The relationship among 80 different Echinochloa accessions were studied in 2000–2002 by applying amplified fragment length polymorphism (AFLP) analysis and examining the main morphological traits of these plants. The plants were collected from 40 different areas in which the main rice-growing region of northern Italy was divided on the basis of uniform environmental and agronomical conditions. Echinochloa accessions were grouped in three different species (E. crus-galli, E. erecta, E. phyllopogon) according to Pignatti's classification key and in four different species according to Carretero's taxonomy (E. crus-galli, E. hispidula, E. oryzicola, and E. oryzoides). The E. crus-galli accessions clustered as a specific group under both AFLP analysis and morphological traits analysis carried out according to Pignatti's and Carretero's keys. AFLP analysis revealed a separate group containing two accessions with a green basal stem section. These were classified as E. crus-galli by Pignatti's taxonomy and E. oryzoides according to Carretero's taxonomy. A red basal stem section, a trait not considered by either morphological classification, was the main morphological trait that characterizes all E. crus-galli accessions. All other accessions with green basal stem section clustered in a group that included E. erecta and E. phyllopogon according to Pignatti's taxonomy and E. hispidula and E. oryzicola according to Carretero's taxonomy. All species were evenly distributed in the monitored rice area, except the two E. oryzoides accessions, which were found only in the southwestern zone.

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Weedy rice is one of the most damaging global weeds and a major threat to DSR systems. In this study we have developed a proof-of-concept method to allow selective weedy rice control in rice crops. We call for herbicide discovery programmes and research to identify candidate safener and herbicide combinations to achieve selective herbicide control of weedy rice and alleviate weed infestations in global rice crops. © 2016 Society of Chemical Industry.

International audienceRice (Oryza sativa L.) is the premier food crop in the world, being a major staple food for more than half of the world’s population. The potential for a further increase in grain yield will be limited in the future, and more food will need to be produced from the same available arable land. Italy has a long history of rice cultivation, but is now facing challenges to develop new strategies to maintain competitiveness of this sector in the global market. To prepare for the inevitable reduction of both rice prices and incentives from the European Community, and market protection, growers are evaluating the potential of hybrid rice cultivation to increase yields and maintain high quality standards for milling industries. Here we reviewed the characteristics of the Italian rice sector and the first experiences of hybrid cultivation in north Italy during 2012, using them to project the potential challenges and opportunities for both breeders and rice growers. If well managed this technology can represent a solution for sustainable rice production in Italy and in the other European rice growing countries. With hybrid vigor increased yield are obtained from reduced seed rate, lower nitrogen fertilizer, lower reliance on chemical treatments to control diseases, which helps compensate for the increased seed costs. Moreover, partially in contrast with current beliefs, it is shown that it may be possible to produce rice in rather rich countries obtaining a local production

Weed control in rice fields has become particularly difficult because of the increased occurrence of herbicide resistance. The objective of the study was to assess in field conditions, in Italy, if repeated applications of the same herbicides on Echinochloa spp. populations already showing an initial level of resistance would increase their level of resistance over a short time. Repeated applications of penoxsulam and cyhalofop-butyl were performed at different rates, either alone, in combination, or in sequence for one, two or three consecutive years (2010)(2011)(2012) in the same plots. Confirmation of resistance was performed in greenhouse on plants derived from untreated plots and from those that survived the field treatments. Penoxsulam efficacy was lower than that obtained with cyhalofop-butyl. The average efficacy across herbicide treatments declined over time as it was 52%, 32%, and 13% at 28 days after treatments in plots treated for one, two and three years, respectively. The treatments performed in greenhouse confirmed the low herbicide efficacy observed in the field. Study results highlighted that repeated applications of ALS and ACCase inhibitor herbicides can accelerate resistance selection in Echinochloa, and even herbicide rotation, sequencing, or mixing might not be effective if applied at time intervals of insufficient length.