Inheritance Research For Resistance To Stripe Rust In M852-1and Several Other Wheat Cultivars (Lines)

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the mostimportant diseases of wheat worldwide, especially in China, which is the largest andrelatively independent disease epidemic area. In China, wheat stripe rust mainly occurs innorthwestern, southwestern and huanghuai wheat regions. Epidemic of this disease couldcause about twenty to thirty percent loss on wheat production, even reached to fifty percentif epidemic severe. During1999to2009,4million hectares of wheat suffered from stripe rustevery year averagely in China. It is known that growing resistant cultivars is the mosteconomical, effective and environmental approach to control this disease, according tooverseas and domestic researches and production practice. Due to the simplification ofdisease-resistant wheat cultivars and frequent variation of pathogenic bacteria, less and lesswheat cultivars could resist this disease. Since the1950s, Chinese wheat cultivars have beenreplaced for seven times in main disease epidemic regions. The breeding and utilization ofresistant wheat cultivars bases on excavation of wheat stripe rust resistance gene. So, it isurgent to search for new stripe rust resistance gene for pyramiding genes to achieve high-leveland durable disease-resistance for sustainable control of stripe rust.Elymus mollis is a precious resource for excavating wheat stripe rust resistance genes,with many advantageous traits, such as drought-resistance, salt-tolerance, large panicle, multiinflorescence and resistance to various wheat diseases. Gansu region is not only the birthplaceof Chinese wheat stripe rust fungus, but also severe epidemic area of wheat stripe rust.Lantian18, Tianxuan45and Tianxuan46have been widely grown in Gansu region for manyyears, and resistant to many diseases of wheat. The objective of this study were to identify thegenes for stripe rust resistance in these wheat cultivars (lines) using genetic and molecularmakers. The results are as follows:1、Using seven Pst races of China including CYR29、CYR31、CYR32、CYR33、Su11-4、Su11-7and Su11-11to valuate the fifteen wheat-Elymus mollis translocation lines at theseeding. Five translocation lines presented0to1~+, including M852-1、M8657-2、M8724-1、M8725-2and M8926-2. Six translocation lines presented2to2~+, including M8003-14-4、 M8003-6、M8003-5、M851-2、M857-1and M8664-5. Four translocation lines presented3-~4,including M8926、M8664-3、M8007-1and M851-1.2、The crosses between six translocation lines and Mingxian169were separately testedwith Pst races CYR32and CYR33to identify the genetic of stripe rust resistance genes. Theresistance of M852-1to CYR33was controlled by a single recessive gene. The resistance ofM851-1to CYR32was controlled by a single recessive gene. For M8724-1, two independentrecessive genes conferred resistance to CYR32and one independent recessive gene conferredresistance to CYR33. The resistance of M8725-2to CYR32was controlled by twocomplementary dominant genes and resistance to CYR33was controlled by one dominantgene and one recessive gene independently. The resistance of M8657-2to CYR32wascontrolled by one recessive gene and resistance to CYR33was controlled two independentdominate genes. The resistance of M8926-2to CYR32was controlled by one recessive geneand resistance to CYR33was controlled by one dominant gene and one recessive genecomplementary.3、The M852-1was highly resistant to seven Pst races of China(CYR29、CYR31、CYR32、CYR33、Su11-4、Su11-7and V26), including the most widely virulent andpredominant pathotypes CYR32and CYR33. F1, F2, F3and BC1generations derived fromcross M852-1/Mingxian169were tested with Pst race CYR33. The genetic analysis resultsindicated that the resistance of M852-1to CYR33was controlled by a single recessive gene,tentatively designated as YrElm. The resistance gene was mapped using an F2population fromM852-1/Mingxian169and bulked segregant analysis (BSA). YrElm was linked with fivesimple sequence repeat (SSR) markers, Xcfd35, Xgwm161, Xwmc630, Xgwm533and Xcfd34,which located on wheat chromosome3DS. The genetic distances of closest flanking markers,closest flanking markers, Xcfd35and Xgwm161, were6.5cM and4.2cM, respectively.Pedigree analysisi, chromosomal location and molecular test suggested that YrElm may be anovel resisitance gene to wheat stripe rust, derived from Elymus mollis. Two closest flankingSSR markers, Xcfd35and Xgwm161, were used to test68wheat cultivars from Gansu andHuanghuai wheat region. The results showed that14.7%cultivars had the same polymorphicbands as M852-1. However, resistance identification and pedigree analysis suggested thatthese ten cultivars might not carry the stripe rust resistance gene YrElm. The polymorphicSSR markers identified in this research can be useful in wheat molecular marker selectbreeding and fine mapping.4、Lantian18was resistant to all tested Pst races(CYR31、CYR32、CYR33、Su11-4、Su11-7and Su11-11). Tianxuan45and Tianxuan46were just only susceptible to CYR32.The resistance of Lantian18to CYR32was controlled by two complementary dominate genes and resistance to CYR33was controlled by one dominant gene. The resistance ofTianxuan45to CYR33was controlled by one recessive gene, so was Tianxuan46. This workwill be useful to the proper distribution of disease-resistant wheat cultivars and the mappingof these disease resistance genes.