Weedy rice is a conspecific weed of cultivated rice oryza sativa l. Identification of novel qtl conferring sheath blight. Weedy rice, however, has emerged as a serious threat to rice production in countries malaysia, sri lanka, thailand, vietnam, the. Weedy rice is characterized as genetically diverse populations of oryza spp. Forwardlooking in its approach, the work also assesses the areas of future research necessary to defeat these agricultural pests. Sep 01, 2019 weedy crop relatives are among the worlds most problematic agricultural weeds, and their ability to rapidly evolve can be enhanced by gene flow from both domesticated crop varieties and wild crop progenitor species. Molecular plant vol 12, issue 5, pages 603726 6 may. University of california rice online weedy rice workshops. In this study, we assessed cold tolerance of 100 rice varieties and 100 co. Red rice also shows high morphological and phenological diversity, which affects its response to imposed management practices.
Origins of weedy rice revealed by polymorphisms of. Foley abstract such as rice to weedy or red rice oryza spp. Despite the wealth of candidate genes that have been identified, the extent of phenotypic contributions to resistance has not been determined. Rice sheath blight shb disease, caused by the pathogenic fungus rhizoctonia solani, causes significant yield losses globally. They possess red pericarp and shed their grains easily. Competitive n uptake between rice and weedy rice sciencedirect. The shift in the method of establishing rice, that is, from transplanting to direct seeding, is considered the main reason for the emergence of weedy rice in asia and, more recently, japan. Overviewofweedyredrice oneof,ifnotthe,worstweedsinrice throughoutmostricegrowingregions oftheworld.
The first reference to weedy rice in the literature was reported by biroli in 1807 grimm 2014 and its occurrence in the usa was reported in 1898 chen and suh 2015. Seed dormancy imposed by covering tissues interrelates to. The us ranks third among riceexporting nations childs 2005 and us rice production is among the most efficient in the world moldenhauer et al. The name weedy rice is used for all types and variations of rice which show some characteristic features of cultivated rice and grow as weeds in commercial rice fields. Tilling the soil prior to crop planting should stimulate the. Management strategies for international rice research institute. Management strategies for weedy rice in asia books international. The persistence of weedy rice has been attributed, in part, to its ability to shatter disperse seed prior to crop harvesting. Introduction of imidazolinone herbicide and clearfield. Sep 30, 2017 weedy rice refers to the unwanted plants of the genus oryza that have some undesirable agronomic traits and pose a major threat to sustainable rice production worldwide. Weedy rice is conspecific, the most troublesome weed of cultivated rice identified as a threat to global rice production. Genomic variation associated with local adaptation of. We mapped quantitative trait loci qtl associated with shb resistance using two f8 recombinant inbred. In this study, we examined the role of modern commercial crop cultivars, traditional landraces, and wild relatives in the recent emergence and proliferation of weedy rice in.
Root system architecture rsa is a critical aspect of plant growth and competitive ability. Oryza rufipogon was collected as vegetative stocks from chaling in hunan province in china, and its. Information on the occurrence of weedy rice during the past 16 years was obtained by field investigations and. Incidences of weedy rice continuously occurred in paddy fields because its shattering seeds were able to overwinter. Red rice weedy rice is a major weed problem in rice production in the southern u. To prevent overcrowding the rice with weedy rice plants, onehalf of the weedy rice seed was heatkilled and at the one to twoleaf stage, weedy rice. This project will evaluate the extent of morphological. As the weedy relative of a genomic model species, red rice is supremely suited to serve as a model for understanding the processes by which weediness emerges in. In this research, the seed deterioration of weedy rice was investigated compared with cultivated rice, and the wintering characteristics of these two types of rice were investigated with the field wintering test, freezing resistance test, and accelerated aging test.
Of 1800 species reported as weeds of rice, those of the cyperaceae and poaceae are predominant. An emerging threat for directseeded rice production. Distribution of weedy rice escape variants in clearfield rice production system article pdf available in research on crops 154. Weedy rice is variable in height, panicle form, grain size, awn length, flag leaf, and growth duration. Biology and management of barnyardgrass, red sprangletop. Land preparation and manual weeding are typical methods for weedy rice control. After 1960, the occurrence and infestation rate of weedy. Aug 09, 2017 university of california rice online weedy rice workshops. May 06, 2019 volume 12, issue 5 pages 603726 6 may 2019. Introduction of imidazolinone herbicide and clearfield rice.
