scholarly journals Genes for Resistance to Powdery Mildew Races 1 and 2U.S. in Melon PI 313970

HortScience ◽  
2003 ◽  
Vol 38 (4) ◽  
pp. 591-594 ◽  
Author(s):  
James D. McCreight

Powdery mildew is a major problem in melon (Cucumis melo L.) production worldwide. Three genes for resistance to Sphaerotheca fuliginea (Schlecht. ex Fr.) Poll. race 1 and race 2U.S. were identified in growth chamber and greenhouse tests in the cross of PI 313970 × `Top Mark'. A recessive gene conditioned resistance of true leaves to race 1. A recessive gene appeared to condition resistance of cotyledons to race 2U.S., although a second recessive gene may be involved. A semi-dominant gene conditioned resistance of true leaves to race 2U.S. Limited data suggested linkage of the recessive gene for resistance to race 1 and the semi-dominant gene for resistance to race 2U.S. The resistance reaction of PI 313970 to infection of true leaves by race 2U.S. included water-soaked spots and resistant blisters, but segregation data for the resistant blister reaction were inconclusive. Allelic relationships of these genes with previously reported melon powdery mildew resistance genes remain to be determined.

2021 ◽  
Author(s):  
Haonan Cui ◽  
Chao Fan ◽  
Zhuo Ding ◽  
Xuezheng Wang ◽  
Lili Tang ◽  
...  

Abstract Cucumis melo L. is an economically important crop, the production of which is threatened by the prevalence of melon powdery mildew (PM) infections. We herein utilized the MR-1 (P1; resistant to PM) and M4-7 (P2; susceptible to PM) accessions to assess the heritability of PM (race 1) resistance in these melon plants. PM resistance in MR-1 leaves was linked to a dominant gene (CmPMRl), whereas stem resistance was under the control of a recessive gene (CmPMrs), with the dominant gene having an epistatic effect on the recessive gene. The CmPMRl gene was mapped to a 50 Kb interval on chromosome 12, while CmPMrs was mapped to an 89 Kb interval on chromosome 10. The CmPMRl candidate gene MELO3C002441 and the CmPMrs candidate gene MELO3C012438 were identified through sequence alignment, functional annotation, and expression pattern analyses of all genes within these respective intervals. MELO3C002441 and MELO3C012438 were both localized to the cellular membrane and were contained conserved NPR gene-like and MLO domains, respectively, which were linked to PM resistance. In summary, we identified patterns of PM resistance in the disease-resistant MR-1 melon cultivar, and conducted finally-mapping to identify two putative genes linked to resistance. Our results offer new genetic resources and markers guide the future molecular marker-assisted breeding of PM-resistant melon.


2006 ◽  
Vol 131 (1) ◽  
pp. 59-65 ◽  
Author(s):  
James D. McCreight

Powdery mildew is a serious disease of melon (Cucumis melo L.) worldwide. Twenty-two melon cultigens have been used to define 22 reported races of the pathogen Podosphaera xanthii (sect. Sphaerotheca) xanthii (Castag.) U. Braun & N. Shish. Comb. nov. [syn. Sphaerotheca fuliginea (Schlecht. ex Fr.) Poll.]. Discrepancies in the reactions of eight cultigens to populations of P. xanthii races 1 and 2 in California, Japan, and Spain revealed genetic differences among them that can be used to differentiate P. xanthii race 1 and 2 populations in these countries. Implicit in these results is the existence of previously unknown virulence factors in these populations of P. xanthii races 1 and 2 that permit designation of new races of P. xanthii on melon. Synthesis of these results with previous reports resulted in the identification of 28 putative races of P. xanthii on melon that include eight variants of race 1 and six variants of race 2. Six of the cultigens exhibited resistant blisters in response to heavy infection by P. xanthii in field and greenhouse tests.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534b-534
Author(s):  
James D. McCreight

Yellowing of melon (Cucumis melo L.) incited by lettuce infectious yellows virus (LIYV) reduces yield and fruit quality of infected plants. LIYV is transmitted only by the sweetpotato whitefly (Bemisia tabaci Genn.). Two naturally infected field tests indicated several potential sources of resistance to LIYV. PI 124112 and `Snake Melon' had mild symptoms in both field tests whereas PI 313970 was asymptomatic in the test in which it was included. In greenhouse tests using controlled inoculation, PI 313970 was asymptomatic, had negative ELISA assays for LIYV, and was negative for LIYV in serial transfers to Chenopodium. `Top Mark' and `PMR 5' were symptomatic, had positive ELISA assays for LIYV, and were positive for LIYV in serial transfers to Chenopodium in these greenhouse tests. Limited data indicate that resistance in PI 313970 is conditioned by a single, dominant gene.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 888a-888 ◽  
Author(s):  
James D. McCreight ◽  
Michael D. Coffey ◽  
Thomas A. Turini ◽  
Michael E. Matheron

Races 1 and 2 of Podosphaera xanthii (syn. Sphaerotheca fuliginea) were defined in Imperial Valley, Calif. 1938 when P. xanthii overcame genetic resistance in `PMR 45'. Race 3 was first observed in the U.S. in 1976 in Texas; 15 additional races of P. xanthii have been reported in the literature since 1996. Races 1 and 2 have been common in Arizona and California based upon the effectiveness of the powdery mildew resistance genes in commercially available melon cultivars grown in these states. Field data from 11 commonly used melon P. xanthii race differentials in 2001 and 2002 indicated the presence of race 1 in the Imperial Valley and San Joaquin Valley of California, and Yuma, Arizona. In spring 2003, the powdery mildew race situation changed. The first evidence was the occurrence of a severe and widespread infection of powdery mildew in a commercial cantaloupe field. The 11 powdery mildew race differentials were susceptible to powdery mildew in a nearby replicated field test. PI 313970, a melon from India, was resistant to this apparent new race of powdery mildew.


Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2645-2651 ◽  
Author(s):  
Yanmin Qie ◽  
Yuan Sheng ◽  
Hongxing Xu ◽  
Yuli Jin ◽  
Feifei Ma ◽  
...  

Chinese wheat landrace Dahongtou was resistant to 35 of 38 tested Chinese isolates of Blumeria graminis f. sp. tritici at the seedling stage. Genetic analysis of the F2 populations and their derived F2:3 families of crosses of Dahongtou with the susceptible varieties Mingxian 169 and Huixianhong indicated that the resistance of Dahongtou to B. graminis f. sp. tritici isolate E09 was conferred by a single recessive gene, tentatively designated as pmDHT. The gene was mapped to chromosome arm 7BL and flanked by markers Xwmc526/XBE443877 and Xgwm611/Xwmc511 at genetic distances of 0.8 and 0.3 cM, respectively. The chromosomal position of pmDHT was similar to the multi-allelic Pm5 locus on 7BL. Allelism tests with crosses of Dahongtou with Fuzhuang 30 (Pm5e) and Xiaobaidong (mlxbd) indicated that pmDHT was allelic to both Pm5e and mlxbd. However, pmDHT showed a different pattern of resistance to the 38 B. graminis f. sp. tritici isolates compared with wheat lines with Pm5a, Pm5b, Pm5e, mlxbd, and PmHYM and also differed from PmSGA. Thus, pmDHT was identified most likely as a new allele or at least a closely linked gene of the Pm5 locus. This gene can be transferred into susceptible wheat cultivars/lines and pyramided with other resistance genes through marker-assisted selection to improve powdery mildew resistance.


1978 ◽  
Vol 20 (1) ◽  
pp. 151-153 ◽  
Author(s):  
R. I. Buzzell ◽  
Jerry H. Haas

In greenhouse tests with Microsphaera diffusa Cke &Pk. on soybeans (Glycine max (L.) Merr.), adult plant resistance was found to be governed by a dominant gene, proposed as Rmd, with the recessive allele, rmd, resulting in susceptibility at all stages.


2016 ◽  
Vol 43 (1) ◽  
pp. 49-51 ◽  
Author(s):  
W.D. Branch ◽  
T.B. Brenneman ◽  
J.P. Noe

ABSTRACT Root-knot nematode (RKN), [Meloidogyne arenaria (Neal) Chitwood race 1] can result in highly significant yield losses in peanut (Arachis hypogaea L.) production. Fortunately, very high levels of RKN nematode resistance have been identified and incorporated from wild species into newly developed peanut cultivars. In 2011-12 at Tifton, GA, a field site was artificially inoculated with M. arenaria race 1. A susceptible cultivar was used to uniformly increase the peanut-specific race 1 nematode population during the summer and fall; whereas, hairy vetch (Vicia villosa Roth) was used for the same purpose each winter as a susceptible cover crop. During 2013 and 2014, space-planted F2 and F3 populations from cross combinations involving A. hypogaea susceptible × resistant parental lines derived from ‘COAN’ were evaluated, respectively. Several past inheritance studies had suggested a single dominant gene, Rma, controlled the resistance. However in this study, the occurrence of a second recessive gene (rma2) was also found to be involved in very high peanut RKN resistance. Inheritance data fit a 13:3 genetic model and confirmed an earlier report for two RKN-resistance genes (Rma1 and rma2) found in TxAG-6 and now COAN.


BIOEDUSCIENCE ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 1-10
Author(s):  
Muhammad Alif Ishak ◽  
Budi Setiadi Daryono

Background: A powdery mildew-resistant cultivar of melon is needed to increase melon yield crops. Meloni is a superior melon cultivar bred through a crossing between ♀ SL-3 and ♂ PI 371795, resulted by the Laboratory of Genetics and Breeding, Faculty of Biology, UGM. This study aimed to determine the level resistance of Meloni to powdery mildew infection and to identify the powdery mildew species that infected Meloni based on morphological characters. Methods: Meloni seeds were germinated and planted in the greenhouse of PIAT UGM. Powdery mildew spores were inoculated into the leaves after ±2 weeks of age. Leaf infected were scored using the gridline every 3 days for 6 weeks. Scoring results were converted to the diseases index score. Furthermore, powdery mildew species was identified using morphological characters. Results: Meloni had a tolerance level of resistance to the powdery mildew infection. Based on the morphological characters with fibrosin bodies, conidia ovoid-shape and the position of the germ tube in the lateral part of the conidia, powdery mildew that infected Meloni was expected as P. xanthii. Conclusions: Meloni can be expected as an alternative to superior melon seeds resistant to pest and disease infections especially powdery mildew.  


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