EFFECT OF Phytophthora megasperma ON YIELD AND SURVIVAL OF RESISTANT AND SUSCEPTIBLE ALFALFA CULTIVARS

1981 ◽  
Vol 61 (4) ◽  
pp. 955-960 ◽  
Author(s):  
M. A. FARIS ◽  
F. E. SABO
Keyword(s):  
Root Rot ◽  
Field Conditions ◽  
Yield Potential ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Resistant Cultivars ◽  
Central Experimental Farm

Performance of some artificially inoculated Phytophthora root rot (PRR) resistant and susceptible alfalfa cultivars was determined under field conditions at the Central Experimental Farm, Ottawa. Yields of both resistant and susceptible cultivars were reduced after inoculation; however, the resistant cultivars outyielded the susceptible ones. The resistant, inoculated cultivars showed less winterkill. There is still a need for improving PRR resistance in alfalfa, and thus increasing yield potential.

RCAT Persian soybean

1991 ◽  
Vol 71 (1) ◽  
pp. 175-176
Author(s):  
G. R. Ablett ◽  
W. D. Beversdorf
Keyword(s):  
Glycine Max ◽  
Root Rot ◽  
Yield Potential ◽  
Maturity Group ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Group I ◽  
Glycine Max L ◽  
Cultivar Description ◽  
Late Maturity

RCAT Persian is a mid-late Maturity Group I soybean [Glycine max L. (Merr.)] cultivar with excellent yield potential, good lodging tolerance and resistance to most races of phytophthora root rot caused by Phytophthora megasperma f. sp. glycinea (Pmg) found in Ontario. Key words: Soybean, cultivar description

Lack of control of phytophthora root in lucerne (Medicago sativa) by foliar applications of phosphorus

1991 ◽  
Vol 31 (4) ◽  
pp. 503
Author(s):  
KF Lowe ◽  
MJ Ryley ◽  
TM Bowdler
Keyword(s):  
High Risk ◽  
Medicago Sativa ◽  
Root Rot ◽  
Dry Matter ◽  
Small Reduction ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Resistant Cultivars ◽  
Matter Production ◽  
Lack Of Control

Application of phosphonate was investigated as a means of controlling phytophthora root rot (Phytophthora megasperma f. sp. medicaginis) in lucerne (Medicago sativa). Foliar sprays of the chemical at rates of 2, 4 and 8 g/L did not improve the persistence or dry matter production of susceptible or resistant cultivars of lucerne, despite a small reduction in the degree of damage inflicted on lucerne plants by a severe epiphytotic of the disease. Regular monthly applications gave no better control than single applications at establishment or at the time of the development of an epiphytotic. It is concluded that phosphonate is not efficacious in controlling phytophthora root rot in lucerne and will not improve the performance of susceptible cultivars in high risk situations.

RCAT Angora soybean

1993 ◽  
Vol 73 (1) ◽  
pp. 179-180
Author(s):  
G. R. Ablett ◽  
J. W. Tanner
Keyword(s):  
Glycine Max ◽  
Key Words ◽  
Root Rot ◽  
Yield Potential ◽  
Maturity Group ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Glycine Max L ◽  
Cultivar Description ◽  
Late Maturity

RCAT Angora is a mid-late Maturity Group II soybean (Glycine max (L.) Merr.) cultivar with excellent yield potential and resistance to most races of phytophthora root rot caused by Phytophthora megasperma f. sp. glycinea (RMG) found in Ontario. Key words: Soybean, cultivar description

RCAT Columbus soybean

1996 ◽  
Vol 76 (1) ◽  
pp. 135-136
Author(s):  
G. R. Ablett ◽  
B.T. Stirling ◽  
J. D. Fischer
Keyword(s):  
Root Rot ◽  
Yield Potential ◽  
Maturity Group ◽  
Lodging Resistance ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Good Tolerance ◽  
Glycine Max L ◽  
Cultivar Description ◽  
Late Maturity

RCAT Columbus is a late Maturity Group II soybean [Glycine max (L.) Merr.] cultivar with excellent yield potential and lodging resistance and with good tolerance to phytophthora root rot caused by Phytophthora megasperma f. sp. glycinea. Key words: Soybean, cultivar description

