scholarly journals A Rice Black-Streaked Dwarf Virus Replication Curve Model to Evaluate Maize Rough Dwarf Disease Resistance

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 868-873 ◽  
Author(s):  
Han Xiaohua ◽  
Chen Tingmu ◽  
Yue Runqing ◽  
Guo Shulei ◽  
Xu Mengmeng ◽  
...  
Keyword(s):  
Virus Transmission ◽  
Model Fit ◽  
Dwarf Virus ◽  
Resistant Variety ◽  
Maize Rough Dwarf Disease ◽  
Maize Germplasm ◽  
Maize Varieties ◽  
Curve Model ◽  
Transmission Period ◽  
Dwarf Disease

Resistance to maize rough dwarf disease (MRDD), a major cause of crop losses, depends on external conditions such as the virus transmission period and the rate of viruliferous small brown planthoppers, Laodelphax striatellus. The precise identification of MRDD contributes to the utilization of resistant germplasm and the cloning of resistant genes. In this study, eight maize varieties were artificially inoculated in a greenhouse with viruliferous planthoppers. The viral titers in maize seedlings were detected by quantitative fluorescence RT-PCR, and the viral replication curves were analyzed by regression. A logistic model fit the Rice black-streaked dwarf virus (RBSDV) replication data for five susceptible varieties well, whereas a linear model fit the data for three resistant varieties. Among the five susceptible varieties, the time points with the maximum replication rates (tIP) of the highly susceptible Ye478 and XH6 were significantly earlier than those of the three susceptible varieties, Mo17, Zheng58, and Zhengdan958. P138, the most highly resistant variety, had the lowest slope of the best fit line, followed by moderately resistant Chang7-2 and Dan 340. The RBSDV replication curve model developed in this study can accurately identify the resistance of maize germplasm to MRDD at the molecular level. Our results also suggested that tIP and the slope of the RBSDV replication curve can be considered new criteria to evaluate maize resistance to MRDD.

scholarly journals Resistance Response of Maize Germplasm to Downy Mildew [Peronosclerospora philipinensis]

2018 ◽  
Vol 24 (1) ◽  
pp. 43
Author(s):  
Syahrir Pakki ◽  
Mappaganggang Mappaganggang
Keyword(s):  
Downy Mildew ◽  
Block Design ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Average Intensity ◽  
Standard Score ◽  
Resistance Response ◽  
Maize Germplasm ◽  
Randomized Block Design ◽  
Moderately Resistant

<p>Two experiments to study responses of resistance of maize germplasm to downy mildew (Peronosclerospora philipinensis) have been conducted. Both experiments were arranged in randomized block design with two replication. The treatments in each experiment (2014 and 2016) were 70 maize accessions. The accessions were planted in planting distant of 75 cm × 20 cm, in 5 m rows, resulting in 20 plants per row. In every 10 rows, two check varieties were planted, i.e. one susceptible and one resistant variety. Ten days prior to planting, the soil was fertilized with mixed fertilizers consisted of urea, ZA, SP36, and KCl at a dose of 100, 100, 100, and 100 kg/ha, respectively. Fertilization II and III was given at 30 days after planting, and 45 days after planting with a dose of 100 kg urea/ha. As a source of inoculum downy mildew, around the repeated plot was planted with varieties Anoman variety (susceptible variety) that was inoculated with a suspension of downy mildew pathogen. Observation was conducted at 25, 35, and 55 days after planting, with the standard score of resistant to downy mildew, followed: 0–10% = resistant, 11–25% = moderately resistant, 26–50% = moderately susceptible, &gt;50% = susceptible. The result of the experiments showed that there were 5 accessions resistant to downy mildew (P. philipinensis), i.e. CML 440×MR4-9-30-3, 664, 60, 572, and 554 with the intensity of downy mildew infection ranged from 5 to 10%. Twelve other accessions were classified as moderately resistant, i.e. CML 440×MR4-9-98-2, 440×MR4-9-98-4 CML, CML 440×MR4-9-124-1, 66, 71, 319, 108, 73, 48, 105, 554, and 682 with intensity of infection ranged from 13 to 25%. At the same experiments, the average intensity of downy mildew infection on susceptible check varieties reached 100 percent.</p>

scholarly journals Identification and fine-mapping of a QTL, qMrdd1, that confers recessive resistance to maize rough dwarf disease

2013 ◽  
Vol 13 (1) ◽  
pp. 145 ◽  
Author(s):  
Yongfu Tao ◽  
Qingcai Liu ◽  
Honghong Wang ◽  
Yanjun Zhang ◽  
Xinyi Huang ◽  
...  
Keyword(s):  
Fine Mapping ◽  
Recessive Resistance ◽  
Maize Rough Dwarf Disease ◽  
Dwarf Disease

scholarly journals Breeding Potential of Maize Germplasm Line GEMS-0067 for High Amylose Proportion

2021 ◽  
Author(s):  
Nan Han ◽  
Wanchen Li ◽  
Chuanxiao Xie ◽  
Fengling Fu
Keyword(s):  
Starch Content ◽  
Degree Of Polymerization ◽  
Breeding Potential ◽  
Maize Germplasm ◽  
Maize Varieties ◽  
Germplasm Line ◽  
Recessive Mutant ◽  
High Amylose ◽  
Filling Characteristics ◽  
Starch Industry

Maize varieties with high amylose proportion are more valuable for starch industry. The SBEⅡb gene encodes one of the starch branching isozymes (SBEⅠ, SBEⅡa, and SBEⅡb). Its recessive mutant amylose-extender (ae/sbe2b) decreases the total activities of SBEs and increases amylose proportion up to 60%. Here, the breeding potential of introduced germplasm line GEMS-0067 was evaluated by genotyping and phenotyping. The deletion of the ninth exon of the SBEⅡb gene, high amylose proportion, and the typical irregular granules suggested that this germplasm line was derived from the same resource of high amylose line AE11. The gelatinization and thermal properties, and degree of polymerization of starch chain showed its advantages used for high amylose breeding. However, the negative correlation between amylose proportion and starch content, as well as ker-nel filling characteristics should be overcome during breeding process.

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