Phenotypic Analysis Of Double Haploid Population In Male Sterile Line337S Of Wheat(Triticum Aestivum L.) And The Relationship Between Heterosis And Genetic Distance

As one of the three main food crops, wheat production plays a vital role in food security issues. Since Sasakuma and Ohtsuka reported the first photo-sensitive male sterility wheat line in1979, many photo-thermo-sensitive male sterility (PTGMS) wheat lines have been discovered.337S is by far the only PTGMS wheat line sensitive to both high temperature for long days and low temperature for short days. Male sterility of337s does not heavily depend on day length, and cytoplasm does not play any negative effect on the sterility.d This line has been widely used for producing hybrids, and shows good overall agronomic characteristics.. Traditional wheat breeding generally requires six or more generations of selfing in order to achieve a relatively homozygous level. Doubling haploid can significancantly shorten breeding periods, and improve the selection efficiency, and genetic research.Agronomic traits and seed setting rate of337s double haploid population were investigated, and the heterosis and genetic distance was measured. Results showed that85%spikelets set seed with variation coefficient of9.41%, indicating that the line was fertility The average genetic distance of337s from the other16parents was0.439. The highest genetic distance was between337s and Zhengmai9023(0.601) largest one, lowest one (0.277) was between337s and Mianyang26.337s×Bainong64was a strong heterosis combination; and the genetic distance between them was0.456, indicating that strong heterosis combination might occur around median of genetic distance. The GD and F1phenotypic value of337s and other parents were positively correlated with SCA performance, but negatively correlated with HM. These results suggested that greater distance genetic between parental combination did not necessarily produce stronger heterosis effect, which also indicated complexity of heterosis.