Distribution Of Vernalization, Photoperiod, Dwarfing, Kernel Weight And Slow Rust Related Genes Among Cultivars From Major Wheat Regions

Using the molecular markers for vernalization genes Vrn-A1, Vrn-B1, Vrn-D1 and l'rn-B3 and photoperiod gene Ppd-D1, dwarfing genes (Rht-B1b and Rht-D1b) and kernel weight related genes (TaCwi-A1a and Hap-6A-A) and Yr18. the distribution of these genes were detected among 755 cultivars from 23 wheat-growing countries. These cultivars were grown in Anyang, Henan province to observe the days to heading and physiological maturity, plant hight and kernel weight as well as disease resistance. The main conclusions are as follows:(1) Frequencies of Vrn-A1. Vrn-B1. Vrn-D1. vrn-A1+vrn-B1+vrn-D1 and Ppd-D1a in 755 cultivar were 13.0%,21.1%,15.6%,64.6% and 55.6%, respectively. Dominant vernalization alleles Vrn-A1. Vrn-B1 and Vrn-D1 were mainly observed in Chinese spring wheat and Middle and upper Yangtze Valley winter wheat regions, India. Japan. Canada, Mexico. Chile, Argentina and Australia with spring type, while cultivars carried all recessive alleles at the four vernalization loci or the gene recombination vrn-A1, vrn-D1 and Vrn-B1 were found in winter wheat regions of northern China, middle and southern US, Germany. France, Norway, Ukraine. Russia. Turkey, Iran, Hungary, Bulgaria, Romania and Serbia, where the wheat growth habit was winter type.(2) Photoperiod sensitive allele Ppd-D1b was observed in regions with higher latitude or later maturity such as regions of US. Germany, Norway. Hungary. North eastern China. Canada, Chile and Argentina:while photoperiod insensitive allele Ppd-D1a was observed in the other wheat-growing regions. Most of cultivars with photoperiod insensitive allele Ppd-Dla could complete physiological maturity in Anyang, whereas those cultivars from Germany. Norway. Hungary, North western America. North eastern China. Chile and Argentina could not mature well.(3) The frequencies of Rht-B1b and Rht-D1b in 755 Cultivar which were 41.7% and 28.9% in total, respectively, varying much in different wheat-growing countries. Generally speaking, cultivars from the same country usually carry only Rht-B1b or Rht-D1b. the higher frequencies of cultivars with both Rht-B1b and Rht-D1b were detected only in Italy and Australia, while the frequencies of dwarfing genes in the areas with high latitudes such as Canada. Russia and China's northeast spring wheat zone were lower due to less requirement.(4) TaCwi-A1a allele was widely distributed in 23 countries with total frequency of 78%. cultivars from countries excepting Japan (50%), Germany (45.3%) and Chile (48.8%) were detected with higher frequency of TaCwi-A1a allele.29% cultivars carrying Hap-6A-A allele at TaWM2-6A loci, mainly distributing in spring and weak winter wheat, while Hap-6A-G allele widely distributing in winter and strong winter cultivars.(5) 21.7% cultivars carry Yr18. America (18.8%), Ukraine (28.6%), Russia (26.1%), Iran (20.0%). Turkey (34.8%), Hungary (50.0%), Bulgaria (38.9%). Roumania (87.0%). Japan (80.0%), Canada (34.6%) and Australia (44.6%) were detected with higher frequency.(6) TaCwi-A1 molecule markers CWI21 and CWI22 can well detect TaCwi-A1a and TaCwi-A1b alleles respectively, while the CAPS marker of TaWM2-6A can also be used for Kernel weight selecting due to its ability of discriminating Hap-6A-A and Hap-6A-G with great veracity and repeatability. The information is very crucial for use of exotic germplasm in Chinese wheat breeding program.