Density Dependent Competitive Interactions between Weedy Rice (Oryza Sativa F. Spontanea) and Cultivated Rice in Sri Lanka

Abstract Weedy rice (Oryza sativa L.) is one of the most troublesome weeds affecting rice (Oryza sativa L.) production in many countries. Weedy rice control is difficult in rice fields because the weed and crop are phenotypically and morphologically similar. Weedy rice can be a source of genetic diversity to cultivated rice. Thus, this study aimed to characterize the morphological diversity of weedy rice in Southern Brazil. Qualitative and quantitative traits of 249 accessions from eight rice growing mesoregions in Rio Grande do Sul (RS) and Santa Catarina (SC) states were analyzed. For each accession, 24 morphological descriptors (14 qualitative and 10 quantitative) were evaluated. All the 249 accessions from RS and SC are of indica lineage. Considering all the phenotypic traits evaluated, the accessions separated into 14 distinct groups. One of the largest groups consisted of plants that were predominantly tall and with green leaves, intermediate shattering, and variable in flowering time. Distinct subgroups exist within larger clusters, showing discernable phenotypic diversity within the main clusters. The variability in flowering time was high (77 to 110 d after emergence), indicating high potential for flowering synchrony with rice cultivars and, consequently, gene flow. This indicates the need to remove escapes when planting herbicide-resistant rice. Thus, weedy rice populations in Southern Brazil are highly diverse and this diversity could result in variable response to weed management.

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The impact of nano-ZnO foliar fertilizer on growth and yield of cultivated rice (Oryza sativa L.) varieties in Sri Lanka

Ceylon Journal of Science ◽

10.4038/cjs.v50i2.7872 ◽

2021 ◽

Vol 50 (2) ◽

pp. 109

Author(s):

S. Somaratne ◽

S. R. Weerakoon ◽

N. Karthikeyan ◽

D.S.P. Munasinghe

Keyword(s):

Oryza Sativa ◽

Sri Lanka ◽

Growth And Yield ◽

Cultivated Rice ◽

Nano Zno ◽

Foliar Fertilizer ◽

The Impact

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Natural Herbicide Resistance (HR) to Broad-spectrum Herbicide, Glyphosate among Traditional and Inbred-cultivated Rice (Oryza sativa L.) Varieties in Sri Lanka

Pakistan Journal of Biological Sciences ◽

10.3923/pjbs.2013.796.803 ◽

2013 ◽

Vol 16 (16) ◽

pp. 796-803 ◽

Cited By ~ 3

Author(s):

S.R. Weerakoon ◽

S. Somaratne ◽

R.G.D. Wijeratne ◽

E.M.S.I. Ekanyaka

Keyword(s):

Oryza Sativa ◽

Sri Lanka ◽

Herbicide Resistance ◽

Broad Spectrum ◽

Oryza Sativa L ◽

Cultivated Rice ◽

Natural Herbicide ◽

Herbicide Glyphosate

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Phenotypic diversity of weedy rice (Oryza sativa f. spontanea) biotypes found in California and implications for management

Weed Science ◽

10.1017/wsc.2020.43 ◽

2020 ◽

Vol 68 (5) ◽

pp. 485-495

Author(s):

Elizabeth Karn ◽

Teresa De Leon ◽

Luis Espino ◽

Kassim Al-Khatib ◽

Whitney Brim-DeForest

Keyword(s):

