Resistance Versus Susceptibility To Verticillium Albo-Atrum In Alfalfa,
2024
The Pennsylvania State University
Resistance Versus Susceptibility To Verticillium Albo-Atrum In Alfalfa, B W. Pennypacker, K T. Leath, D P. Knievel, E J. Pell
IGC Proceedings (1977-2023)
Alfalfn (Medicago saliva L.) clones, susceptible and resistant to Verticillium albo-atrum (Van), were systematically infected with Vaa via stubble inoculation with conidial suspensions. Progress of infection and anatomical host responses was monitored by sequential sampling, sectioning, staining and examination with light microscopy. Effect of infection on photosynthesis was assessed in vivo by measuring net photosynthesis and activity of ribulose 1, 5-biphosphate carboxylaseoxygenase (rubisco) via a CO2 drawdown curve. hr vitro activity of rubisco was determined by protein extraction and uptake of radioactive CO2. Susceptible and resistant clones exhibited leaflet chlorosis and abscission. Also, the pathogen produced spores that germinated …
Breeding For Multiple Pest Resistance As A Strategy To Improve White Clover Persistence,
2024
USDA, Agricultural Research Service
Breeding For Multiple Pest Resistance As A Strategy To Improve White Clover Persistence, G A. Pederson, G L. Windham, M R. Mclaughlin, R G. Pratt, G E. Brink
IGC Proceedings (1977-2023)
White clover (Trifolium repens L.) cultivars grown in the USA are susceptible to many pathogens, pests and environmental stresses which have been shown to affect persistence adversely. The strategy used in our breeding programme is to first develop white clover populations resistant to individual pathogens and pests, and then incorporate this resistance into multiple-pest-resistant populations. Germplasms with resistance to peanut stunt virus (PSV), alfalfa mosaic virus (AMY), and clover yellow vein virus (CYVV), and with drought tolerance have been released. From these germplasms and other source materials, we have developed additional populations with resistance to southern root-knot nematode ( …
Clover Cyst Nematode Resistance In White Clover,
2024
AgResearch, NZ
Clover Cyst Nematode Resistance In White Clover, J Van Bosch, C F. Mercer, J L. Grant, I K. Black
IGC Proceedings (1977-2023)
White clover (Trifolium repens L.), a key legume in New Zealand pastures, is parasitised by Heterodera trifolii, the clover cyst nematode. Resistance breeding is the most feasible control, and screening of 1st generation crosses has made considerable progress. Progeny of parents selected for resistance had only 39% cysts/g root dry weight of susceptible lines, and all resistant lines were lower when ranked. These resistant selections also had less fewer cysts per plant, heavier root dry weights and higher shoot growth scores. The parents of the most resistant lines were from two Italian ladino cultivars (Ladino Gigante Lodigiano and …
Rhoma Black Stem Disease- A Threat To Susceptible Annual Medic Pastures,
2024
Department of Agriculture, AU
Rhoma Black Stem Disease- A Threat To Susceptible Annual Medic Pastures, M J. Barbetti
IGC Proceedings (1977-2023)
Phoma black stem disease, caused by Phoma medicaginis, is the most important fungal disease of annual Medicago spp. (medic) pastures in Western Australia. It is readily seed-borne and this provides an important inoculum source for spreading the disease into new sowings in areas free of leguminous crop residues. The disease produces dark brown to black lesions on cotyledons, leaves, petioles and stems and can cause leaf drop and petiole and stem collapse, Reductions in herbage production of up to 169!, and seed yield of up to 209!, have been recorded in grazed swards, while in ungrued swards, losses in herbage …
Effectiveness Of Acremoniu Lolli In Annual Ryegrass In Controlling Greenbug (Schizaphis Graminum Rondani) Injury,
2024
Texas A&M
Effectiveness Of Acremoniu Lolli In Annual Ryegrass In Controlling Greenbug (Schizaphis Graminum Rondani) Injury, L R. Nelson, Marta R. Harrington, D Marshall
IGC Proceedings (1977-2023)
This experiment tested 3 ryegrass (Lolium multiflorum Lam.) genotypes with (E+ )° and without (E-) endophyte, to determine the effectiveness of the endophyte in reducing leaf damage caused by greenbugs (Schlzaplris granthum Rondani). Results Indicated that presence of endophyte increased resistance in only I of 3 lines tested. The apparent resistance was observed.as leaf necrosis (leaf necking, yellowing, tip die-back, and leaf death). Resistance was not observed until green bug reinfestation of 3-month-old plants. A control with E+ Kentucky 31 fescue (Festuca arundinacea Schreb.) also had reduced greenbug damage compared with E- Kentucky 31 plants. This study …
Invertebrate Pests Of Endophyte-Infected And Endophyte Free Perennial Ryegrass Swards In Northern New Zealand,
2024
AgResearch, NZ
Invertebrate Pests Of Endophyte-Infected And Endophyte Free Perennial Ryegrass Swards In Northern New Zealand, R A. Prestidge, R N. Watson, E R. Thom
IGC Proceedings (1977-2023)
