Fine Mapping Of Amajor Scab Resistance QTL On Chromosome3B Of Wheat

A major QTL for type Ⅱ resistant to Fusarium Head Blight on chromosome3BS was detected in a lot of resistant wheat germplasms. In our laboratory, with the help of molecular markers assisted selection, using Mianyang99-323and PH691as recurrent parent, Qfhs.nau-3BNILs derived from resistant cultivar "Wangshuibai" were developed. In this research, the resistance and agronomic traits of these NILs were investigated to evaluate the effect of this QTL and its influence on agronomic traits. These NILs had average reduction of more than60%for NDS and more than46%for LDR, respectively. With the agronomical traits, NILs were similar to the recurrent parent. Their plant height, spike length, spikelet numbers, flag leaf length, flag leaf width and number of effective tillers had no significant differences compared to the recurrent parent.To definite dominant or recessive heredity of Qfhs.nau-3B, we evaluated the F1and F2population from Wangshuibai Qfhs.nau-3B NIL crossed with its recurrent parent Mianyang99-323. The results showed that F1plants were susceptible to FHB and the resistance segregation of F2was1:3, so Qfhs.nau-3B from Wangshuibai is recessive inheritance.To precisely mapQfhs.nau-3B, we used theF2population and molecular markers that closely linked with this QTL to select recombinants and obtained118homozygotes. At the same time5recombinants withQfhs.nau-3BnoQfhs.nau-6B from Nanda2419×Wangshuibai RIL population were selscted. These recombinants have significant differences in resistance to FHB according to phenotype, and can be classified into resistant group and susceptible group. According to their genotype and resistance appearance, Qfhs.nau-3B was mapped in the interval of Xmag6067-Xmag6661with the physical distance170.5Kb.