Effect of Grain Hardness in Hexaploid Wheat (Triticum aestivum L.) Quality Parameters

LETICIA MIR; LEONARDO VANZETTI; CARLOS BAINOTTI; BELEN CONDE; BEATRIZ MASIERO; MARCELO HELGUERA; GABRIELA TERESA PÉREZ; MARTHA CUNIBERTI

Beijing

Conferencia; 14th ICC Cereal and Bread Congress; 2012

ICC

The wheat market provides a classification of hexaploid wheat (Triticum eastivum) based on the endosperm texture and gluten strength that determines their potential industrial applications. These factors are under genetic control and can be manipulated through breeding. In the definition of the grain texture puroindolines (PIN) play a fundamental role. These proteins are encoded by Pina-D1 and Pinb-D1 genes that are linked to the Hardness locus (Ha). PINs mutations are found in all hard wheats being the most frequent a total deletion of PINA (allele Pina-D1b) or a glycine-to-serine change associated with hard texture in PINB (allele Pinb-D1b). Soft wheats posses the normal allele combination Pina-D1a-Pinb-D1a. In the definition of gluten strength, the most relevant proteins associated are the high molecular weight glutenins (HMWGs) subunits codified by Glu-A1, Glu-B1 and Glu-D1 loci. Different combinations of HMWGs subunitis will produce gluten with higher or lower strength. Wheat qualities most required by industry are: hard wheat for breadmaking, soft wheat for cookies, crackers and cake, durum wheat for pasta and partial ?waxy? for ?noodles?. The aim of this study was to evaluate the effect of grain texture in quality parameters that define different end uses. BC3F4 soft and hard lines were developed using two contrasting genetic backgrounds: (1) the hard wheat cultivar Buck Poncho with a strong gluten (HMWGs 2* / 7oe+8* / 5+10) and (2) the soft wheat Penawawa with a weak gluten (HMWGs 2* / 7+9 / 5+10). In both genetic backgrounds texture was modified by the introgression of the contrasting allelic variant for PIN gens using marker assisted selection: soft texture alleles Pina-D1a/Pinb-D1a from Penawawa were introduced into Buck Poncho and hard texture alleles Pina-D1a/Pinb-D1b from Buck Poncho were introduced into Penawawa. Quality evaluation was carried out using six technological test (nine parameters) according to ICC, AACC and IRAM norms. The analysis included: test weight (TW), grain protein (GP), mixogram development time (MDT), wet gluten content (GC), alveogram parameters (AW) dough strength, solvent retention capacity profile (SRC) test (water -SRCw), latic acid (SRClac, related to gluten quality), sodium carbonate (SRCcarb, related to damaged starch) and sucrose (SRCsuc related to pentosans and gliadins). ANOVA was performed for each variables using as variation source genetic background (GB), grain texture (TEX) and their interaction (GBxTEX). In general the genetic background showed more influence in parameters studied than texture, where Buck Poncho background showed higher effects than Penawawa in all the variables analyzed. Only GC, GP and SRCsuc had no significant differences for the GBxTEX interaction (p = 0.956, p = 0.7091 and p = 0.4885 respectively). It was observed that grain texture only had significant effect on SRCw, SRCsuc and SRClac (p