Weedy rice oryza sativa was used as a model to address the similarity of sd genes between distinct ecotypes. Jun 02, 2018 introduction of imidazolinone herbicide and clearfield rice between weedy ricecontrol efficiency and environmental concerns. Weeds can also make it difficult to harvest the crop, and seeds of some species can contaminate the grain and reduce its quality and price. One accession of the perennial wild rice oryza rufipogon, accessions of weedy rice o. Mar 23, 2020 rice sheath blight shb disease, caused by the pathogenic fungus rhizoctonia solani, causes significant yield losses globally. Weedy rice represents an emerging threat to transplanted rice. Diversity and ecophysiology of weedy rice red rice, oryza. Widespread adoption of direct seeded rice and hybridization or gene flow between cultivated rice and their wild relatives has resulted in the creation and dissemination of weedy rice. Rice drew and strawhull weedy rice were drillseeded at 90 kg ha 1, onmay 7, 1999 and may 1,2000, in alternate rows, 19 cm apart, 2. Management strategies for international rice research.
Weedy rice is often but not exclusively associated with a red pericarp and can be referred to as red rice. Feral rice from introgression of weedy rice genes into. Although a range of weed species is encountered in countries where dsr is already practiced e. Our discussion of weedy rice in the present paper focuses on the latter situation, and specifically on the weedy rice found in us rice fields. Seed dormancy imposed by covering tissues interrelates to shattering and seed morphological characteristics in weedy rice xingyou gu, shahryar f. Competitive ability, evolution, and diversity intechopen. Signatures of adaptation in the weedy rice genome nature. Genetic diversity and origin of weedy rice oryza sativa f. Convergent evolution of root system architecture in two. Drew is a longgrain cultivar developed in arkansas, released in 1996, and was chosen because it was highyielding and widely planted in the southern. Weedy rice refers to the unwanted plants of the genus oryza that have some undesirable agronomic traits and pose a. This researchbased, scholarly work engenders a further understanding of weeds and invasive plants, opening avenues for. The weedy rice parents are representatives of the sh and bha populations of u. Weedy red rice has novel sources of resistance to biotic stress.
The authors report here a case of hybrid sterility between an indica cultivar, ir36 and a weedy strain, ludao, which naturally grows in and around farms in jiangsu province, china. Weedy rice is a serious problem of cultivated rice in most of the ricegrowing areas in asia, causing increased production costs and yield losses in rice. There were three replications per treatment, and rice than in cultivated rice oka, 1988, p. Nov 12, 2019 the mechanisms by which weedy rice oryza sativa f.
Mar 18, 2019 root system architecture rsa is a critical aspect of plant growth and competitive ability. A study was conducted to determine the response of weedy rice accessions from india iwr, malaysia mwr, thailand twr, and vietnam vwr to seed burial and flooding depths. Weedy rice is widely distributed all around the globe fig. Weedy and invasive plant genomics offers a comprehensive, uptodate reference on genetic and genomics research in weedy and invasive plants. The origin of weedy rice ludao in china deduced by genome. Weedy crop relatives are among the worlds most problematic agricultural weeds, and their ability to rapidly evolve can be enhanced by gene flow from both domesticated crop varieties and wild crop progenitor species. Agricultural weeds serve as productive models for studying the genetic basis of rapid adaptation, with weedadaptive. Mahyoub izzat bzour, a fathiah mohamed zuki, b muhamad shakirin mispan c. As the weedy relative of a genomic model species, red rice is supremely suited to serve as a model for understanding the processes by which weediness emerges in agricultural settings. B, c, experimental plots in which feral plants were found highlighted in red in 2012 b and in 20 c together with the number of feral individuals found in each plot underlined. For example, in adoption of dsr in south korea, weedy rice became the. We found that the studied weedy rice accessions evolved either from their wild or cultivated rice progenitor, as the maternal donor, based on the cpdna network and structure analyses. Genomic variation associated with local adaptation of weedy.
