Marker Assisted Foreground Selection of Back Cross Genotypes for Leaf Rust Resistance in Wheat (Triticum aestivum L.)

Abstract

The investigation was undertaken to identify desirable wheat genotypes at BC1 generation carrying leaf rust resistance alleles using molecular markers. The F1 was generated from cross NI5643 (lacking Lr34) × NIAW34 (carrying Lr34). The F1 was confirmed by using simple sequence repeats (SSR) marker gwm389. This F1 was used for crossing with recurrent parent NI5643 (lacking Lr34) and BC1 plants were produced. Twenty five BC1 plants were screened for the presence of Lr34, by using SSR primers. For this purpose markers from chromosome 7D i.e. cssfr1, cssfr2, KUDS, barc352 were used to screen parental genotypes. All these markers did not show polymorphism among parental genotypes. Therefore these were not used for foreground selection. Another marker from chromosome 7D, wms130 was used to screen BC1 plants for the presence of Lr34 (foreground selection). As per the SSR profile generated by primer wms130, the plants 1, 3, 4, 6, 10, 12, 13, 14, 15, 16, 18, 22 and 25 were found positive for Lr34. Another 10 markers i.e. gwm389, wmc313, wmc468, gwm610, wmc707, gwm60, wmc525, barc137, wmc419 and barc62 were used for background selection. The plants with heterozygous amplification pattern were selected for developing BC2 plants. BC1 plants that are heterozygous or positive for Lr34 using all the markers are 1, 3, 4, 6, 10, 12, 13, 14, 15, 16, 18, 20, 22, 23 and 25. Based on foreground selection and background selection, a total of 15 plants were found carrying desirable alleles and were used for developing BC2. Highlights m Present study was thus carried out with the objective to identify desirable wheat genotypes at BC1 generation containing leaf rust resistance alleles using molecular markers.