Plots of endophyte-infected and endophyte-free perennial ryegrass (Lollum perenne) cv. Ellett and white clover (Trifolium repens) cv, Grasslands Pitau were established in autumn 1990 by direct drilling into pastures previously sprayed with glyphosate herbicide. Plots were rotationally grazed by dairy cows. Insect pests were sampled by soil coring and extraction, and plant pathogenic nematodes by root staining and examination. Ryegrass tiller density and the proportion of ryegrass in the swards were-significantly less in November, March and May on plots sown with endophyte-free ryegrass c_ompared with endophyte-infected ryegrass. Conversely, the propo!'tion __ of white clover was greater on endophyte-free …
Invertebrate Pests Associated With Italian Ryegrass In Northern New Zealand,
2024
AgResearch, NZ
Invertebrate Pests Associated With Italian Ryegrass In Northern New Zealand, R A. Prestidge, R N. Watson, E R. Thom
IGC Proceedings (1977-2023)
Damage threshold levels were established for adult Argentine stem weevil (Listronotus bonariensis (Kuschel)) feeding on Italian ryegrass (Lolium multiflorum Lam;) cv, Concord seedlings in a glasshouse pot trial. Population densities of 35-70/m1 reduced seedling survival by 34% and herbage yield after 28 days growth by 35%. A field trial was established In autumn 1991 by sowing Concord in early February, in late February and in March into areas previously treated with glyphosate herbicide, Insecticide application increased ryegrass tiller density by 36% from 2339/m' (April 1991) and herbage accumulation by 43% from 1.4 t DM/ha only up to the …
Screening For Biological Control Agents Of Root Pathogens Of Pasture Legumes,
2024
AgResearch, NZ
Screening For Biological Control Agents Of Root Pathogens Of Pasture Legumes, R A. Skipp, F S. Hay
IGC Proceedings (1977-2023)
Fungi isolated from roots of legumes from pasture soil were applied to seeds of red clover (Trifolium pratense L.) on water agar in Petri plates in a seedling screening test designed to detect antagonism to the fungal pathogens Fusarium solani, Trichrocadium basicola and a Pythium sp. Isolates of Triclroderma koningii, T. /ramatum, a binucleate Rhizoc1011ia sp. or an unidentified basidiomycete protected seedling roots from damage by one or more of the fungal pathogens. Fungi isolated from cysts of the plant-parasitic nematode Helerodera trifolii obtained from pasture soil were tested for their ability to infect eggs of H. trifolii …
Effects Of Three Viruses On Productivity Of Annual Pasture Legume Swards,
2024
Department of Agriculture
Effects Of Three Viruses On Productivity Of Annual Pasture Legume Swards, R A. C Jones
IGC Proceedings (1977-2023)
The effects of 3 non-persistently aphid-transmitted viruses on the productivity of swards of annual pasture legumes were investigated in 1988-91. Virus-host combinations studied were alfalfa mosaic virus (AMV) in burr medic (Medicago polymorplia), cucumber mosaic virus (CMV) in subterranean clover (Trifo/i111n subterra11eum) and bean yellow mosaic virus (BYMV) in subterranean clover. Swards were mown to simulate grazing, grazed or left undefoliated. Herbage (dry weight) and seed production were decreased significantly by infection with all three virus-host combinations. However, the extent of losses vnried with extent of virus spread, cultivar, site and season. Decreased seed yield resulted from both fewer and …
Burial Of Surface-Applied Lime By Earthworms In South Australian Pastures,
2024
CSIRO
Burial Of Surface-Applied Lime By Earthworms In South Australian Pastures, G H. Baker, P. M.L Williams, V J. Barrett, P J. Carter
IGC Proceedings (1977-2023)
The ability of earthworms, Aporrectodea trapewides, A. caliginosa, A. rosea (Lumbricidae) and Gemascolex walkeri (Megascolecidae), to bury surface-applied lime and offset soil acidity was investigated in 2 pastures in the Mount Lofty Ranges, South Australia, In one pasture, A. trapewides increased pH by 0.8 of a unit at 4-6 cm depth. A. caliginosa also increased soil pH compared with controls, but A. rosea and G. walkeri had no influence, A. trapewides is suggested as a valuable addition to acid pastures, if not already present,
Effects Of Fungicide Seed Treatments On Germination And Establishment Of Sainfoin And Other Legumes,
2024
Gansu Grassland Ecological Research Institute
Effects Of Fungicide Seed Treatments On Germination And Establishment Of Sainfoin And Other Legumes, Nan Zhi Biao, Liu Zhao Hui, R A. Skipp
IGC Proceedings (1977-2023)
Treatment of seed with thiram or thiophanate methyl at a rate of 3 g ai/kg seed increased germination of crownvetch (Coro11illa varia L.), milkvetch (Astragalus ads11rge11s Pall.), sainfoin (011obrycl1is viciifolia Scop.) and yellow sweet clover (Melilotus officinalis (L.) Lam.) in laboratory tests. The magnitude of the increases varied with fungicide and species. The greatest increase in germination relativ!) to that of untreated seed was 115% for sainfoin dusted with thiophanate methyl. Thiophanate methyl increased field emergence of sainfoin at 4 and 8 weeks after sowing by 41% and 55% respectively, and at 8 weeks increased the dry weights of shoots …
Pastures In Crop Rotations Enhance Earthworm Populations In Southern Australia,
2024
CSIRO
Pastures In Crop Rotations Enhance Earthworm Populations In Southern Australia, John C. Buckerfield
