Abstract
The effects on barley starch and grain properties of four starch synthesis mutations were studied during the introgression of the mutations from diverse backgrounds into an elite variety. The lys5f (ADPglucose transporter), wax (granule-bound starch synthase), isa1 (debranching enzyme isoamylase 1) and sex6 (starch synthase IIa) mutations were introgressed into NFC Tipple to give mutant and wild-type BC2F4 families with different genomic contributions of the donor parent. Comparison of starch and grain properties between the donor parents, the BC2F4 families and NFC Tipple allowed the effects of the mutations to be distinguished from genetic background effects. The wax and sex6 mutations had marked effects on starch properties regardless of genetic background. The sex6 mutation conditioned low grain weight and starch content, but the wax mutation did not. The lys5 mutation conditioned low grain weight and starch content, but exceptionally high β-glucan contents. The isa1 mutation promotes synthesis of soluble α-glucan (phytoglycogen). Its introgression into NFC Tipple increased grain weight and total α-glucan content relative to the donor parent, but reduced the ratio of phytoglycogen to starch. This study shows that introgression of mutations into a common, commercial background provides new insights that could not be gained from the donor parent.
Highlights
The aim of this work was to characterise variation for starch properties in barley, and to provide new barley germplasm for evaluation of the commercial potential of this variation
Grain and starch properties were analysed on samples harvested from NFC Tipple, the original mutant accessions, and BC2F4 recombinant lines developed from crosses between NFC Tipple and the four donor parents
Donor parents were in several cases markedly different from the wild-type control, grains from low-donor families almost all closely resembled those of the wild-type control
Summary
The aim of this work was to characterise variation for starch properties in barley, and to provide new barley germplasm for evaluation of the commercial potential of this variation. Industry exploits naturally-occurring variation for starch properties within and between starch crops. Starch from the waxy mutant of maize gelatinises to form clear pastes with specific applications in the food industry, and “high-amylose” maize starch (from the amylose-extender mutant) is valued for its film-forming properties (Jobling, 2004). Naturally-occurring variation in starch properties influences the quality of foods made from starch crops. The waxy mutant of rice has eating properties that are prized in East Asia, and flour from high-amylose maize gives baked products with low glycaemic indices because of the resistance of the starch to digestion in the gut (Behall and Hallfrisch, 2002; Nugent, 2005)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have