Background: Arbuscular mycorrhizal (AM) fungi form symbiotic associations with roots in most land plants. AM symbiosis provides benefits to host plants by improving nutrition and fitness. AM symbiosis has also been associated with increased resistance to pathogen infection in several plant species. In rice, the effects of AM symbiosis is less studied, probably because rice is mostly cultivated in wetland areas, and plants in such ecosystems have traditionally been considered as non-mycorrhizal. In this study, we investigated the effect of AM inoculation on performance of elite rice cultivars (Oryza sativa, japonica subspecies) under greenhouse and field conditions, focusing on growth, resistance to the rice blast fungus Magnaporthe oryzae and productivity. Results: The response to inoculation with either Funneliformis mosseae or Rhizophagus irregularis was evaluated in a panel of 12 rice cultivars. Root colonization was confirmed in all rice varieties. Under controlled greenhouse conditions, R. irregularis showed higher levels of root colonization than F. mosseae. Compared to non-inoculated plants, the AM-inoculated plants had higher Pi content in leaves. Varietal differences were observed in the growth response of rice cultivars to inoculation with an AM fungus, which were also dependent on the identity of the fungus. Thus, positive, negligible, and negative responses to AM inoculation were observed among rice varieties. Inoculation with F. mosseae or R. irregularis also conferred protection to the rice blast fungus, but the level of mycorrhiza-induced blast resistance varied among host genotypes. Rice seedlings (Loto and Gines varieties) were pre-inoculated with R. irregularis, transplanted into flooded fields, and grown until maturity. A significant increase in grain yield was observed in mycorrhizal plants compared with non-mycorrhizal plants, which was related to an increase in the number of panicles. Conclusion: Results here presented support that rice plants benefit from the AM symbiosis while illustrating the potential of using AM fungi to improve productivity and blast resistance in cultivated rice. Differences observed in the mycorrhizal responsiveness among the different rice cultivars in terms of growth promotion and blast resistance indicate that evaluation of benefits received by the AM symbiosis needs to be carefully evaluated on a case-by-case basis for efficient exploitation of AM fungi in rice cultivation.
Spain is the second highest rice-producing country in the European Union, with approximately 105,000 ha used to grow this crop. The major rice-producing regions in Spain are Andalusia, Extremadura, Catalonia, and Valencia, followed by Aragon and Navarre. The main soil texture throughout Spanish rice areas is silty clay loam, with alkaline soils (pH > 7.5)—except in the Extremadura area (pH = 5.5–6)—and a low organic matter content. Water quality in terms of salinity is acceptable, although in some coastal rice areas salinity issues occasionally appear to be a determining factor for high yield achievement. According to a survey carried out on farmers and technicians, the most problematic weeds found in rice crops today in Spain are Echinochloa spp., Leptochloa spp., and Cyperus difformis. Most of the currently authorized herbicides can be classified according to two modes of action: ALS-inhibiting and ACCase-inhibiting. Repeated field applications of herbicides with the same mode of action have resulted in the selection of herbicide-resistant weeds. At present, resistance has been confirmed in different regions of Spain to ALS inhibitors in Echinochloa spp., Leptochloa spp., and Cyperus difformis, and to ACCase inhibitors in Echinochloa spp. and Leptochloa spp. The mechanism of resistance in these species is a mutation in the target site of these herbicides. Several mutations have been found in the ALS gene, both in Echinochloa spp. and Cyperus difformis, distributed in the different rice-growing regions considered in this work. ACCase gene mutations have been mainly found in Leptochloa spp. individuals from Extremadura and Valencia. These different mutations have resulted in different patterns of cross-resistance to ALS- and ACCase-inhibiting herbicides. It is likely that the repeated use of these two modes of action in rice will result in the evolution of more resistant weed populations. The possible availability of new herbicides with alternative modes of action in a short space of time seems very limited, suggesting the need for a more appropriate use of the available alternative strategies (crop rotation, dry sowing, manual weeding, etc.). This work presents a review of the main characteristics of rice cultivation in Spain, emphasizing the current problems in this crop and the management of herbicide-resistant weeds.
Purpose To assess 1) the cumulative greenhouse gas emissions –GHG- and global warming potential (methane – CH4- and nitrous oxide) from rice fields in the growing and fallow seasons, and 2) the environmental and agronomic drivers of CH4 emissions, and their relative capacity to explain CH4 variation. Methods A two-year multisite field experiment covering the agronomic and environmental variability of a rice growing area in NE Iberian Peninsula was conducted with monthly samplings of GHG and monitoring of both environmental and agronomic factors. Information-theoretic framework analysis was used to assess the relative contribution of the environmental and agronomic variables on methane emissions. Results Two thirds of the CH4 is emitted in the fallow season. Edaphic factors exert more influence during the growing season whereas agronomic factors have a higher impact in the fallow. The implications of these findings on the design of improved mitigation options rice are discussed. Conclusions Soils with higher soil sulphate concentration, bulk density and clay content emit less CH4 in growing season. In the fallow season, the rates of both straw input and nitrogen fertilization stimulate CH4 emissions. Graphical abstract
Wheat and rice are two main staple food crops that may suffer from yield losses due to drought episodes that are increasingly impacted by climate change, in addition to new epidemic outbreaks. Sustainable intensification of production will rely on several strategies, such as efficient use of water and variety improvement. This review updates the latest findings regarding complementary approaches in agronomy, genetics, and phenomics to cope with climate change challenges. The agronomic approach focuses on a case study examining alternative rice water management practices, with their impact on greenhouse gas emissions and biodiversity for ecosystem services. The genetic approach reviews in depth the latest technologies to achieve fungal disease resistance, as well as the use of landraces to increase the genetic diversity of new varieties. The phenomics approach explores recent advances in high-throughput remote sensing technologies useful in detecting both biotic and abiotic stress effects on breeding programs. The complementary nature of all these technologies indicates that only interdisciplinary work will ensure significant steps towards a more sustainable agriculture under future climate change scenarios.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.