RCAT Tabby soybean

1993 ◽  
Vol 73 (4) ◽  
pp. 1103-1104
Author(s):  
G. R. Ablett ◽  
J. W. Tanner
Keyword(s):  
Glycine Max ◽  
Key Words ◽  
Root Rot ◽  
Yield Potential ◽  
Maturity Group ◽  
Lodging Resistance ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Glycine Max L ◽  
Cultivar Description

RCAT Tabby is a mid Maturity Group II soybean [Glycine max (L.) Merr.] cultivar with excellent yield potential, lodging resistance and with resistance to most races of phytophthora root rot caused by Phytophthora megasperma f. sp. glycinea (PMG) found in Ontario. Key words: Soybean, cultivar description

Brock soybean

1993 ◽  
Vol 73 (1) ◽  
pp. 175-176 ◽  
Author(s):  
G. R. Ablett ◽  
J. W. Tanner
Keyword(s):  
Glycine Max ◽  
Key Words ◽  
Root Rot ◽  
Yield Potential ◽  
Maturity Group ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Group I ◽  
Glycine Max L ◽  
Cultivar Description

Brock is a mid-Maturity Group I soybean (Glycine max (L.) Merr.) cultivar with excellent yield potential and lodging tolerance and with resistance to most races of phytophthora root rot caused by Phytophthora megasperma f. sp. glycinea (PMG) found in Ontario. Key words: Soybean, cultivar description

Factors contributing to poor lucerne persistence in southern Queensland

1977 ◽  
Vol 17 (89) ◽  
pp. 998 ◽  
Author(s):  
JAG Irwin
Keyword(s):  
Bacterial Wilt ◽  
Root Rot ◽  
Crown Rot ◽  
Wide Spread ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Colletotrichum Trifolii ◽  
Disease Survey ◽  
Disease Surveys ◽  
Made In

Lucerne disease surveys made in southern Queensland have shown the presence of seven fungal root and crown diseases. The two most wide spread and serious diseases are Phytophthora root rot (Phytophthora megasperma) and Colletotrichum crown rot (Colletotrichum trifolii). The general disease survey did not reveal the presence of bacterial wilt (Corynebacterium insidiosum) in Queensland. Studies made on the survival of lucerne populations for 2.5 years at three sites in Queensland have shown that disease was the major cause of all detected plant deaths.

Reaction of lucerne cultivars to Phytophthora megasperma, the cause of a root rot in Queensland

1974 ◽  
Vol 14 (69) ◽  
pp. 561 ◽  
Author(s):  
JAG Irwin
Keyword(s):  
Medicago Sativa ◽  
Root Rot ◽  
Controlled Environment ◽  
Field Site ◽  
Causal Organism ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Disease Surveys ◽  
Infested Field ◽  
Experimental Strains

The causal organism of Phytophthora root rot of lucerne (Medicago sativa) in Queensland was identified as Phytophthora megasperma var. sojae and a brief description of the organism is included. The results of disease surveys show that Phytophthora root rot is widespread and causes serious losses in lucerne in south eastern Queensland. A collection of lucerne cultivars and strains was screened for resistance to P. megasperma var. sojae both in controlled environment chambers and in a naturally infested field site. The cultivar Lahontan and the experimental strains ESI, BDSI, ECRSI and Combined showed high levels of resistance in both situations.

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.

Recurrent selection for resistance to Stemphylium vesicarium within the lucerne cultivars Trifecta and Sequel

1989 ◽  
Vol 29 (2) ◽  
pp. 189 ◽  
Author(s):  
RA Bray ◽  
JAG Irwin
Keyword(s):  
Leaf Spot ◽  
Root Rot ◽  
Recurrent Selection ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Stemphylium Vesicarium ◽  
Colletotrichum Trifolii ◽  
Resistant Lines ◽  
Selection For

Two cycles of recurrent selection for resistance to Stemphylium leaf spot (caused by Stemphylium vesicarium) based on half-sib family performance were made within the lucerne cultivars Trifecta and Sequel. Within Trifecta, 1 generation of selection was sufficient to increase the level of resistance to that of UC 1249 (resistant check), while 2 generations were necessary to obtain equivalent levels of resistance in Sequel. The Stemphylium resistant lines maintained adequate levels of resistance to anthracnose (caused by Colletotrichum trifolii) and Phytophthora root rot (caused by Phytophthora megasperma f. sp. medicaginis) on the basis of glasshouse tests.

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