Mean and range of grain iron, zinc, protein and thousand kernel weight in RIL population grown in rabi 2012–13 and 2013–14 at ICAR-IARI, GBPUA&T, and Pusa Bihar.

<p>Mean and range of grain iron, zinc, protein and thousand kernel weight in RIL population grown in rabi 2012–13 and 2013–14 at ICAR-IARI, GBPUA&T, and Pusa Bihar.</p

Frequency distributions of grain iron and zinc concentration measured during 2012–13 and 2013–14 in the parents and their RIL population.

<p>Frequency distributions of grain iron and zinc concentration measured during 2012–13 and 2013–14 in the parents and their RIL population.</p

Molecular mapping of the grain iron and zinc concentration, protein content and thousand kernel weight in wheat (<i>Triticum aestivum</i> L.)

<div><p>Genomic regions responsible for accumulation of grain iron concentration (Fe), grain zinc concentration (Zn), grain protein content (PC) and thousand kernel weight (TKW) were investigated in 286 recombinant inbred lines (RILs) derived from a cross between an old Indian wheat variety WH542 and a synthetic derivative (<i>Triticum dicoccon</i> PI94624/<i>Aegilops squarrosa</i> [409]//BCN). RILs were grown in six environments and evaluated for Fe, Zn, PC, and TKW. The population showed the continuous distribution for all the four traits, that for pooled Fe and PC was near normal, whereas, for pooled Zn, RILs exhibited positively skewed distribution. A genetic map spanning 2155.3cM was constructed using microsatellite markers covering the 21 chromosomes and used for QTL analysis. 16 quantitative trait loci (QTL) were identified in this study. Four QTLs (<i>QGFe</i>.<i>iari-2A</i>, <i>QGFe</i>.<i>iari-5A</i>, <i>QGFe</i>.<i>iari-7A</i> and <i>QGFe</i>.<i>iari-7B</i>) for Fe, five QTLs (<i>QGZn</i>.<i>iari-2A</i>, <i>QGZn</i>.<i>iari-4A</i>, <i>QGZn</i>.<i>iari-5A</i>, <i>QGZn</i>.<i>iari-7A</i> and <i>QGZn</i>.<i>iari-7B</i>) for Zn, two QTLs (<i>QGpc</i>.<i>iari-2A</i> and <i>QGpc</i>.<i>iari-3A</i>) for PC, and five QTLs (<i>QTkw</i>.<i>iari-1A</i>, <i>QTkw</i>.<i>iari-2A</i>, <i>QTkw</i>.<i>iari-2B</i>, <i>QTkw</i>.<i>iari-5B</i> and <i>QTkw</i>.<i>iari-7A</i>) for TKW were identified. The QTLs together explained 20.0%, 32.0%, 24.1% and 32.3% phenotypic variation, respectively, for Fe, Zn, PC and TKW. <i>QGpc</i>.<i>iari-2A</i> was consistently expressed in all the six environments, whereas, <i>QGFe</i>.<i>iari-7B</i> and <i>QGZn</i>.<i>iari-2A</i> were identified in two environments each apart from pooled mean. <i>QTkw</i>.<i>iari-2A</i> and <i>QTkw</i>.<i>iari-7A</i>, respectively, were identified in four and three environments apart from pooled mean. A common region in the interval of <i>Xgwm359-Xwmc407</i> on chromosome 2A was associated with Fe, Zn, and PC. One more QTL for TKW was identified on chromosome 2A but in a different chromosomal region (<i>Xgwm382-Xgwm359</i>). Two more regions on 5A (<i>Xgwm126-Xgwm595</i>) and 7A (<i>Xbarc49-Xwmc525</i>) were found to be associated with both Fe and Zn. A QTL for TKW was identified (<i>Xwmc525-Xbarc222</i>) in a different chromosomal region on the same chromosome (7A). This reflects at least a partly common genetic basis for the four traits. It is concluded that fine mapping of the regions of the three chromosomes of A genome involved in determining the accumulation of Fe, Zn, PC, and TKW in this mapping population may be rewarding.</p></div

Estimates of phenotypic correlation coefficients for grain iron, zinc, protein and thousand kernel weight in RILs of WH542 × Synthetic derivative in rabi 2012–2013 and 2013–14 grown at ICAR-IARI, GBPUA&T, and Pusa Bihar.

<p>Estimates of phenotypic correlation coefficients for grain iron, zinc, protein and thousand kernel weight in RILs of WH542 × Synthetic derivative in rabi 2012–2013 and 2013–14 grown at ICAR-IARI, GBPUA&T, and Pusa Bihar.</p

Frequency distributions of grain protein content measured during 2012–13 and 2013–14 in the parents and their RIL population.

<p>Frequency distributions of grain protein content measured during 2012–13 and 2013–14 in the parents and their RIL population.</p

QTLs identified for grain iron, zinc, protein and thousand kernel weight in RILs of WH 542 × Synthetic derivative in rabi 2012–13 and 2013–14 at ICAR-IARI, GBPUA&T and Pusa Bihar.

<p>QTLs identified for grain iron, zinc, protein and thousand kernel weight in RILs of WH 542 × Synthetic derivative in rabi 2012–13 and 2013–14 at ICAR-IARI, GBPUA&T and Pusa Bihar.</p

Elucidating the effects on polyphenol oxidase activity and allelic variation of polyphenol oxidase genes on dough and whole wheat-derived product color parameters

Polyphenol oxidase (PPO) activity is a primary cause of the development of unattractive dark brown discoloration of wheat-based end products. The present study aims to evaluate a set of 41 diverse wheat genotypes grown at three different locations in India for grain phenol color reaction, PPO activity and molecular marker-based characterization of alleles of PPO genes. Relationships among these parameters were analyzed along with the effects of grain PPO activity on dough and chapati color at different time intervals. The mean PPO activity ranged from 7.42 to 27.57 min−1 g−1 10−3 among the genotypes and it showed a significant negative correlation with color brightness (L*) of dough rested for 0 min (r = -0.406), 15 min (r = -0.406), 2 h (r = -0.502) and 4 h (r = -0.551) and whole wheat flour-derived chapati rested for 2 h (r = -0.267) and 4 h (r = -0.424). The overall quality color score was negatively correlated with PPO activity (r = -0.863) and showed a positive correlation with both dough and chapati visual color measured at different time intervals. PPO activity in the genotypes carrying different alleles was found to be Ppo-A1a>Ppo-A1b; Ppo-B2d>Ppo-B2a; and Ppo-D1b>Ppo-D1a. The allelic constitution Ppo-A1bPpo-B2aPpo-D1a and Ppo-A1bPpo-B2dPpo-D1 was found to produce the lowest PPO activity, and thus these alleles are recommended to be used in marker assisted breeding for low PPO activity genotypes to minimize the discoloration of wheat-based end-products.</p