Location: Wheat Health, Genetics, and Quality Research
Project Number: 2090-21000-039-003-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 28, 2019
End Date: Aug 27, 2024
Objective:
The ARS-WHEAT HEALTH, GENETICS AND QUALITY RESEARCH UNIT and WASHINGTON STATE UNIVERSITY are collaborating to generate doubled haploids and conduct ‘speed’ breeding in wheat.
Specific Objectives are to:
1. Generate up to 1,000 doubled haploid breeding lines from the club wheat program per year of the agreement.
2. Advance up to 150 segregating populations using speed breeding methods per year of the agreement.
Approach:
Doubled haploids of wheat will be developed using the Maize hybridization technique. The ARS will supply the cooperator with F1 or BC1 seeds from crosses among wheat germplasm. Briefly, the ARS will emasculate the wheat flower prior to anthesis and pollinate with fresh maize pollen. The COOPERATOR will spray the developing embryo with a dilute growth regulator and bagged to prevent contamination. Fourteen to sixteen days after pollination, the COOPERATOR will excise embryos excised under sterile conditions and place them on MS media until they form roots and germinate. The COOPERATOR will treat young plantlets with colchicine to cause the chromosome numbers to double. The COOPERATOR will vernalize the putative doubled haploids. ARS will then grow them in the WSU plant growth facility. Seed that develops on fertile tillers is a doubled haploid and is returned to the breeding program.
For speed breeding, the ARS will develop segregating populations. The COOPERATOR will advance them to the F2 or BC1-F1 generation as follows: The population is germinated in germination boxes and vernalized for 6 weeks at 4oC under a 16-hour daylength. After vernalization, the germination paper is split and the paper with the adhering seedlings is planted into one-gallon pots in potting soil and placed into the greenhouse at 25oC and a 16-hour daylength. The crowding the pots ensures that only a single small head is produced from each plant. The plants are dried down as soon as kernels develop, harvested at physiological maturity and dried. The cycle is repeated for one or two more generations. The ARS and the COOPERATOR will continue to evaluate some environmental parameters such as the quality of the light, the duration of the light, the optimal temperature for plant growth and the use of various plant growth regulators to speed time to flowering to see which are best to use for speed breeding.
