Abstract
BackgroundRice blast disease is a major restriction in rice production. That is usually managed using chemical pesticides, which are expensive in terms of cost and environment hazards. Use of blast-resistance genes to develop resistant varieties may therefore be a more economical and environmentally friendly method for effective control.ResultsIn this study, we improved the blast resistance of four sterile lines, Y58S, GuangZhan63S (GZ63), C815S and HD9802S, by introgression of 9 cloned broad-spectrum blast resistance genes Pi37, Pit, Pid3, Pigm, Pi36, Pi5, Pi54, Pikm and Pb1. Through molecular marker-assisted selection and backcross breeding, 31 single-gene derived lines and 20 double-gene combination lines were obtained. When infected naturally, single-gene lines with Pigm or Pid3 showed significantly enhanced resistance during whole growth period relative to their recurrent parent. Single-gene lines with Pi37, Pi5, Pit, Pi36, Pi54 or Pikm showed significantly enhanced resistance in some of the four backgrounds. No obviously enhanced resistance was observed in single-gene line with Pb1 for the whole growth period. Compared with recurrent parents, most of the double-gene lines showed improved resistance. Among these double-gene lines, lines with Pi37/Pid3, Pi5/Pi54, Pi54/Pid3 or Pigm/Pi37, exhibited significantly enhanced resistance and observable additive effects.ConclusionsTwo blast resistance genes, Pigm and Pid3, showed significantly enhanced resistance for the whole rice growth period, and six blast resistance genes Pi37, Pi5, Pit, Pi36, Pi54 or Pikm showed significantly enhanced resistance for some of the four backgrounds. Double-gene lines with Pi37/Pid3, Pi5/Pi54, Pi54/Pid3 and Pigm/Pi37 exhibited significantly enhanced resistance and observable additive effects. These lines could be used in rice hybrid and production.
Highlights
Rice (Oryza sativa) is a staple food crop for more than 50% of the world’s population
Rice blast disease is a major restriction on rice production in both tropical and temperate countries, and it is a major obstacle to hybrid rice production in China due to the relatively narrow genetic base of hybrid rice and the increased use of nitrogen fertilizer (Liu et al 2010a)
Pikm for blast resistance was introgressed into C815S and HD9802S, and Pb1 for blast resistance was introgressed into GZ63S, using the marker-assisted backcross breeding method (Fig. 1)
Summary
Rice (Oryza sativa) is a staple food crop for more than 50% of the world’s population. The average blast infected area was more than 3.8 million hectares in 1982–1985, with yield losses of several million tons (Sun et al 1999). In. 1993, a yield loss of 1.1 million tons was recorded in Southern China alone. Conventional methods of controlling blast depended on fungicides, which generate additional costs in rice production and chemical contamination of the environment and food. The development and use of resistant varieties with the major resistance genes is one of the most economical and effective ways to control this disease (Koide et al 2009; Deng et al 2017). Rice blast disease is a major restriction in rice production. Use of blast-resistance genes to develop resistant varieties may be a more economical and environmentally friendly method for effective control
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