African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12474

Article in Press

USE OF MARKER ASSISTED SELECTION (MAS) FOR THE CHARACERIZATION AND INTROGRESSION OF RUST RESISTANCE GENES USING AN F2 ROBIN/KWALE POPULATION

BERNICE NGINA WAWERU, PETER NJOROGE NJAU, GODWIN KAMAU MACHARIA, OLIVER KIPLAGAT

  •  Received: 12 April 2017
  •  Accepted: 16 March 2018
Breeding for durably resistant varieties is amongst the best strategies to exterminate the threat posed by stem rust race Ug99 of wheat. This race has continued to spread and ascertain itself as a danger to global wheat production and consequently food security. The continuous swift development of new DNA marker technologies has proved invaluable in breeding for durable rust resistance to stem rust race Ug99 and its lineage of races. This study aimed to characterize resistance to stem rust race Ug99 in a biparental mapping population of a cross between Robin and Kwale. Five seeds of each parental genotype (Kwale and Robin) were sowed nucleic acids isolated from their leaves. They were screened with a panel of 10 SSR markers determine their purity. Results revealed a mixture of genotypes in both parental genotypes, as the screened samples showed different banding patterns to the markers used. An estimated 960 F2 seeds were sowed, and 500 plants were tagged and evaluated for stem rust resistance to race Ug99. A panel of 315 plants were randomly selected from the 500 F2 plants and advanced to F3 generation and screened for stem rust resistance as well. Frequency distribution tables revealed that segregation leaned more towards resistance. Chi square analysis revealed a 13:3 ratio of one dominant and one recessive gene conferring resistance to stem rust. A select number of simple sequence repeat markers were used to characterize the parents and consequently a number of selected homozygous resistant, segregating and homozygous susceptible plants based on their disease scores for resistance genes to stem rust. Molecular characterization revealed several genes present, including SrTmp, Sr2, Lr34 and Sr31. Results of this study underscore the importance of maintaining varietal purity, and proved to encourage use of molecular profile as one the characteristics to be evaluated as part of the distinct uniformity and stability tests prior to variety release.

Keywords: Stem rust, Wheat, Resistance, Polymorphism