GEORGIA / FLORIDA
UNIVERSITY OF GEORGIA
Department of Agronomy, Griffin, GA 30212, USA.
J.W. Johnson, J. W. Buck, G.D. Buntin, and Z. Chen.
The 2006 Georgia winter wheat crop was grown on about 280,000 planted acres. Yields of wheat grown by top producers were around 6,000 kg/ha on cultivars resistant to stripe rust. Average yield for the state was 3,200 kg/ha. The growing season was characterized by mild weather and very dry conditions during the winter and spring. A lack of vernalization was a problem for late maturing varieties. Only 60% of the average rainfall occurred during the spring. A severe epidemic of stripe rust was observed in Georgia and the lower southeastern U.S.
GA 951395-3A31 (AGS 2031) is a medium-maturing, white-chaffed, medium-height line derived from the cross 'GA 87110 / VA93-52-55 // GA 88151'. With a maturity is similar to that of AGS 2000, it is an average of 1.0 day later in Georgia. GA 951395.3A31 is susceptible to current biotypes of Hessian fly in Georgia and is resistant to races of leaf rust and stripe rust due to adult plant resistance and has adult plant resistance to powdery mildew. The cultivar also is resistant to soilborne mosaic virus.
GA 951395-3E25 (USG 3295) is a medium-maturing, white-chaffed, medium-height line derived from the cross 'GA 87110 / VA93-52-55 // GA 88151'. At maturity, it is similar to AGS 2000 with an average of 2.0 days later in Georgia. GA 951395-3E25 is susceptible to current biotypes of Hessian fly in Georgia and is resistant to races of leaf rust and stripe rust due to adult-plant resistance and has adult-plant resistance to powdery mildew. The cultivar also is resistant to soilborne mosaic virus.
GA 96229-3A41 (SS8641) is a medium-maturing, white-chaffed, medium-tall line derived from the cross 'GA 881130 / 2* GA 881582'. The pedigree of GA 881130 is 'KSH8998 / FR 81-10 // Gore'. KSH8998 was developed from the cross of a hard wheat with Ae. tauschii to transfer Hessian fly resistance gene H13. FR 81-10 was selected because of its resistance to leaf rust (Lr37 and Yr17) from the cross 'Novisad 138 /4/ (4) Ae. ventricosa / T. persicum /2/ Marve*3 /3/Moisson'. GA 96229-3A41 has maturity is similar to that of AGS 2000 with an average of 1 day later in Georgia. The cultivar is resistant to current biotypes (B and E) of Hessian fly in Georgia and is resistant to races of powdery mildew, leaf rust, and stripe rust in Georgia. GA 96229-3A41 also is resistant to wheat soil-borne mosaic virus. GA 96229-3A41 has an excellent combination of resistance to diseases (powdery mildew, stripe rust, leaf rust, and soil-borne mosaic virus).
In the southeast region of the U.S., resistance to FHB in local adaptive soft red winter wheat is limited. Introduction of resistant genes from exotic sources with QTL located at 3BS and 5AS could enhance the resistance of local adaptive germ plasm. Thirty-six elite breeding lines from breeding programs in the southeast region including eight from Arkansas, four from North Carolina, six from Virginia, and six from the University of Georgia were evaluated with Ernie and Coker 9835, as resistant and susceptible controls, respectively, under misted conditions at the Griffin Campus, Georgia. Eight lines showed similar level of severity as the resistant control, and 26 lines were significantly more severe than the resistant check, Ernie. A Georgia line, GA991109, from a cross with Ernie showed better resistance than Ernie. A Virginia line, VA05W-500, from a cross 'Roane / PIO 2684 // OH 552' showed the best and consistent resistance among all three replications in 36 lines. VA05W-500 showed a significantly higher level of resistance than other lines, including the resistant control. Many crosses have been made using Sumai 3 or its derivatives as FHB-resistance donors. However, FHB resistance could be enhanced significantly by combining the native resistance in soft red winter wheat and reduced the negative yield dragging associate with crosses including exotic of Sumai 3 or its derivatives. Studies on the native resistance for FHB is needed for more efficient accumulation of native resistance into local adaptive cultivars.
Stripe rust was very severe in 2006. We identified the effective genes as Yr17 (GA96229-3A41) and Yr18 in combination with other genes (PIO 26R61), adult-plant resistance in GA951395-3A31 and GA951395-3E25). Yr5, Yr15, and Yr27 also provided effective resistance.