Breeding of Sweet Shinhong pepper by Marker-assisted backcrossing (MABC)

Abstract

Capsinoids is unique compound of pepper, which have similar biological effect to apsaicinoids like anticancer and anti-obesity. However, because the characteristic of capsinoids is non-pungency contrary to capsaicinoids, it has been studied to investigate genetic factor related to biosynthesis of capsinoids and to breed pepper variety producing capsinoids. Two pathway are known to be involved in capsaicinoids synthesis, phenylpropanoid and valine pathway. Capsinoids biosynthesis pathway is common to capsaicinoids, but putative-aminotransferase (pAMT) gene mutation in phenylpropanoid pathway cause capsinoids production instead of capsaicinoids. SNU11-001 which have pAMT gene mutation produce high level of capsinoids and Shinhong is Korean chili pepper. In previous research, pAMT mutation in SNU11-001 have been introgressed to Shinhong to breed novel Shinhong pepper containing high contents of capsinoids by Marker-Assisted Backcrossing (MABC) method. Recessive homozygous pAMT allele was selected by genotyping with KASP marker for foreground selection and 8 to 10 plants which recovered by Shinhong genome highly were selected by Fluidigm high-throughput genotyping analysis. Shinhong C × SNU11-001 (SSHC) BC2F1-40 was selected by MABC with 198 SNP markers and recovery rate was 96.3%. In this study, MABC of SNU11-001 × Shinhong C (SSHC) BC3F1 and SNU11-001 × Shinhong B (SSHB) BC2F1 was proceeded. 202 and 102 markers were used for background selection, respectively. 10 SSHC BC3F1 progenies showed the highest recovery rate, 99.5%. The range of recovery rate in SSHB BC2F1 was 89.6 to 96.7%. SSHC BC2F2 was from self-crossing of SSHC BC2F1-40 and several pamt/pamt plants were selected. We will develop SSHB BC2F2 line which have pAMT mutation allele and high recovery rate of Shinhong B. This SSHB BC2F2 progeny will have cytoplasmic male sterility by being crossed with Shinhong A. Finally we will be able to breed sweet Shinhong F1 hybrid containing high level of capsinoids.