The development of lucerne with resistance to root rot in poorly aerated soils

1978 ◽  
Vol 18 (92) ◽  
pp. 434 ◽  
Author(s):  
VE Rogers ◽  
JAG Irwin ◽  
G Stovold
Keyword(s):  
Root Rot ◽  
New South ◽  
New South Wales ◽  
Mass Selection ◽  
Infested Soil ◽  
Yield Data ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
South Wales ◽  
Disease Free

Three cycles of recurrent mass selection in the field increased the level of resistance of lucerne (Medicago sativa) to Phytophthora root rot in irrigated heavy clay soil at Deniliquin, New South Wales. The breeding stocks were derived from Siro Peruvian and Lahontan. In each cycle between 45 and 80 vigorous, disease free plants were selected from soil naturally infested with Phytophthora megasperma var. sojae, and allowed to interpollinate. Yield data and ratings for root rot were obtained for half-sib families sown in rows. Progeny in cycle 1 were inoculated by isolates of P. megasperma from both New South Wales and Queensland, and there was substantial agreement between both sources in ratings for disease. In the third cycle of selection, progeny had a disease rating of 1.4 when inoculated with Queensland isolates of P. megasperma, compared with 3.6 and 4.1 for Hunter River and Siro Peruvian respectively (plants scored 1 or 2 considered resistant; 3, 4 or 5 susceptible). In a field trial, the percentage of disease-free plants after eight months of growth in infested soil was: cycle 3 selections, 44.4; Hunter River, 9.9; Siro Peruvian, 12.0. Cumulative dry matter production of the selections during that time was twice that of Hunter River.

Occurrence of Phytophthora clandestina in Trifolium subterraneum paddocks in Australia

2001 ◽  
Vol 41 (2) ◽  
pp. 187 ◽  
Author(s):  
R. Aldaoud ◽  
W. Guppy ◽  
L. Callinan ◽  
S. F. Flett ◽  
K. A. Wratten ◽  
...  
Keyword(s):  
Western Australia ◽  
Root Rot ◽  
New South ◽  
New South Wales ◽  
South Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Soil Samples ◽  
South Wales ◽  
Differential Cultivars

In 1995–96, a survey of soil samples from subterranean clover (Trifolium subterraneum L.) paddocks was conducted across Victoria, South Australia, New South Wales and Western Australia, to determine the distribution and the prevalence of races of Phytophthora clandestina (as determined by the development of root rot on differential cultivars), and the association of its occurrence with paddock variables. In all states, there was a weak but significant association between P. clandestina detected in soil samples and subsequent root rot susceptibility of differential cultivars grown in these soil samples. Phytophthora clandestina was found in 38% of the sampled sites, with a significantly lower prevalence in South Australia (27%). There were significant positive associations between P. clandestina detection and increased soil salinity (Western Australia), early growth stages of subterranean clover (Victoria), mature subterranean clover (South Australia), recently sown subterranean clover (South Australia), paddocks with higher subterranean clover content (Victoria), where herbicides were not applied (South Australia), irrigation (New South Wales and Victoria), cattle grazing (South Australia and Victoria), early sampling dates (Victoria and New South Wales), sampling shortly after the autumn break or first irrigation (Victoria), shorter soil storage time (Victoria) and farmer’s perception of root rot being present (Victoria and New South Wales). Only 29% of P. clandestina isolates could be classified under the 5 known races. Some of the unknown races were virulent on cv. Seaton Park LF (most resistant) and others were avirulent on cv. Woogenellup (most susceptible). Race 1 was significantly less prevalent in South Australia than Victoria and race 0 was significantly less prevalent in New South Wales than in South Australia and Western Australia. This study revealed extremely wide variation in the virulence of P. clandestina. The potential importance of the results on programs to breed for resistance to root rot are discussed. in South Australia.

Simulation of the effect of chilling injury and nitrogen supply on floret fertility and yield in rice

1994 ◽  
Vol 34 (7) ◽  
pp. 921 ◽  
Author(s):  
DC Godwin ◽  
WS Meyer ◽  
U Singh
Keyword(s):  
Management Practices ◽  
New South ◽  
Chilling Injury ◽  
New South Wales ◽  
Growth And Yield ◽  
Comprehensive Model ◽  
Night Time ◽  
Yield Data ◽  
South Wales ◽  
High Yields

Evidence exists that night temperatures <18�C immediately preceding flowering in rice crops can adversely affect floret fertility and, hence, yields. It has been suggested that sterility induced by low temperature is also influenced by floodwater depth and nitrogen (N) rate. In southern New South Wales, low night-time temperatures are believed to be a major constraint to the achievement of consistently high yields. The availability of a comprehensive model of rice growth and yield that is sensitive to this constraint would aid the development of better management practices. CERES RICE is a comprehensive model that simulates the phasic development of a rice crop, the growth of its leaves, stems, roots, and panicles, and their response to weather. It also simulates the water and N balances of the crop and the effects of stresses of water and N on the yield-forming processes. The model has been extensively tested in many rice-growing systems in both tropical and temperate environments. However, the original model was unable to simulate the level of chilling injury evident from yield data from southern New South Wales. This paper reports modifications made in the model to simulate these effects and the evaluation of the model in environments of low night temperature. Inclusion of the chilling injury effect greatly improved the accuracy of estimated yields from treatments in an extensive field experiment. However, additional testing with a wider range of data sets is needed to confirm the international applicability of the modifications.