Weedy rice, which differs genetically from wild and crop. Weedy rice workshops university of california rice online. The course will include a handson weed identification session on emerging and mature weeds. Jun 11, 2018 weedy rice is a conspecific weed of cultivated rice oryza sativa l. A genomewide analysis was performed with a backcross population of ir36ludaoir36 using a total of 151 simple sequence repeat ssr markers covering the entire rice linkage map. The impact of herbicideresistant rice technology on phenotypic diversity and population structure of united states weedy rice. Weedy rice represents an emerging threat to transplanted. Occurrence and frequency of weedyricelike feral plants and their identification. A total of 12 quantitative trait loci qtl for sd were identified in one primary and two advanced backcross bc populations derived from a temperate ecotype of weedy. Genotypic variation at multiple loci for seed dormancy sd contributes to plant adaptation to diverse ecosystems. In korea, weedy rice was observed in 1916, where it was called sharebyeo by local farmers hara 1942. Weeds of upland crops in cambodia p1 weeds can be a problem in the production of upland crops because they reduce yield by competing for resources essential for growth, such as water, nutrients and light. Red rice is one of the most serious weed problems of rice cultivation worldwide fao 2007.
Weedy rice accompanies the cultivation of rice worlda whatman no. Download 743kb pdf rice weed course 2019 meeting reminder. The objectives of this study are to determine the genetic diversity and differentiation of weedy rice populations from liaoning province in northeastern china and to explore the possible origin of these weedy populations by comparing their genetic. They are commonly known as weedy red rice, or simply, red rice. What rice farmers say about weeds weeds is rank as 1st or 2nd problem in rice weed management in rice is challenging, complex, expensive, and regulated herbicide is the preferred method of controlling weed and it is the first and probably the last line of defense farmers are not quit sure if herbicides are working well. Occurrence and frequency of weedy rice like feral plants and their identification. Apr 03, 2017 weedy rice, which differs genetically from wild and crop rice, is adapted for undercover life in agricultural fields. Generally, seed dormancy is stronger in weedy sterile water. The greatest emergence for each weedy rice accession. New earth market, 1475 tharp road, yuba city, ca 95993 and. Get to know some unique recipes that use weeds as the main ingredient.
Weedy rice, also known as red rice, is a variety of rice that produces far fewer grains per plant than cultivated rice and is therefore considered a pest. Weedy rice cannot be grown at the same density as rice without a severe impediment in rice growth kwon et al. The experimental plot was designed as complete random blocks where nam29tr18 was planted with 35 hills per row, and mixed with one of the weedy rice accessions in each block. Cultivated rice fields worldwide are plagued with weedy rice, a conspecific weed of cultivated rice oryza sativa l. Red rice is an aggressive, weedy form of cultivated rice that infests crop fields and is a primary factor limiting rice productivity in the u.
Weedy rice, which differs genetically from wild and crop rice. Inheritance of seed dormancy in weedy rice gu 2003. Molecular plant vol 12, issue 5, pages 603726 6 may 2019. Gene flow from cultivated rice oryza sativa to its weedy. Initial investigations using intact seeds, caryopses, caryopses with pericarptesta removed, and excised embryos demonstrated that seed dormancy was imposed by the hull in. Weedy rice can be a serious problem because it is very competitive with cultivated rice, its seeds have dormancy, and its grains shatter easily. Combined analyses of cpdna and nuclear ssr markers demonstrated that a much greater proportion of weedy rice accessions had the endo. Management strategies for weedy rice in asia iii foreword rice is the principal source of food for more than half of the world population. In recent years, however, growers in many asian countries are.
In asia, it is commonly grown by manual transplanting of seedlings after tillage in wet conditions. Ecological genetics genomics of weedy rice by muhamad. Weedy rice, which differs genetically from wild and crop rice, is adapted for undercover life in agricultural fields. Us weedy rice populations, which are dedomesticated forms of indica and aus cultivated rice, appear to be more resistant to shb than local japonica cultivated rice. Pdf weedy rice refers to the unwanted plants of the genus oryza that have some undesirable agronomic traits and pose a major threat to. After an extensive survey of weedy rice infestation in all riceplanting areas of northeastern china, six regions in liaoning province were selected as sampling sites fig.