Oryza Sativa ◽

Chlorophyll Content ◽

Plant Height ◽

Wild Rice ◽

Early Growth ◽

Weedy Rice ◽

Phenotypic Traits ◽

Growth Stages ◽

Cultivated Rice ◽

Leaf Pubescence

AbstractWeedy rice (Oryza sativa f. spontanea Rosh.) is an emerging weed of California rice (Oryza sativa L.) that has potential to cause large yield losses. Early detection of weedy rice in the field is ideal to effectively control and prevent the spread of this weed. However, it is difficult to differentiate weedy rice from cultivated rice during early growth stages due to the close genetic and phenotypic relatedness of cultivated rice and weedy rice. The objective of this study is to examine phenotypic variation in weedy rice biotypes from California and to identify traits that could be used to visually identify weedy rice infestations at early growth stages for effective management. Greenhouse experiments were conducted in 2017 and 2018 using five phenotypically distinct biotypes of weedy rice found in California, along with diverse cultivated, weedy, and wild rice types in a randomized complete block design. We measured variation for 13 phenotypic traits associated with weedy rice and conducted principal component analysis and factor analysis to identify important weedy traits. Most weedy rice individuals within a biotype clustered together by phenotypic similarity. Pericarp color, hull color, chlorophyll content, grain length, plant height, leaf pubescence, collar color, and leaf sheath color account for most of the observed variation. California weedy rice biotypes are phenotypically distinct from wild rice and from weedy rice from the southern United States in their combinations of seed phenotypes and vegetative characteristics. In comparison with the locally grown temperate japonica cultivars, California weedy rice tends to be taller, with lower chlorophyll content and a red pericarp. Weedy rice biotypes vary in seed shattering and seed dormancy. For weedy rice management, plant height and chlorophyll content are distinct traits that could be used to differentiate weedy rice from the majority of cultivated rice varieties in California during vegetative stages of rice growth.

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Fine mapping of a gene causing hybrid pollen sterility between Yunnan weedy rice and cultivated rice (Oryza sativa L.) and phylogenetic analysis of Yunnan weedy rice

Planta ◽

10.1007/s00425-009-1063-7 ◽

2009 ◽

Vol 231 (3) ◽

pp. 559-570 ◽

Cited By ~ 10

Author(s):

Yong Wang ◽

Zheng Zheng Zhong ◽

Zhi Gang Zhao ◽

Ling Jiang ◽

Xiao Feng Bian ◽

...

Keyword(s):

Phylogenetic Analysis ◽

Oryza Sativa ◽

Fine Mapping ◽

Oryza Sativa L ◽

Pollen Sterility ◽

Weedy Rice ◽

Cultivated Rice

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Rapid PCD Process Promotes Early Maturity in Weedy Rice (Oryza sativa L. f. spontanea)

10.21203/rs.3.rs-75420/v1 ◽

2020 ◽

Author(s):

Can Zhao ◽

Wenrong Xu ◽

Zheng Zhang ◽

Lingchao Meng ◽

Weimin Dai ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Oryza Sativa ◽

Cell Viability ◽

Grain Filling ◽

Oxidative Enzymes ◽

Weedy Rice ◽

Oxygen Species ◽

Cultivated Rice ◽

Early Maturity ◽

Grain Filling Period

Abstract Background: Shorter grain-filling period and rapid endosperm development contributes to early maturity in weedy rice (Oryza sativa L. f. spontanea). However, the differences in programmed cell death (PCD) process and anti-oxidative enzymes system in the caryopsis between weedy and cultivated rice are largely unexplored. Main Text: we selected four biotypes of weedy rice and associated cultivated rice (ACR, Oryza sativa) from different latitudes to conduct a common garden experiment. The difference of PCD process between weedy rice and ACR was compared by chemical staining, and the cell viability and nuclear morphometry of endosperm cells were observed by optical microscopy, and anti-oxidative enzymes activity were also measured during grain filling. We found that the PCD progress in weedy rice was more rapid and earlier than that in ACR. The percentage of degraded nuclei of weedy rice were 10%-83% higher than that of ACR. Endosperm cells in weedy rice lost cell viability 2-8 days earlier than that in ACR. The anti-oxidant enzymes activity of weedy rice were lower than that of ACR during grain filling. The ability of weedy rice to scavenge reactive oxygen species is weaker than that of ACR, which may contribute to the rapid PCD process in the endosperm cells of weedy rice. Conclusion: The rapid PCD process and weaker ability to scavenge reactive oxygen species in endosperm cells lead to the shorter grain-filling period of weedy rice.

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Responses of Weedy Rice to Drought Stress at Germination and Seedling Stages

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.316-317.451 ◽

2013 ◽

Vol 316-317 ◽

pp. 451-459 ◽

Cited By ~ 4

Author(s):

Guo Hua Ding ◽

Xiao Liang Liu ◽

Dian Rong Ma ◽

Xiao Xue Wang ◽

Guang Yang ◽

...

