To determine the genetic differences between high molecular weigh glutenin subunits （HMW-GS） null and 1. HMW-GS 1 was introduced into Longfumai 3 （N, 7＋8, 5＋10） by 5 consecutive backcrosses with biochemical marker assisted selection. The near isogenic lines （NILs） of HMW-GS null and 1 were obtained and planted in the experimental field of Crop Breeding Institute of Heilongjiang Academy of Agricultural Science in 2004 and 2005. The field experiments were designed using the method of two-line contrast arrangement with four replicates. The result of two years experiment showed that the statistic differences of quality parameters between Longfumai 3 with subunit 1 and with null were not significant in flour protein content, dry gluten content, and water absorption. However the gluten index,＇ Zeleny sedimentation, the ratio of sedimentation/dry gluten, the development time, stability, and the breakdown time in the NIL with 1 subunit were increased by 5.8% （P〈0.01）, 9.3% （P〈0.01）, 8.6% （P=0.01）, 127.3% （P〈0.01）, 79.2% （P〈0.01）, and 53.6% （P〈0.01）, and the ratio of wet gluten/dry gluten and the degree of softening were decreased by 1.7% （P = 0.05） and 16.5% （P = 0.13）, respectively. The impact of the HMW-GS 1 on the gluten strength was highly positive in NILs containing HMW-GS 5 ＋ 10, suggesting that HMW-GS 1 can be an indispensable subunit for breeding strong gluten wheat.
To investigate the effect of high molecular weight glutenin subunits (HMW-GS) 5+10 inhigh quality spring wheat, four near-isogenic lines (NILs) developed by 6 consecutivebackcrosses sharing the same genetic background and differing only at the Glu-D1 locusin each pair were employed in this study. The results showed that gluten indexes were allincreased by 3.1-27.7% (P<0.01) after the 5+10 subunits introduced into the fourcultivars. Their stability time was increased by 128, 104, 233 and 36%, where the maximumresistance raised by 130, 56.04, 95.10 and 16.33% in Kefeng6, Longmai20, Longfumai10and Xiaobingmai33, respectively.