IGC Proceedings (1977-2023)
The effects of crop rotations on earthworm populations in seasonally dry arable lands was assessed on long-term field trials at 2 sites with an annual rainfall of 450-500 mm, In cropping and sheep-grazing areas of southern Australia. Earthworm densities were substantially higher in rotations of cereals with a volunteer-pasture phase than under continuous cropping with cereals and grain legumes. The degree and frequency of soil disturbance associated with cropping has been shown to influence earthworm numbers: trial plots In which crops were sown with minimal cultivation, in alternate years, supported earthworm populations 2-3 times higher than those conventionally cultivated and …
Costs And Benefits Of Controlling Grasshoppers On Rangeland,
2024
New Mexico State University
Costs And Benefits Of Controlling Grasshoppers On Rangeland, E W. Huddleston, R Sanderson, L A. Torell, J H. Davis, J G. Watts
IGC Proceedings (1977-2023)
Ultra low volume (ULV) aerial application of malathion at 0.58 I/ha is the common method of rangeland grasshopper control in the USA. Aircraft often are unavailable or too expensive for treating small infestations; therefore, air-assist ground equipment was adjusted 10 apply the ULV rate from a small truck. In winds of 2.2 m/sec or greater, control with the ground equipment was equivalent to that expected from aircraft. The low spray volume, low sprayer cost and use of a small truck have increased the benefit/cost ratio. Using results from this research and site-specific estimates of control costs and forage value, the …
The Rodent Pests Of Pasture And Their Control In China,
2024
Chinese Academy of Agricultural Sciences
The Rodent Pests Of Pasture And Their Control In China, Xixian Hou, Weihui Dong, Yanlin Zhou
IGC Proceedings (1977-2023)
Rodent damage is increasingly recognised as a major problem for grasslands of China rodents damage up to an estimated 33 million ha each year, There are two reasons for rodent damage in grassland: one is overgrazing, which causes degeneration of grassland and provides good habitats for rodents; another is the ecological characteristics of rodents. A rodent control programme has been followed for years in China, and includes: (1) studies on the ecology of major rodent pests in pasture, (2) prediction of population, (3) setting up control indexes paying attention to economic benefits, (4) tightening up grassland management and developing integrated …
Stylo Host Heterogeneity For Anthracnose Management,
2024
CSIRO
Stylo Host Heterogeneity For Anthracnose Management, S Chakraborty, A N. Petitt, R M. Boland, S Low Choy, D F. Cameron, J A.G Irwin, R D. Davis
IGC Proceedings (1977-2023)
Small plots of 3 different mixtures of Stylosallllles. scabra genotypes were established within background paddocks of either pure cv. Seca, or a mixture of 6 S. scabra genotypes including Seca, to study anthracnose development in the three mixtures under exogenous inoculum pressures arising from the two backgrounds. There was no difference in disease severity between the background paddocks after the first year. In the small plots, severity of nearest neighbours significantly influenced anthracnose severity on the partially resistant accession 55860 in the first year; this effect disappeared as the disease became more widespread throughout the plot in later years. Replacing …
Increased Resistance To Sclerotinia Crown And Stem Rot Of Alfalfa Through Recurrent Selection Of Surviving Plants In Inoculated Field Plots, M Kanbe, F Fujimoto, S Inami
IGC Proceedings (1977-2023)
ABSTRACT Breeding alfalfa (Medicago saliva L.) for resistance to Sclerotinia crown and stem rot (SCR; causal agent Sclerotitivia trifoliorum Eriks.), which is a serious disease in Japan, was started in 1983. Increased resistance to this disease has been examined after repeated selected of surviving plants from artificially inoculated field plots to the 5th generation. The strains selected for SCR resistance showed higher resistance than Tachiwakaba, which was the main breeding material. The effectiveness of selection judged by the survival rate of progenies was low in the early selection generations but high in the later ones, It is considered that …
Biological Control Of Alfalfa Aphids In Japan Using Coccinella Septempunctata Brucki,
2024
National Grassland Research Institute
Biological Control Of Alfalfa Aphids In Japan Using Coccinella Septempunctata Brucki, Keiichi Takashi
IGC Proceedings (1977-2023)
The oviposition, predation, and survival abilities of Coccinella septempuncrara bmcki Mulsanl (lady beetle), a natural enemy of alfalfa aphids (Acyrtllosyphon kondoi Shinji), increased as temperatures rose in laboratory tests. The second-instar larvae were released into cages in alfalfa (Medicago saliva L.) fields in spring 1991. One month later, alfalfa plants in the control cages without larvae showed much lower yield; however, no damage was observed in cages in which larvae had been released. There is a strong probability that alfalfa aphids can be controlled by the timely release of lady beetle larvae in the field.