Keyword(s):

Oryza Sativa ◽

Water Stress ◽

Drought Stress ◽

Root Length ◽

Dry Weight ◽

Shoot Length ◽

Stress Index ◽

Weedy Rice ◽

Fresh Weight ◽

Cultivated Rice

Drought is a world-spread problem seriously influencing grain production and quality, the loss of which is the total for other natural disasters, with increasing global climate change making the situation more serious. Rice is the staple food for more than 23% of world population, so rice anti-drought physiology study is of importance to rice production and biological breeding for the sake of coping with abiotic and biotic conditions. Much research is involved in this hot topic, but the pace of progress is not so large because of drought resistance being a multiple-gene-control quantitative character. On the other hand, stress adaptive mechanisms are quite different, with stress degree, time course, materials, soil quality status and experimental plots, thus increasing the complexity of the issue in question. Additionally, a little study is related to weedy rice.In order to investigate the effects of drought stress on germination and early seedling growth of weedy rice (Oryza sativa f. spontanea L.) and cultivated rice (Oryza sativa L.), polyethyleneglycol-6000 (PEG-6000) are used to generate -1.33MPa and 0MPa water stress in a laboratory condition (28±3°C). Complete randomized design with three replications is used in the study. After 10 days of germination, shoot length, the longest root length, root fresh weight, root dry weight, shoot fresh weight, shoot dry weight and root numbers are measured; germination percentage, and root to shoot ratio are calculated. Germination index (GI), shoot length stress index (SLSI), root length stress index (RLSI) and dry matter stress index (DMSI) are used to evaluate the response of different genotypes to PEG-induced water stress. Results of ANOVA analysis show that responses of weedy rice accessions and cultivated rice varieties to water stress are significant different, demonstrating the germplasm of weedy rice and cultivated rice are diverse which enables us to screen the germplasm tolerant to drought stress.

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Flooding depths and burial effects on seedling emergence of five California weedy rice (Oryza sativa spontanea) accessions

Weed Science ◽

10.1017/wsc.2021.82 ◽

2022 ◽

pp. 1-22

Author(s):

Liberty B. Galvin ◽

Deniz Inci ◽

Mohsen Mesgaran ◽

Whitney Brim-DeForest ◽

Kassim Al-Khatib

Keyword(s):

Oryza Sativa ◽

Seedling Emergence ◽

Weedy Rice ◽

Burial Depth ◽

Growth Responses ◽

Cultivated Rice ◽

Soil Burial ◽

Comparison Results ◽

Significant Difference ◽

Flooding Depth

Abstract Weedy rice (Oryza sativa f. spontanea Roshev.) has recently become a significant botanical pest in California rice (Oryza sativa L.) production systems. The conspecificity of this pest with cultivated rice, Oryza sativa (L.), negates the use of selective herbicides, rendering the development of non-chemical methods a necessary component of creating management strategies for this weed. Experiments were conducted to determine the emergence and early growth responses of O. sativa spontanea to flooding soil and burial conditions. Treatment combinations of four flooding depths (0, 5, 10, and 15 cm) and four burial depths (1.3, 2.5, 5, and 10 cm) were applied to test the emergence of five O. sativa spontanea accessions as well as ‘M-206’, a commonly used rice cultivar in California, for comparison. Results revealed that burial depth had a significant effect on seedling emergence. There was a 43-91% decrease in emergence between seedlings buried at 1.3 and 2.5 cm depending on the flooding depth and accession, and an absence of emergence from seedlings buried at or below 5 cm. Flooding depth did not affect emergence, but there was a significant interaction between burial and flooding treatments. There was no significant difference between total O. sativa spontanea emergence from the soil and water surfaces regardless of burial or flooding depths, implying that once the various accessions have emerged from the soil they will also emerge from the floodwater. Most accessions had similar total emergence compared to M-206 cultivated rice, but produced more dry weight than M-206 when planted at 1.3 cm in the soil. The results of this experiment can be used to inform stakeholders of the flooding conditions necessary as well as soil burial depths that will promote or inhibit the emergence of California O. sativa spontanea accessions from the weed seedbank.

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