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Breeding against mycorrhizal symbiosis: Modern cotton (Gossypium hirsutum L.) varieties perform more poorly than older varieties except at very high phosphorus supply levels
WANG Xin-xin, ZHANG Min, SHENG Jian-dong, FENG Gu, Thomas W. KUYPER
2023, 22 (3): 701-715.   DOI: 10.1016/j.jia.2022.08.004
Abstract276)      PDF in ScienceDirect      

Cotton (Gossypium hirsutum L.) is an important fiber cash crop, but its root traits related to phosphorus (P) acquisition, including mycorrhizal root traits, are poorly understood.  Eight cotton varieties bred in northwestern China that were released between 1950 and 2013 were grown in pots with or without one arbuscular mycorrhizal fungal (AMF) species (Funneliformis mosseae) at three P supply levels (0, 50 and 300 mg P as KH2PO4 kg–1).  Eleven root traits were measured and calculated after 7 wk of growth.  The more recent accessions had smaller root diameters, acquired less P and produced less biomass, indicating an (inadvertent) varietal selection for thinner roots that provided less cortical space for AMF, which then increased the need for a high P fertilizer level.  At the two lower P levels, the mycorrhizal plants acquired more P and produced more biomass than non-mycorrhizal plants (3.2 vs. 0.9 mg P per plant; 1.8 vs. 0.9 g biomass per plant at P0; 14.5 vs. 1.7 mg P per plant; and 4.7 vs. 1.6 g biomass per plant at P50).  At the highest P level, the mycorrhizal plants acquired more P than non-mycorrhizal plants (18.8 vs. 13.4 mg per P plant), but there was no difference in biomass (6.2 vs. 6.3 g per plant).  At the intermediate P level, root diameter was significantly positively correlated with shoot biomass, P concentration and the P content of mycorrhizal plants.  The results of our study support the importance of the outsourcing model of P acquisition in the root economics space framework.  Inadvertent varietal selection in the last decades, resulting in thinner roots and a lower benefit from AMF, has led to a lower productivity of cotton varieties at moderate P supply (i.e., when mycorrhizal, the average biomass of older varieties 5.0 g per plant vs. biomass of newer varieties 4.4 g per plant), indicating the need to rethink cotton breeding efforts in order to achieve high yields without very high P input.  One feasible way to solve the problem of inadvertent varietal selection for cotton is to be aware of the trade-offs between the root do-it-yourself strategy and the outsourcing towards AMF strategy, and to consider both morphological and mycorrhizal root traits when breeding cotton varieties.

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Food safety regulatory systems in Europe and China: A study of how co-regulation can improve regulatory effectiveness
Kevin Chen, WANG Xin-xin, SONG Hai-ying
2015, 14 (11): 2203-2217.   DOI: 10.1016/S2095-3119(15)61113-3
Abstract2325)      PDF in ScienceDirect      
Food safety has received a great deal of attention in both developed and developing countries in recent years. In China, the numerous food scandals and scares that have struck over the past decade have spurred significant food safety regulatory reform, which has been increasingly oriented towards the public-private partnership model adopted by the Europe Union’s (EU) food safety regulatory system. This paper analyzes the development of both the EU’s and China’s food safety regulatory systems, identifies the current challenges for China and additionally considers the role of public-private partnership. The success of co-regulation in the food regulatory system would bring significant benefits and opportunities for China. Finally, this paper recommends additional measures like training and grants to improve the private’s sector effectiveness in co-regulating China’s food safety issues.
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