Phenotypic and Genotypic Analyses of Maize Inbreds Selected for Improved Resistance to Stalk Tunneling by the European Corn Borer (Ostrinia Nubilalis (Hübner)) PDF Download
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Author: Daniel Pablo Donadio Publisher: ISBN: Category : Languages : en Pages : 258
Book Description
The European corn borer (ECB) significantly affects the production of maize in temperate regions. Second-generation ECB larvae tunnel into the stalks leading to reduced plant growth and grain yield. Several inbreds such as B52, DE811, and B86 have been identified as resistant to tunneling. However, selection for native resistance is difficult because the genetic mechanisms controlling the trait are unknown. Backcross (BC) lines are derived from B73/B52 and B73/DE811 populations were developed and selected for reduced tunneling by ECB. Phenotypic analysis of the BC lines was performed to assess their degree of resistance with respect to the parental lines. Genotypic analysis of the BC lines was accomplished by use of simple sequence repeat (SSR) primer pairs. This analysis included the investigation of the origin of chromosomal segments, estimation of parental contribution, construction of graphical genotypes, detection of loci associated with resistance and their comparison with quantitative trait loci (QTL) reported by other researchers. For the B73/B52 population, 19 of the 34 BC lines were as resistant as B52 and 1 BC line was as susceptible as B73. No correlation was found between stalk tunneling and either plant height or anthesis date. The proportion of B52 alleles in the genome of the BC lines was 2.9 to 5.2 times greater than expected assuming absence of selection and linkage. Nineteen loci could be associated with resistance. However, only 5 of them coincided with QTLs reported in other studies. For B73/DE811 population, 1 of the 6 BC lines was as resistant as DE811. Percentage of damage caused by ECB and anthesis were significantly correlated ( -0.74). The proportion of DE811 alleles was 2.3 to 8.8 times greater than expected under the cited assumptions.
Author: Daniel Pablo Donadio Publisher: ISBN: Category : Languages : en Pages : 258
Book Description
The European corn borer (ECB) significantly affects the production of maize in temperate regions. Second-generation ECB larvae tunnel into the stalks leading to reduced plant growth and grain yield. Several inbreds such as B52, DE811, and B86 have been identified as resistant to tunneling. However, selection for native resistance is difficult because the genetic mechanisms controlling the trait are unknown. Backcross (BC) lines are derived from B73/B52 and B73/DE811 populations were developed and selected for reduced tunneling by ECB. Phenotypic analysis of the BC lines was performed to assess their degree of resistance with respect to the parental lines. Genotypic analysis of the BC lines was accomplished by use of simple sequence repeat (SSR) primer pairs. This analysis included the investigation of the origin of chromosomal segments, estimation of parental contribution, construction of graphical genotypes, detection of loci associated with resistance and their comparison with quantitative trait loci (QTL) reported by other researchers. For the B73/B52 population, 19 of the 34 BC lines were as resistant as B52 and 1 BC line was as susceptible as B73. No correlation was found between stalk tunneling and either plant height or anthesis date. The proportion of B52 alleles in the genome of the BC lines was 2.9 to 5.2 times greater than expected assuming absence of selection and linkage. Nineteen loci could be associated with resistance. However, only 5 of them coincided with QTLs reported in other studies. For B73/DE811 population, 1 of the 6 BC lines was as resistant as DE811. Percentage of damage caused by ECB and anthesis were significantly correlated ( -0.74). The proportion of DE811 alleles was 2.3 to 8.8 times greater than expected under the cited assumptions.
Author: Chaba Jampatong Publisher: ISBN: Category : Corn Languages : en Pages : 160
Book Description
European corn borer (ECB), Ostrinia nubilalis Hübner, family Crambidae, order Lepidoptera, is a serious insect pest of maize (Zea mays L.) in the United States. Losses to farmers resulting from ECB damage and control costs exceed $1 billion each year. An understanding of the genetic basis for ECB resistance should increase the efficiency of breeding for insect resistant varieties. The objectives of this study were to determine the number, genomic positions, and genetic effects of quantitative trait loci (QTL) conferring resistance to the first- and second-generation of European corn borer (1ECB, 2ECB), and to observe QTL × environment interactions. The study included 244 F 2-3 families derived from the cross of B73 (susceptible) × Mo47 (resistant). Evaluating resistance against 1ECB, plants were manually infested at the eight- to ten-leaf stage of plant development. Leaf feeding damage was assessed three weeks after infestation with a visual rating scale. Evaluation for resistance to 2ECB involved manually infesting at anthesis stage of plant development. Approximately seven weeks later, stalks were split lengthwise and number and the length of tunnels visually estimated in inches. Plant height and rind penetrometer resistance were measured two weeks after flowering. Quantitative trait loci analyses for individual environments and combined across three environments were performed by composite interval mapping using QTL Cartographer. For 1ECB leaf feeding, nine QTLs were identified on chromosomes 1(three QTLs), 2, 4 (two QTLs), 5, 6, and 8. Seven QTLs for resistance to 2ECB tunnel length were found on chromosomes 2, 5 (two QTLS), 6 (two QTLs), 8, and 9. Twelve QTLs for resistance to 2ECB tunnel length adjusted for plant height were identified on chromosomes 1 (two QTLs), 2, 3 (two QTLs), 5, 6 (three QTLs), 8, 9, and 10. In addition, QTLs were identified for tunnel number (16 QTLS), plant height (11 QTLs) and rind penetrometer resistance (nine QTLs). In this experiment, a total of 47 QTLs for all traits were mapped in three individual environments and combined over environments. Nine (19%) QTLs were expressed in all three environments and combined, 17 (36%) were expressed in two environments and combined, and 21 (45%) were expressed only in single environment and combined. Inconsistency of QTLs across environments suggested need for breeders awareness when selecting markers linked to QTLs for marker-assisted selection (MAS). Further study on consistency of QTLs across populations is needed before applied breeding programs can fully utilized QTL information.
