Plant Sciences


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Breeding Methods

Several breeding methods are available to plant breeders for germplasm improvement, such as the pedigree method, bulk method, single seed descent, backcross method, and recurrent selection. The North Dakota breeding program primarily uses a modified pedigree program and, to a lesser degree, backcross, single seed descent, recurrent selection and doubled haploid breeding methodologies.

Modified Pedigree Method

A modified pedigree breeding method is used to evaluate ~225 to 275 segregating populations each year. The modified pedigree breeding method involves the evaluation and selection of parents and hybridization to provide useful gene recombinations.

Approximately 75% of the crosses made are single crosses involving only elite adapted parents. The remaining crosses involve one parent that may be considered "exotic," but possesses desirable genes. In this case, three-way crosses are used where the exotic parent's genetic contribution is one-third and the other two parents are elite adapted lines or cultivars. All crossing blocks and F1 generation materials are grown in the greenhouse in Fargo, ND. Individual plants are selected for agronomic traits, glume color (associated with gluten strength), and disease resistance from space-planted F2 populations grown in the field at Fargo and Langdon, ND. These selected plants are further tested for advance and possible variety release.  From the initial cross to variety release (10 to 12 years) the experimental lines are extensively evaluated for their agronomic, disease resistance, milling, and end-use quality traits.


Double Haploid Breeding

On average, 10 to 12 years are required to develop durum cultivars using the modified pedigree method. The use of doubled haploids in a breeding program is important in genetic studies and when rapid cultivar development is required.  Completely homozygous and homogenous inbred lines can be developed in a single generation using the doubled haploid system.  On average, we produce 300 to 400 doubled haploids every year using maize (Zea mays L.) as the pollen donor.  Most of the doubled haploid populations are generated for genetic studies of various agronomic and end-use quality traits and to develop parents or cultivars resistant to Fusarium head blight.


Marker-assisted Breeding

Interest in applying molecular markers to various crop breeding endeavors has gained popularity. Three potential uses of molecular markers to assist crop breeding: 1) to assess the amount of genetic variation in a breeding gene pool, 2) to select lines based on presence of markers, and 3) to reduce undesirable linkage drag when introgressing genes from unadapted germplasm. The genetic variability in the breeding program was estimated using molecular markers.  Marker-assisted selection for traits such as grain protein concentration and disease resistance is being used in the breeding program to enhance cultivar development. Marker-assisted selection also helps to reduce the linkage drag when using the unadapted germplasm such T. dicoccoides and the Fusarium head blight resistant source Sumai 3.

Mapping of Triticum dicoccoides 3 A

marker assisted graph

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