Registration of Durum Wheat Germplasm Lines with Combined Mutations inSBEIIa andSBEIIbGenes Conferring Increased Amylose and Resistant Starch.
Durum wheat [Triticum turgidumL. subsp.durum(Desf.) Husn.], used in pasta, couscous, and flatbread production, is an important source of starch food products worldwide. The amylose portion of the starch forms resistant starch complexes that resist digestion and contribute to dietary fiber. Increasing the amount of amylose and resistant starch in wheat by mutating theSTARCH BRANCHING ENZYME II(SBEII) genes has potential to provide human health benefits. Ethyl methane sulfonate mutations in the linkedSBEIIaandSBEIIbparalogs were combined on chromosomes 2A (SBEIIa/b-A; Reg. No. GP-968, PI 670159), 2B (SBEIIa/b-B; Reg. No. GP-970, PI 670161), and on both chromosomes (SBEIIa/b-AB; Reg. No. GP-969, PI 670160) in the tetraploid wheat cultivar Kronos, a semidwarf durum wheat cultivar that has high yield potential and excellent pasta quality. These three double and quadrupleSBEII-mutant lines were compared with a control sib line with noSBEIImutations in two field locations in California. TheSBEIIa/b-AB line with four mutations showed dramatic increases in amylose (average 66%) and resistant starch (average 753%) relative to the control. However, theSBEIIa/b-AB line also showed an average 7% decrease in total starch and an 8% decrease in kernel weight. The release by the University of California-Davis of the durum wheat germplasm combining fourSBEIIaandSBEIIbmutations will accelerate the deployment of these mutations in durum wheat breeding programs and the development of durum wheat varieties with increased resistant starch.
Dep. of Plant Sciences, Univ. of California, Davis, CA 95616; J. Dubcovsky, Howard Hughes Medical Institute, Chevy Chase, MD 20815.
Brittany
B
Hazard
Dep. of Plant Sciences, Univ. of California, Davis, CA 95616; J. Dubcovsky, Howard Hughes Medical Institute, Chevy Chase, MD 20815.
Xiaoqin
X
Zhang
Dep. of Plant Sciences, Univ. of California, Davis, CA 95616; J. Dubcovsky, Howard Hughes Medical Institute, Chevy Chase, MD 20815.
Mahmoudreza
M
Naemeh
Dep. of Plant Sciences, Univ. of California, Davis, CA 95616; J. Dubcovsky, Howard Hughes Medical Institute, Chevy Chase, MD 20815.
Jorge
J
Dubcovsky