DEVELOPMENT AND CHARACTERIZATION OF GENETIC RESOURCES FOR AGRONOMIC AND QUALITY TRAITS USING GENOMIC TOOLS
Title: Applied genetics: Speeding the development of improved varieties by developing breeding tools and genetic knowledge
Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: June 3, 2011
Publication Date: June 28, 2011
Citation: Pinson, S.R., Tabien, R., Tarpley, L. 2011. Applied genetics: Speeding the development of improved varieties by developing breeding tools and genetic knowledge. Texas Rice Special Section, Highlighting Research in 2011. p. I-II.
Geneticists improve the breeders ability to create new, improved varieties by finding genes, making the genes more available to breeders by moving them into improved germplasm, and devising improved selection techniques, whether based on visual trait evaluations or linkage between genes and molecular markers.
The USDA-ARS Rice Research Unit in Beaumont, TX, conducts genetic research to help breeders improve available rice varieties for the following traits. Early Tillering Enhances Yield Potential Value: Early tillering "locks-in" yield potential before seedling stresses, such as root-pruning by water weevils and reduced tiller production. Tillers also help shade out weeds. Improved Selection Technique – Marker Assisted Selection: We evaluated seedling tiller numbers within two gene-mapping populations and found markers linked to 7 genes. One gene already contained in most U.S. varieties, plus 6 genes found in foreign rice. Breeders can use the linked markers to select for the tillering genes to incorporate them into U.S. varieties. Making Genes More Available to Breeders: Six of the tillering genes were first found in the Chinese variety 'TeQing', where the desired genes are unfortunately connected with undesirable traits such as tall height and late heading time. After several generations of backcrossing, progeny lines were created that had the US-adapted genetic background and contained the desired tillering genes. These lines can be used to introduce just the desired tillering genes from TeQing into their US variety improvement programs.
Putting More Nutrition Into Every Bowl of Rice: Value: Consumers pay more for food products fortified with important minerals, such as calcium-fortified orange juice, or vitamin water. Rice is a naturally healthy food, but more could be sold if it could be marketed as "Naturally Fortified". We grew 1,600 foreign and US rice accessions at Beaumont and sent seed to a cooperator at Purdue University who used an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) to analyze the rice samples for their concentration of 16 elements, namely magnesium, phosphorus, potassium, sulfur, calcium, manganese, iron, cobalt, nickel, copper, zinc, rubidium, strontium, molybdenum, arsenic, and cadmium. A set of 50 rice lines selected for their desirable content of one or more elements was identified, and studies to identify the genes and physiological attributes that underlie their improved nutritional value are now underway. Current investigations are asking if the increased grain mineral content is due to increased root uptake, increased temporary storage in leaves and other plant tissues, or a combination of the two. Segregating cross-progeny will be grown in fields in 2011 to support gene-tagging studies.