Registration of Two Double Rust Resistant Germplasms, HA‐R12 and HA‐R13 for Confection Sunflower

Abstract

Two confection sunflower (Helianthus annuus L.) germplasms, HA‐R12 (Reg. No. GP‐333, PI 673104) and HA‐R13 (Reg. No. GP‐334, PI 673105), were developed by the USDA‐ARS, Sunflower and Plant Biology Research Unit, Fargo, ND, in collaboration with the North Dakota Agricultural Experiment Station, and released in July 2014. Sunflower rust (caused by Puccinia helianthi Schwein.) is a major yield‐ and quality‐limiting factor for sunflower production worldwide. Because of the evolution of new rust pathotypes, it is important to combine multiple resistance genes into one sunflower genotype to overcome the newly emerging virulent races. HA‐R12 and HA‐R13 were developed by the pedigree method and DNA marker‐assisted selection. HA‐R12 harbors the rust resistance (R) genes, R2 from MC29 (AUS) and R13a from HA‐R6. HA‐R13 contains R5 from HA‐R2 and R13a from HA‐R6. Marker testing and rust resistance evaluation confirmed that HA‐R12 and HA‐R13 each separately harbors two rust resistance genes in the homozygous condition, with both lines showing high levels of resistance to rust races 336 and 777, a predominant race and one of the most virulent races currently identified in the United States, respectively. HA‐R12 and HA‐R13 will provide urgently needed rust resistance genes that can be incorporated into commercial confection hybrids, providing broad‐spectrum rust resistance.