The prevalence and severity of diseases in the coastal soybean crop of New South Wales

1991 ◽  
Vol 31 (4) ◽  
pp. 545 ◽  
Author(s):  
GE Stovold ◽  
HJP Smith
Keyword(s):  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
New South ◽  
Soybean Mosaic Virus ◽  
New South Wales ◽  
Coastal Region ◽  
Leaf Blight ◽  
Stem Rot ◽  
Phytophthora Megasperma ◽  
South Wales

Rainfed soybean (Glycine max) crops in the northern coastal region of New South Wales were surveyed from 1985 to 1987 for the prevalence and severity of diseases. Sixteen diseases were recorded over the 3 seasons, but only rust (Phakopsora pachyrhizi), black leaf blight (Arkoola nigra) and bacterial pustule (Xanthomonas campestris pv. glycines) were present each season. Rust was the most significant disease, infecting 50, 20 and 6% of crops in 1985, 1986 and 1987. The severity of rust was related to rainfall and temperature after flowering, with the most severe outbreaks in the higher rainfall area of the lower Richmond Valley. Black leaf blight was also significant and occurred in 39, 10 and 27% of crops in 1985, 1986 and 1987, but in most crops severity was low. The other diseases recorded were downy mildew (Peronospora manschurica), root and stem rot (Phytophthora megasperma f. sp. glycinea), stem canker (Rhizoctonia sp.), pod and stem blight (Phomopsis spp.), anthracnose (Colletotrichum spp.), seedling blight (Rhizoctonia sp.), stem rot (Phytophthora sp.), white mould (Sclerotinia sclerotiorum), flower blight (Botrytis cinerea), leaf spot (Phoma sp.), bacterial blight (Pseudomonas syringae pv. glycinea), mosaic (soybean mosaic virus) and orange bark (not identified). All of these diseases were generally of low prevalence and severity.

Aphanomyces Root Rot of Bean at Valla, New South Wales.

1987 ◽  
Vol 16 (4) ◽  
pp. 82 ◽  
Author(s):  
RN Allen ◽  
DB Letham ◽  
AA Akehurst ◽  
MM Say
Keyword(s):  
Root Rot ◽  
New South ◽  
New South Wales ◽  
South Wales

Comparison of lucernes when grown on a heavy clay soil infected by Phytophthora, and their response to attack by the spotted alfalfa aphid (Therioaphis trifolii f. maculata)

1981 ◽  
Vol 21 (108) ◽  
pp. 63 ◽  
Author(s):  
VE Rogers
Keyword(s):  
Root Rot ◽  
Clay Soil ◽  
New South ◽  
Combined Effects ◽  
Phytophthora Root Rot ◽  
Aphid Infestation ◽  
South Wales ◽  
Heavy Clay ◽  
Large Populations ◽  
The Usa

Eighteen lucerne cultivars were sown at Deniliquin, New South Wales, in 1976. The aim of the trial was to assess these cultivars for their performance on an irrigated heavy clay soil infected by P. megasperma. The unforeseen arrival of the spotted alfalfa aphid (SAA) in December 1977 complicated the original assessment, but provided an opportunity of assessing the combined effects of SAA and P. megasperma. Twelve of the cultivars were introduced from the USA, and six were Australian lines. The American cultivars were AS1 3, AS1 3R, AS49, AS49R, WL451, WL501 R, WL508, WL512, DeKalb 167, DeKalb 185, Resistador II and Lahontan. None of these was damaged by SAA, and all except WL508 appeared to be well adapted to the heavy clay soil. The Australian cultivars Hunter River, Paravivo and Siro Peruvian were all badly affected by the aphid, and in Siro Peruvian the loss in production was accentuated by Phytophthora root rot. The Australian cultivar Falkiner and its parent line, Lahontan Cycle 4, carried large populations of aphids, but the effect on their production was only slight and temporary. Another Australian line, C3 Composite, yielded well until the aphid infestation, when its yield was temporarily reduced, but recovered after the aphids disappeared. Neither Falkiner nor C3 Composite was affected by root rot.

