Mapping QTL for dollar spot resistance in creeping bentgrass (Agrostis stolonifera L.)

Dollar spot caused by Sclerotinia homoeocarpa F. T. Bennett is the most economically important turf disease on golf courses in North America. Dollar spot resistance in a creeping bentgrass cultivar would greatly reduce the frequency, costs, and environmental impacts of fungicide application. Little work has been done to understand the genetics of resistance to dollar spot in creeping bentgrass. Therefore, QTL analysis was used to determine the location, number and effects of genomic regions associated with dollar spot resistance in the field. To meet this objective, field inoculations using a single isolate were performed over 2 years and multiple locations using progeny of a full sib mapping population ‘549 × 372’. Dollar spot resistance seems to be inherited quantitatively and broad sense heritability for resistance was estimated to be 0.88. We have detected one QTL with large effect on linkage group 7.1 with LOD values ranging from 3.4 to 8.6 and explaining 14–36% of the phenotypic variance. Several smaller effect QTL specific to rating dates, locations and years were also detected. The association of the tightly linked markers with the LG 7.1 QTL based on 106 progeny was further examined by single marker analysis on all 697 progeny. The high significance of the QTL on LG 7.1 at a sample size of 697 (P < 0.0001), along with its consistency across locations, years and ratings dates, indicated that it was stable over environments. Markers tightly linked to the QTL can be utilized for marker-assisted selection in future bentgrass breeding programs.

[1]  J. Trevors,et al.  Evaluation of Composts for Suppression of Dollar Spot (Sclerotinia homoeocarpa) of Turfgrass. , 2002, Plant disease.

[2]  E. Lander,et al.  Mendelian factors underlying quantitative traits in tomato: comparison across species, generations, and environments. , 1991, Genetics.

[3]  QTL analysis of flower and fruit traits in sour cherry , 2000, Theoretical and Applied Genetics.

[4]  M. Casler,et al.  Plant responses and characteristics associated with dollar spot resistance in creeping bentgrass , 2004 .

[5]  G. Jiang,et al.  Isolate-specific QTLs for partial resistance to Puccinia hordei in barley , 1999, Theoretical and Applied Genetics.

[6]  M. Rodier-Goud,et al.  Identification of QTLs involved in the resistance to South American leaf blight (Microcyclus ulei) in the rubber tree , 2000, Theoretical and Applied Genetics.

[7]  K. Eskridge,et al.  Identification of QTLs for Resistance to Sclerotinia sclerotiorum in Soybean , 2001 .

[8]  G. Boland,et al.  Biology and Management of Dollar Spot (Sclerotinia homoeocarpa); an Important Disease of Turfgrass , 1999 .

[9]  A. Price,et al.  Loci controlling partial resistance to rice blast do not show marked QTL x environment interaction when plant nitrogen status alters disease severity. , 2005, The New phytologist.

[10]  Z. Li,et al.  RFLP-facilitated investigation of the quantitative resistance of rice to brown planthopper (Nilaparvata lugens) , 2002, Theoretical and Applied Genetics.

[11]  Michael D. Casler,et al.  Response of bentgrass cultivars to sclerotinia homoeocarpa isolates representing 10 vegetative compatibility groups , 2006 .

[12]  W. Zhai,et al.  Mapping quantitative trait loci controlling sheath blight resistance in two rice cultivars (Oryza sativa L.) , 2000, Theoretical and Applied Genetics.

[13]  J. M. Vargas,et al.  Management of Turfgrass Diseases , 1981 .

[14]  L. Burpee,et al.  Control of Dollar Spot of Creeping Bentgrass Caused by an Isolate of Sclerotinia homoeocarpa Resistant to Benzimidazole and Demethylation-Inhibitor Fungicides. , 1997, Plant disease.

[15]  P. Miklas,et al.  QTL Conditioning Physiological Resistance and Avoidance to White Mold in Dry Bean , 2001 .

[16]  M. Lorieux,et al.  Identification of five new blast resistance genes in the highly blast-resistant rice variety IR64 using a QTL mapping strategy , 2003, Theoretical and Applied Genetics.

[17]  S. Tanksley,et al.  RFLP Mapping in Plant Breeding: New Tools for an Old Science , 1989, Bio/Technology.

[18]  M. Casler,et al.  Turfgrass Biology: Genetics and Breeding , 2002 .

[19]  G. Jung,et al.  Linkage map construction in allotetraploid creeping bentgrass (Agrostis stolonifera L.) , 2005, Theoretical and Applied Genetics.

[20]  A. Melchinger,et al.  Quantitative trait locus (QTL) mapping using different testers and independent population samples in maize reveals low power of QTL detection and large bias in estimates of QTL effects. , 1998, Genetics.

[21]  David BotsteinS’B.  Mapping Mendelian Factors Underlying Quantitative Traits Using RFLP Linkage Maps , 2002 .

[22]  C. Maliepaard,et al.  MapQTL (tm) version 3.0: Software for the calculation of QTL positions on genetic maps , 1999 .

[23]  S. E. Hart,et al.  Creeping Bentgrass (Agrostis Stolonifera) Tolerance to Sulfosulfuron , 2008, Weed Technology.

[24]  N. Young.  QTL mapping and quantitative disease resistance in plants. , 1996, Annual review of phytopathology.

[25]  M. Saha,et al.  Genetic linkage mapping of an annual × perennial ryegrass population , 2004, Theoretical and Applied Genetics.

[26]  S. Leong,et al.  QTL mapping of resistance to gray leaf spot in ryegrass , 2005, Theoretical and Applied Genetics.

[27]  D. Stuthman,et al.  Quantitative trait loci for partial resistance to crown rust, Puccinia coronata, in cultivated oat, Avena sativa L. , 2005, Theoretical and Applied Genetics.

[28]  Michael D. Casler,et al.  Inheritance of Dollar Spot Resistance in Creeping Bentgrass , 2003 .