Quality Difference of Near-Isogenic Lines with HMW Glutenin Subunits 7+8~* and 17+18 in Wheat Cultivars Longmai 20

【Objective】 Determining the genetic differences between high molecular weigh glutenin subunits (HMW-GS) 17+18 and 7+8*.【Method】 HMW-GS 7+8* was introduced into Longmai 20 (1,17+18, 5+10) by 5 consecutive backcrosses with biochemical marker assisted selection from a Canadian extra strong wheat cultivar Glenlea possessing an over expression of the Bx7 subunit. The near isogenic lines (NILs) of HMW-GS 17+18 and 7+8* were obtained and grown in the experimental field of Crop Breeding Institute of Heilongjiang Academy of Agricultural Sciences, Harbin in 2005. The experimental design was a randomized block with six replicates. 【Result】In comparison to NILs with 17+18 subunit, the average of quality parameters of NILs with 7+8* subunit were 5% (P=0.012), 4% (P =0.018), 10% (P=0.013), 13% (P=0.258), 256% (P=0.029) and 86% (P =0.020) higher in flour protein content, dry gluten content, Zeleny sedimentation, development time, stability and breakdown time, respectively, and were 2% (P =0.043) and 35% (P=0.007) lower in the ratios of wet gluten content to dry gluten content (wet gluten/dry gluten ) and degree of softening, respectively. 【Conclusion】The subunits 7+8* have a strong positive effect on dough strength.