Author: Sherry Ann Flint-Garcia Publisher: ISBN: Category : Corn Languages : en Pages : 300
Book Description
Stalk lodging in maize (Zea mays L.) causes losses estimated to range from 5 to 20% annually in the United States. Selection for rind penetrometer resistance (RPR) has proven useful in enhancing germplasm for stalk strength, and therefore improving stalk lodging resistance. We conducted quantitative trait locus (QTL) analysis for RPR in three F 2:3 populations. Populations were constructed by using combinations of lines selected for high RPR, low RPR, low stalk crushing strength, and inbred line Mo47. Eight, ten, and eight single-effect QTL, and four, two, and zero epistatic interactions were detected for RPR in the three populations, respectively. These data clearly indicate the complex nature of stalk strength. Multi-locus models, including significant single-effect QTL and epistatic interactions, accounted for 33.4%, 44.7%, and 48.4% of the total phenotypic variation. Similar analyses were conducted for plant height (PH), ear height (EH), and resistance to second-generation European corn borer (2-ECB), yielding results similar to those of previous studies. The correlation between RPR and EH is of interest in understanding response to selection for RPR. Has selection for high RPR resulted primarily in increased stalk strength per se and coincidentally lower ear heights, or has selection for high RPR resulted in lower ear heights and subsequently higher stalk strength? To determine the genetic relationship between RPR and the correlated trait EH, QTL were characterized and compared in each of the three F 2.3 populations for RPR, EH, and RPR adjusted for EH (RadjE). Adjusting RPR for EH caused 11 of the 26 original RPR QTL to lose their significance. However, the majority, 15 of 26, of the original RPR QTL remained significant as QTL for RadjE. These results demonstrated that although EH had a significant effect on RPR as reflected in the negative correlation, QTL analysis can be used to separate genetic effects for RPR per se from genetic effects caused by the correlated trait. A final objective of this study was to compare the efficiency of phenotypic selection vs. marker-assisted selection (MAS) for RPR and 2-ECB. Marker-assisted selection for high and low RPR was effective in all three populations. Phenotypic selection for both high and low RPR in Populations 1 and 2 was more effective than MAS. However, in Population 3, MAS for high RPR using QTL from Population 3 was more effective than phenotypic selection, and using QTL from Population 4 was just as effective for high RPR as phenotypic selection. These results, therefore, validate the locations and effects of QTL identified for RPR.
Author: Craig Arthur Abel Publisher: ISBN: Category : Languages : en Pages : 358
Book Description
Eleven accessions of Peruvian maize were evaluated for mechanisms of resistance to leaf feeding by European corn borer, Ostrinia nubilalis (Hubner). Antibiosis was identified as one mechanism of resistance that operates at a level equivalent to Cl31A which is a maize inbred line containing high levels of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), thus having strong antixenotic and antibiotic properties towards leaf feeding by European corn borer. Antixenosis may be another mechanism of resistance operating in the Peruvian maize but at a level lower than Cl31A. The 11 Peruvian maize accessions were used as donor parents in a backcross plant breeding program designed to introgress the European corn borer resistance trait into two elite U.S. Corn Belt adapted inbred lines. Resistance to European corn borer leaf feeding and sheath and collar feeding was recovered in the Fl indicating dominant genetic control.
Author: Daniel Pablo Donadio
Author: Daniel Pablo Donadio
Author: Chaba Jampatong
Author: 
Author: Sherry Ann Flint-Garcia
Author: Clark Waller Jennings
Author: Christine Papst
Author: Iowa State University
Author: Ralph Kreps
Author: Bradley R. Engel
Author: Craig Arthur Abel