Production of doubled-haploid(DH) selfed-progenies in ‘Banpeiyu’ pummelo [Citrus maxima (Burm.) Merr.] and its genetic analysis with simple sequence repeat markers

Abstract

The genetic analysis of five haploid plants (BX1-BX5) of ‘Banpeiyu’ pummelo (BP), [Citrus maxima (Burm.) Merr.] using 32 simple sequence repeat (SSR) markers carried out for the purpose of confirming their gynogenetic origin and genetic differences. As the results, all the haploid plants possessed only either one of the BP alleles, confirming that they are gynogenetic origin. We also confirmed that BX1 and its doubled haploid (BX1-DH) have exactly the same SSR alleles. Interestingly, all the five haploids had common alleles on the linkage group (LG) 6 in the case of three markers. Then, we performed self-pollination of DH plants and reciprocal crosses between DH and BP, which has strong self-incompatibility. The seeds obtained by these crosses germinated in vitro or ex vitro normally and developed into diploid seedlings, except for one tetraploid seedling. