scholarly journals Mapping of Quantitative Trait Loci for Scab Resistance in Apple (Malus × Domestica)

2021 ◽  
Author(s):  
Saba Mir ◽  
Aafreen Sakina ◽  
Khalid Z. Masoodi ◽  
Khalid M. Bhat ◽  
Bilal A. Padder ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Venturia Inaequalis ◽  
Durable Resistance ◽  
Genetic Resistance ◽  
In Silico Analysis ◽  
Genomic Region ◽  
Scab Resistance ◽  
Chromosome 2 ◽  
Trait Loci

Abstract Scab caused by Venturia inaequalis (Cke.) Wint. is the most important fungal disease of apple. Fungicide application is a widely practiced method of disease control. The use of chemicals is however, cost intensive, tedious and ecologically unsafe. Development of genetic resistance and breeding of resistant cultivars is most reliable and a safest option. One such source of scab resistance happens to be the variety ‘Shireen’, released from SKUASTKashmir. However, till date the nature of resistance and its genetic control has not been characterized. The aim of this research was to elucidate the genetic basis of scab resistance in Shireen. The present study helped us to identify two quantitative trait loci (QTLs) on chromosome 2 and 8 and six potential CDGs for the polygenic resistance in ‘Shireen’. The genomic region corresponding to the mapped QTLs in LG 2 and LG 8 of ‘Shireen’ was examined for candidate genes possibly related to scab resistance using in silico analysis. The QTLs mapped in the genetic background of Shireen are the novel QTLs and may be transferred to desirable genetic backgrounds and provide opportunities for isolation and cloning of genes apart from their utility in order to achieve durable resistance to scab.

scholarly journals Quantitative Trait Loci (QTL) Analysis Reveals Both Broad-Spectrum and Isolate-Specific QTL for Scab Resistance in an Apple Progeny Challenged with Eight Isolates of Venturia inaequalis

2004 ◽  
Vol 94 (4) ◽  
pp. 370-379 ◽  
Author(s):  
F. Calenge ◽  
A. Faure ◽  
M. Goerre ◽  
C. Gebhardt ◽  
W. E. Van de Weg ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Quantitative Trait ◽  
Venturia Inaequalis ◽  
Scab Resistance ◽  
Breeding Programs ◽  
Apple Breeding ◽  
Trait Loci ◽  
New Races

The major scab resistance gene Vf, extensively used in apple breeding programs, was recently overcome by the new races 6 and 7 of the fungal pathogen Venturia inaequalis. New, more durable, scab resistance genes are needed in apple breeding programs. F1 progeny derived from the cross between partially resistant apple cv. Discovery and apple hybrid ‘TN10-8’ were inoculated in the greenhouse with eight isolates of V. inaequalis, including isolates able to overcome Vf. One major resistance gene, Vg, and seven quantitative trait loci (QTL) were identified for resistance to these isolates. Three QTL on linkage group (LG)12, LG13, and LG15 were clearly isolate-specific. Another QTL on LG5 was detected with two isolates. Three QTL on LG1, LG2, and LG17 were identified with most isolates tested, but not with every isolate. The QTL on LG2 displayed alleles conferring different specificities. This QTL co-localized with the major scab resistance genes Vr and Vh8, whereas the QTL on LG1 colocalized with Vf. These results contribute to a better understanding of the genetic basis of the V. inaequalis-Malus × domestica interaction.

scholarly journals Acibenzolar-S-methyl and resistance quantitative trait loci complement each other to control apple scab and fire blight

Plant Disease ◽  
2020 ◽  
Author(s):  
Juliette Bénéjam ◽  
Elisa Ravon ◽  
Matthieu Gaucher ◽  
Marie-Noëlle Brisset ◽  
Charles-Eric Durel ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Induced Resistance ◽  
Quantitative Trait ◽  
Fire Blight ◽  
Apple Scab ◽  
Genetic Resistance ◽  
Water Control ◽  
Resistance Qtls ◽  
Trait Loci ◽  
Pre Treatment

Diversifying disease control methods is a key strategy to sustainably reduce pesticides. Plant genetic resistance has long been used to create resistant varieties. Plant resistance inducers (PRI) are also considered to promote crop health, but their effectiveness is partial and can vary according to the environment and the plant genotype. We investigated the putative interaction between intrinsic (genetic) and PRI-induced resistance in apple when affected by scab and fire blight diseases. A large F1 mapping population was challenged by each disease after a pre-treatment with acibenzolar-S-methyl (ASM) and compared with the water control. Apple scab and fire blight resistance quantitative trait loci (QTLs) were detected in both conditions and compared. ASM exhibited a strong effectiveness in reducing both diseases. When combined, QTL-controlled and ASM-induced resistance acted complementarily to reduce the symptoms from 85% to 100% depending on the disease. In our conditions, resistance QTLs were only slightly or rarely affected by ASM treatment, despite their probable implication in various stages of the resistance build-up. Implications of these results are discussed considering already known results, the underlying mechanisms, cross-protection of both types of resistance against pathogen adaptation, and practical application in orchard conditions.

The effects of three muscling Quantitative Trait Loci on growth patterns of crossbred lambs

2009 ◽  
Vol 2009 ◽  
pp. 40-40
Author(s):  
N R Lambe ◽  
J M Macfarlane ◽  
A Masri ◽  
O Matika ◽  
W Haresign ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Growth Rates ◽  
Quantitative Trait ◽  
Growth Patterns ◽  
Chromosome 2 ◽  
Chromosome 18 ◽  
Fast Growing ◽  
Trait Loci

Texel Muscling QTL (TM-QTL) and LoinMaxTM (LM-QTL) are located on chromosome 18 in Texel and Poll Dorset sheep, respectively, and have been shown to positively affect muscling of the loin in crossbred lambs carrying one copy of the QTL (Macfarlane et al., 2008, Masri et al., 2009). MyoMaxTM (MM-QTL), found on chromosome 2 of Texel sheep, increases muscling and decreases fatness in lambs of different genetic backgrounds (Campbell and McLaren, 2007). No differences in live weights, carcass weights or growth rates have been associated with these QTL to date. However, there is further need to investigate the effects of the three QTL on growth patterns in commercial crossbred populations, where fast-growing slaughter lambs of good carcass weights and quality are a prerequisite.

