Author: Michael Ray RobinsonPublisher:
ISBN:
Category : Cotton
Languages : en
Pages : 206
Book Description
Identification of Root-knot Nematode Resistance Genes in Day Neutral Converted Race Accessions in Upland Cotton
Author: Michael Ray RobinsonPublisher:
ISBN:
Category : Cotton
Languages : en
Pages : 206
Book Description
Identification of Root-knot Nematode Resistance Loci in Gossypium Hirsutum Using Simple Sequence Repeats
Author: Sonia Y Del RioPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Gossypium hirsutum, upland cotton, is one of the major crops grown in the United States and the world. Upland cotton is cultivated in areas that are ideal breeding grounds for the difficult to manage, southern root-knot nematode (RKN), Meloidogyne incognita. Host plant resistance is the most effective way to control RKN populations. However, resistance used in most breeding programs stems from a few related sources. Novel sources of resistance have been identified but have yet to be introduced into elite breeding lines or genetically studied. The objectives of this study are two-fold. The first is to develop elite germplasm by introgressing RKN resistance from primitive accessions into modern cotton genotypes via backcrossing. The second is to use simple sequence repeats (SSRs) to identify loci associated with RKN resistance in the primitive accessions. The genotypes used will be: 1) inoculated with M. incognita, 2) phenotypically analyzed by measuring the nematode reproduction as eggs per gram of fresh root and host response using a root gall index, 3) genetically evaluated by using SSR markers to detect polymorphisms between the RKN resistant TX accessions and DP90 (susceptible genotype), and 4) analyzed using linkage and mapping software. Elite germplasm that contains: 1) high yield potential and a high level of RKN- resistance or 2) high fiber quality and RKN-resistance was developed by performing two backcrosses based on phenotypic analyses. A third screen is currently underway to ensure the introgression of the RKN resistance genes. Agronomic tests will need to be done before the germplasm is released. Genetic analyses using SSR-based primer sets of the TX accessions did not yield expected results. Of the 508 primers sets tested, only 31 were polymorphic between the TX accessions and DP90. A bulked segregant analysis approach was used to test the 31 primer sets on the resistant and susceptible bulks of the F2 population but no polymorphisms were seen. However, analyses found that the TX accessions were more genetically similar to Mexico Wild Jack Jones than to Clevewilt 6-3-5. More work needs to be done to understand the mechanism of RKN resistance in the TX accessions. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149444
Dissertation Abstracts International
Author: Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 726
Book Description
Upland Cotton and Nematodes: An Analysis of Historical Resistance, Upcoming Threats, and Co-inoculation Effects
Author: Amanda GaudinPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Upland cotton (Gossypium hirsutum ) is an important fiber crop grown throughout the southern United States. Plant-pathogenic nematodes are worm-like animals that feed on the roots of most agronomic crops, including cotton. The southern root-knot nematode (Meloidogyne incognita, RKN) and the reniform nematode (Rotylenchulus reniformis, RN) cause significant yield losses in cotton every year. Current sources of resistance are effective but limited, therefore historical screenings of cotton accessions were revisited in search for novel resistance sources. None were identified but many of the screened accessions possessed markers of known root-knot nematode and reniform nematode resistance. The emerging guava root-knot nematode (Meloidogyne enterolobii, GRKN) is a risk for upland cotton production, and identifying host plant resistance would greatly reduce the yield losses for growers. Assays were conducted on the currently available RN and RKN resistance sources inoculated with GRKN. No known nematode resistance gene suppressed GRKN infection, indicating that work must be done to protect crops from the eventual discovery of GRKN in Mississippi fields. Using the same resistance sources, tests were conducted to determine if the currently available resistances to RKN and RN offer any suppression of secondary infection of non-target nematode species for resistance. This is referred to as systemic acquired resistance, which is the induction of non-specific plant defense. Assays found that early inoculation with the nematode targeted by resistance did not effect infection by a secondary nematode species.
Cotton Germplasm
Author: Jack C. McCartyPublisher:
ISBN:
Category : Cotton
Languages : en
Pages : 4
Book Description
Agronomy News
Author: Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 850
Book Description
Sept.-Oct. issue includes list of theses and dissertations for U.S. and Canadian graduate degrees granted in crop science, soil science, and agronomic science during the previous academic year.
Indices of Resistance to Root-knot Nematodes for Primitive Race Stocks of Upland Cotton
Author: Raymond L. ShepherdPublisher:
ISBN:
Category : Cotton
Languages : en
Pages : 8
Book Description
Plants Reported Resistant Or Tolerant to Root Knot Nematode Infestation
Author: Jocelyn TylerPublisher:
ISBN:
Category : Nematode diseases of plants
Languages : en
Pages : 98
Book Description
Author: R. L. Shepherd
Author: Limei He