Mapping components of flour and noodle colour in Australian wheat

Flour and noodle colour influence the value of wheat (Triticum aestivum L.) and are obvious targets for breeders seeking to improve quality, end-produ ct range, and marketability of wheat. The objective of this investigation w as to identify quantitative trait loci (QTLs) associated with flour and noo dle colour traits and with individual components of colour. One hundred and sixty-three doubled haploid lines derived from Sunco x Tas man, white-grai ned, prime hard, and hard wheats adapted to the north-eastern region of Aus tralia were used for the bulk of this study and were supplemented by double d haploid populations derived from CD87 x Katepwa and Cranbrook x Halberd f or comparisons of flour colour. Samples of Sunco x Tasman, together with pa rental lines, were grown at Narrabri, NSW, in 1998 and 1999 and at Roma, Ql d, in 1998 and used for visible light reflectance measurements of flour bri ghtness (CIE L*) and yellowness (CIE b*), and white salted noodle (WSN) and yellow alkaline noodle (YAN) brightness, yellowness, and colour stability. Xanthophyll content and polyphenol oxidase (PPO) activity were measured sp ectrophotometrically. No consistent QTLs were identified for flour L* or initial L* of WSN and YA N. Xanthophyll content was very strongly associated with QTLs located on ch romosomes 3B and 7A and these QTLs also had a major influence on flour b*, WSN b*, and YAN b*. Noodle brightness at 2, 24, and 48 h and the magnitude of change in noodle L* and b* with time were affected by QTLs on 2D, contri buted by Tasman, and, to a lesser degree, 2A. The QTL on 2D was clearly ass ociated with control of grain PPO, an enzyme implicated in darkening of Asi an style noodles. QTLs located on 2B, 4B, and 5B and associated with contro l of grain size or flour protein content also appeared to influence a numbe r of colour traits.