2NVS translocation presence and inheritance of resistance to head blast in wheat

Abstract

The objective of this work was to evaluate the effect of the presence of 2N^VS translocation on the inheritance of wheat resistance to head blast, in F2 segregating lines from two biparental crosses. The IPF 86766 and 'Santa Fe' genotypes were used as female parents (both 2N^VS carriers), and 'BRS 404', as the common male parent (non 2N^VS carrier). Using a mixture of three isolates of Pyricularia oryzae Triticum, wheat spikes and rachises were evaluated for bleaching severity at five (%BS_5dpi) and seven days post-inoculation (%BS_7dpi), as well as for the number of infection points (IPR) and pathogen sporulation (SPO). Chi-square analyses showed that segregation follows a 3:1 Mendelian hypothesis, with a major locus with a dominant allele: %BS_7dpi for IPF 86766 x 'BRS 404' and IPR for 'Santa Fe' x 'BRS 404'. Therefore, this is the first known study to show that the 2N^VS translocation responsible for resistance to head blast is a major locus with a dominant allele. In a controlled environment, 'BRS 404' shows bleaching severity and SPO similar with those occurring on IPF 86766 and 'Santa Fe'.