Effect of long-fallow on soil quality and cotton lint yield in an irrigated, self-mulching, grey Vertosol in the central-west of New South Wales

Soil Research ◽  
1998 ◽  
Vol 36 (4) ◽  
pp. 621 ◽  
Author(s):  
N. R. Hulugalle ◽  
P. C. Entwistle ◽  
J. L. Cooper ◽  
S. J. Allen ◽  
D. B. Nehl
Keyword(s):  
Soil Quality ◽  
Root Rot ◽  
New South ◽  
New South Wales ◽  
Plastic Limit ◽  
Cotton Lint ◽  
Organic C ◽  
Black Root Rot ◽  
Nitrate N ◽  
South Wales

Reduced crop growth rates (‘long-fallow disorder’) can be a feature of long-fallow cotton (cotton, alternating with a bare fallow, is sown every other year). This is usually attributed to decreased development of arbuscular mycorrhiza (AM), although associated soil physical, chemical, and biological properties are very rarely reported. A study was conducted from 1993 to 1997 in a grey, self-mulching Vertosol in the central-west of New South Wales to characterise soil properties under long-fallow cotton with a view to identifying soil factors other than AM that could contribute to cotton growth rate reductions. Soil quality indicators monitored were compaction (bulk density and air-filled porosity), strength (cone resistance), plastic limit, exchangeable cations, nitrate-N, pH, organic C, development of AM, and incidence of cotton root diseases. In comparison with continuous cotton, long-fallow cotton had lower soil strength, and lower plastic limit. Exchangeable Ca and Mg were higher with continuous cotton only in 1994. Higher nitrate-N was also observed with long-fallow during the first fallow phase of the experiment. Long-fallow did not have any significant effect on soil organic carbon. However, a net decline in soil organic C and exchangeable Mg occurred with both treatments. During the cotton phase, subsoil nitrate-N and incidence of black root rot were lower with long-fallow cotton. Uptake of nitrogen by continuous cotton may have been reduced by greater severity of black root rot. Vegetative and reproductive growth, water extraction, and cotton lint yields in long-fallow cotton plots were higher than those in continuous cotton plots. AM development was similar with continuous cotton and long-fallow cotton. Compared with long-fallow cotton, the lower lint yield in continuous cotton was thought to be due to the interactive effects of declining nutrient availability, higher soil strength, and greater severity of black root rot causing decreases in nutrient and water uptake.

Pathogenicity of root and stolon-colonising fungi to white clover

2001 ◽  
Vol 41 (6) ◽  
pp. 763 ◽  
Author(s):  
M. I. Zahid ◽  
G. M. Gurr ◽  
A. Nikandrow ◽  
W. J. Fulkerson ◽  
H. I. Nicol
Keyword(s):  
Plant Growth ◽  
White Clover ◽  
Root Rot ◽  
New South ◽  
Field Soil ◽  
Pythium Irregulare ◽  
Phytophthora Megasperma ◽  
South Wales ◽  
Roots In Vitro

Fungi isolated from white clover plants growing in dairy pastures in northern New South Wales and south-eastern Queensland were tested for their pathogenicity to seedlings, excised stolons and mature white clover plants. Thirty out of 65 isolates tested, including species of Fusarium, Phytophthora, Pythium, Rhizoctonia, Phoma, Codinaea, Gliocladium, Microsphaeropsis, Trichoderma, Nectria and Macrophomina, were pathogenic to white clover roots in vitro. Ten of the fungi, including the genera Alternaria, Colletotrichum, Drechslera, Fusarium, Phoma, Macrophomina, Phomopsis and Rhizoctonia, caused stolon rot symptoms. Of the 23 fungi tested on seedlings and mature white clover plants Phytophthora megasperma, Phoma nebulosa and Pythium irregulare were the most pathogenic to both seedlings and mature plants. Root rot and plant growth suppression was more severe in pot tests using field soil compared with pasteurised potting mix. Novel methods are described for testing pathogenicity to excised stolons.

Phytophthora drechsleri Tucker and Pythium spp. as pathogens of safflower in New South Wales

1973 ◽  
Vol 13 (63) ◽  
pp. 455 ◽  
Author(s):  
G Stovold
Keyword(s):  
Root Rot ◽  
New South ◽  
New South Wales ◽  
Field Capacity ◽  
Pythium Ultimum ◽  
Carthamus Tinctorius ◽  
Pythium Myriotylum ◽  
Pythium Irregulare ◽  
South Wales ◽  
Phytophthora Drechsleri

Pythiaceous fungi associated with a widespread root rot disease of safflower (Carthamus tinctorius) in New South Wales include Phytophthora drechsleri, Pythium myriotylum, Pythium ultimum Pythium irregulare, Pythium acanthicum, and a number of sterile Pythium spp. Pathogenicity of these fungi was tested against safflower seedlings and older plants growing either in soil with moisture content at field capacity or in flooded soil. Phytophthora drechsleri, Pythium myriotylum, Pythium ultimum and Pythiumirregulare caused severe pre-emergence damping off. When safflower plants, three and eight weeks old, were inoculated with each of the fungi, only Phytophthora drechsleriand Pythium myriotylum killed a high proportion of plants. The pathogenicity of Phytophthora drechsleri, Pythium myriotylum, Pythium ultimum, and Pythium irregulare was increased by flooding the soil for ninety hours after inoculation. Phytophthora drechsleri was isolated from naturally infected saffron thistle (Carthamus lanatus). Cross inoculation tests with Phytophthora drechsleri isolates from safflower and saffron thistle showed that both isolates could infect each host. Saffron thistle could be an important alternative host of Phytophthora drechsleri in the field. It is concluded that Phytophthora drechsleri is the major cause of root rot of safflower in New South Wales.

Sign in / Sign up

Export Citation Format

Share Document