Twas Facilitates Gene-Scale Trait Genetic
Dissection Through Gene Expression, Structural
Variations, And Alternative Splicing In Soybean,
2024
Chinese Academy of Agricultural Sciences, Northeast Agricultural University
Twas Facilitates Gene-Scale Trait Genetic Dissection Through Gene Expression, Structural Variations, And Alternative Splicing In Soybean, Delin Li, Qi Wang, Yu Tian, Xiangguang Lyv, Hao Zhang, Huilong Hong, Huawei Gao, Yan-Fei Li, Chaosen Zhao, Jiajun Wang, Ruizhen Wang, Jinliang Yang, Bin Liu, Patrick S. Schnable, James C. Schnable, Ying-Hui Li, Li-Juan Qiu
Department of Agronomy and Horticulture: Faculty Publications
A genome-wide association study (GWAS) identifies trait-associated loci, but identifying the causal genes can be a bottleneck, due in part to slow decay of linkage disequilibrium (LD). A transcriptome-wide association study (TWAS) addresses this issue by identifying gene expression–phenotype associations or integrating gene expression quantitative trait loci with GWAS results. Here, we used self-pollinated soybean (Glycine max [L.] Merr.) as a model to evaluate the application of TWAS to the genetic dissection of traits in plant species with slow LD decay. We generated RNA sequencing data for a soybean diversity panel and identified the genetic expression regulation of 29 …
Significance Of Honeybee Pollination In Increasing Seed Yield Of Trifolium Alexandrinum (Fabales: Fabaceae) And Its Impact On Economic Sustainability Of Smallholder Farmers,
2024
Department of Primary Industries and Regional Development, Western Australia
Significance Of Honeybee Pollination In Increasing Seed Yield Of Trifolium Alexandrinum (Fabales: Fabaceae) And Its Impact On Economic Sustainability Of Smallholder Farmers, Muhammad Shoaib Tufail, Gaye L. Krebs, Alison Southwell, John Piltz, Peter C. Wynn, David F. Cook
Grain and Other Field Crops Research Articles
A major limitation to producing high seed yields in berseem clover (Trifolium alexandrinum L.) is failure to set seed, predominantly due to lack of pollination. Despite the importance of berseem clover as a leading forage legume, the contribution of pollinators to seed set is scarce. In Pakistan, the honeybee population is declining mainly because of the extensive use of neonicotinoid pesticides and habitat fragmentation. This, combined with the region’s harsh environment and the use of inferior, locally bred genotypes, has resulted in low seed yields. Insufficient seed availability leads to limited forage supply, resulting in poor livestock nutrition, which …
Genetic Diversity Of Soybean Dwarf Virus In Two Regions Of Mainland Australia,
2024
Department of Primary Industries and Regional Development, Western Australia
Genetic Diversity Of Soybean Dwarf Virus In Two Regions Of Mainland Australia, Benjamin S. Congdon, Murray Sharman, Monica Kehoe
Biosecurity Research Articles
Soybean dwarf virus (SbDV; family Tombusviridae, genus Luteovirus, species Luteovirus glycinis) is an RNA plant virus that is transmitted solely by aphids in a persistent, circulative and non-propagative manner. SbDV causes significant losses in cultivated Fabaceae, especially in subterranean clover (Trifolium subterraneum) pastures of mainland Australia. SbDV isolates are classified into four phenotypically distinguishable strains: YP, YS, DP, and DS. Y and D strains differ primarily in their host range, and P and S strains in their primary vector species. Genetically, Y and D strains separate into two clades in every genomic region except for …
