2012 Annual Report
1a.Objectives (from AD-416):
Introduce spring and winter wheat germplasm with potential stripe rust resistance
from CIMMYT/Mexico and CIMMYT/Turkey and clear through quarantine
regulations. Evaluate introduced germplasm for stripe rust resistance, distribute introduced stripe rust materials to interested wheat breeders, and make crosses to transfer stripe rust resistance from introduced materials into adapted winter wheat cultivars.
1b.Approach (from AD-416):
Several new international nurseries from CIMMYT/Mexico and from the GOT/CIMMYT/ICARDA Program in Turkey will be introduced and grown under quarantine regulations in the greenhouse. Previously introduced germplasm will be screened in the regional disease nursery in south Texas, and the winter types also will be evaluated in Oklahoma. All populations derived from crosses for stripe rust resistance will be screened in south Texas and in Oklahoma. Introduced materials and F3 populations with good stripe rust resistance will be made available to interested breeders from the region. CIMMYT materials will be distributed under their MTA.
During the 2011-2012 crop cycle, the Wheat Germplasm Development program at OSU continued its efforts to incorporate adult plant type resistance (APR) to stripe rust into adapted winter wheat germplasm. Crosses made for stripe rust resistance represent approximately 35% of the total crosses made in the program, and more than 1300 crosses have been made during the project. The majority of the crosses involve spring wheat materials from CIMMYT/Mexico with adult plant resistance to stripe rust based on multiple race non-specific genes, but an increased number of crosses are being made to stripe rust resistant winter wheat materials from the Government of Turkey/CIMMYT/ICARDA program. The ultimate objective of this program is to provide producers with a more durable (longer lasting) type of stripe rust resistance. Five international spring wheat nurseries from CIMMYT, containing more than 800 advanced lines were grown in the south Texas disease nursery during the 2012 crop cycle (Table 1). Additionally, three winter wheat nurseries from Turkey, containing 300 advanced winter wheat lines were evaluated in south Texas and in Oklahoma.
Moderate stripe rust was present in Oklahoma and throughout the region in 2012, and a new race with virulence on many of the newly released varieties appeared for the first time. This is the second change in virulence in the last 3 years; Yr 17 virulence appeared for the first time in 2010. The appearance of these new virulences dramatically demonstrates the need for more durable types of resistance based on race non-specific APR genes or based on multiple race-specific genes. Most of the materials from the Turkey/CIMMYT/ICARDA program had good resistance to the new stripe rust virulence, but these materials are generally susceptible to leaf rust and mildew. However, numerous selections were made and these new materials will be used more extensively as parents in future crossing. These selected materials have been distributed to various breeding programs in the region.
The 19th FAWWON-Irrigated and the 19th FAWWON-Semi-Arid Nurseries were evaluated in Oklahoma and in the south Texas nursery. These nurseries also contained materials from CIMMYT’s winter wheat program in Turkey that have been selected for stripe rust resistance, plus advanced materials from various countries in Eastern Europe, Russia, Ukraine, and from countries in western and southern Asia. Most of these materials should have good levels of stripe rust resistance, and many of the material have resistance to leaf rust and mildew.
Without a doubt, the nurseries currently being distributed, as well as those that are just being introduced into the program, contain numerous and diverse sources of resistance to stripe rust that will help us achieve our ultimate goal—high yielding, stripe rust resistant cultivars for wheat producers throughout the nation.