kill affecting the F11, the generation effect persisted, leading to larger seeds and markedly different seedling traits in the F11.1 compared to the F10.1 and F15.1. Seedling traits were similar among parallel populations. Shoot length and weight increased in both systems until the F11.1 across farming systems and remained constant thereafter. Over time, seminal root length and root weight of organic CCPs increased and total- and specific- root length decreased significantly compared to the conventional CCPs. Rooting patterns under organic conditions suggests better ability to reach deeper soil nutrients. In both systems, Q and YQ CCPs were more vigorous than Y CCPs, confirming genetic differences among populations. Overall, heterogeneous populations appear very plastic and selection pressure was stronger in organic systems.
Highlights
In both systems, Q and YQ composite cross populations (CCPs) were more vigorous than Y CCPs, confirming genetic differences among populations
Since the few years. In 2006/07 (F6) (2006/07), each CCP was split into two parallel populations (I and II) within each farming system to determine the changes of the CCPs within the system and between systems
Most seedling traits were similar among the parallel populations, suggesting that evolution was driven by the initial genetic composition and farming system
Summary
Q and YQ CCPs were more vigorous than Y CCPs, confirming genetic differences among populations. An alternative is to develop agricultural systems with an inherent capacity to adapt to environmental changes and that contribute to the protection of soil organic content and structure[3,4]. This requires a major rethinking of breeding methods and redesigning of farming systems. Morphological and agronomic studies with these CCPs (F5 - F15) revealed that genetic variability is still high in the CCPs, even after 11 generations[31] and unpublished molecular analyses by our laboratory confirm continuous recombination events in the populations This allows for changes in their genetic make-up over time through selection and recombination and enables adaptation to their growing conditions[31]. In conditions of water-stress or drought the CCPs (F14, 2014/15) have out-yielded modern cultivars[31]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