Identification and Validation of Quantitative Trait Loci for Partial Resistance to Crown Rust in Oat

2010 ◽  
Vol 100 (5) ◽  
pp. 511-521 ◽  
Author(s):  
M. Acevedo ◽  
E. W. Jackson ◽  
J. Chong ◽  
H. W. Rines ◽  
S. Harrison ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Recombinant Inbred Lines ◽  
Major Gene ◽  
Natural Infection ◽  
Durable Resistance ◽  
Field Tests ◽  
Crown Rust ◽  
Rust Disease ◽  
Trait Loci

Management of oat crown rust disease with host resistance is challenging because major gene resistance is generally short lived. Partially resistant oat cultivars could benefit oat growers by providing more durable resistance. The objective of this study was to validate and discover quantitative trait loci (QTL) affecting crown rust resistance in the partially resistant oat line MN841801-1 using conventional and molecular assessments of disease produced in single-race greenhouse inoculations, single-race polycyclic field tests, and under natural infection in disease-conducive environments. Crown rust was assessed on 150 F6:9 MN841801-1/‘Noble-2’ recombinant inbred lines. In total, eight QTL associated with MN841801-1 alleles were detected. Of these, seven matched QTL previously identified while a new QTL (Prq8) was detected on linkage group MN13. Four QTL (Prq1a, Prq2, Prq7, and Prq8) were consistently detected and predicative genetic assays for these QTL should be developed for future validation in additional genetic backgrounds.

scholarly journals A Genome-Wide Meta-Analysis of Rice Blast Resistance Genes and Quantitative Trait Loci Provides New Insights into Partial and Complete Resistance

2008 ◽  
Vol 21 (7) ◽  
pp. 859-868 ◽  
Author(s):  
Elsa Ballini ◽  
Jean-Benoît Morel ◽  
Gaétan Droc ◽  
Adam Price ◽  
Brigitte Courtois ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Resistance Genes ◽  
Quantitative Trait ◽  
Rice Blast ◽  
Blast Resistance ◽  
Durable Resistance ◽  
Rice Genome ◽  
Blast Disease ◽  
Trait Loci ◽  
Blast Resistance Genes

The completion of the genome sequences of both rice and Magnaporthe oryzae has strengthened the position of rice blast disease as a model to study plant–pathogen interactions in monocotyledons. Genetic studies of blast resistance in rice were established in Japan as early as 1917. Despite such long-term study, examples of cultivars with durable resistance are rare, partly due to our limited knowledge of resistance mechanisms. A rising number of blast resistance genes and quantitative trait loci (QTL) have been genetically described, and some have been characterized during the last 20 years. Using the rice genome sequence, can we now go a step further toward a better understanding of the genetics of blast resistance by combining all these results? Is such knowledge appropriate and sufficient to improve breeding for durable resistance? A review of bibliographic references identified 85 blast resistance genes and approximately 350 QTL, which we mapped on the rice genome. These data provide a useful update on blast resistance genes as well as new insights to help formulate hypotheses about the molecular function of blast QTL, with special emphasis on QTL for partial resistance. All these data are available from the OrygenesDB database.

Exotic Scab Resistance Quantitative Trait Loci Effects on Soft Red Winter Wheat

Crop Science ◽  
2011 ◽  
Vol 51 (3) ◽  
pp. 924-933 ◽  
Author(s):  
Jing Kang ◽  
Anthony Clark ◽  
David Van Sanford ◽  
Carl Griffey ◽  
Gina Brown-Guedira ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Winter Wheat ◽  
Quantitative Trait ◽  
Scab Resistance ◽  
Soft Red Winter Wheat ◽  
Trait Loci ◽  
Red Winter Wheat

Identification of stably expressed quantitative trait loci for cooked rice elongation in non-Basmati varieties

Genome ◽  
2008 ◽  
Vol 51 (2) ◽  
pp. 104-112 ◽  
Author(s):  
L. L. Liu ◽  
X. Y. Yan ◽  
L. Jiang ◽  
W. W. Zhang ◽  
M. Q. Wang ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Recombinant Inbred Lines ◽  
Basmati Rice ◽  
Eating Quality ◽  
Chromosome 2 ◽  
Elongation Ratio ◽  
Substitution Lines ◽  
Chromosome Segment Substitution Lines ◽  
Trait Loci

The elongation of the cooked grain determines the cooking and eating quality of Basmati rice. The identification of stable quantitative trait loci (QTLs), especially those from non-Basmati types, will extend the genetic basis of the Basmati type and facilitate the breeding of high-quality varieties. A set of recombinant inbred lines derived from an indica × japonica hybrid was used to identify QTLs controlling the elongation ratio (ER), elongation index (EI), and water absorption (WA) of the cooked grain. Three ER QTLs on chromosomes 2, 4, and 12, two EI QTLs on chromosomes 2 and 5, and two WA QTLs on chromosomes 2 and 6 were detected. Four of these QTLs were validated using a set of established chromosome segment substitution lines. The genetic effect of qER-2 was explored in an analysis of segregating generations, using 8 newly developed simple sequence repeat markers. Two tightly linked loci (qER-2a and qER-2b) were identified on chromosome 2.

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