Donald's Ideotype and growth redundancy: a pot experimental test using an old and a modern spring wheat cultivar.
Human selection for high crop yield under water-limited conditions should have led modern cereal cultivars to invest less in root biomass, be it unconsciously. To test this hypothesis we conducted a pot experiment with two spring wheat cultivars, one old and one modern, both widely grown in the semi-arid regions of China. Using the replacement series method introduced by de Wit, we showed that the older landrace (Monkhead) was significantly more competitive than the more-modern cultivar (92-46). However, when grown in pure stand, old Monkhead had grown root biomass 3.5 times modern 92-46, whereas modern 92-46 gained a 20% higher grain yield. We also found modern 92-46 significantly increased root biomass per plant and root allocation (i.e., root biomass/total individual biomass) as its frequency in mixtures decreased, whereas old Monkhead did not respond in a similar way. This result suggests that the roots of modern cultivars may have gained an ability to recognize neighboring root systems and show more plastic self-restraining response to intra-cultivar competition.
State Key Laboratory of Earth Surface Processes and Resource Ecology and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, China.
Li
L
Zhu
Da-Yong
DY
Zhang
D000222:Adaptation, Physiological; D018533:Biomass; D002681:China; D055864:Droughts; D018517:Plant Roots / Q000033:anatomy & histology / Q000502:physiology*; D012641:Selection, Genetic; D014908:Triticum / Q000033:anatomy & histology / Q000502:physiology*; D014867:Water / Q000502:physiology
D014867:Water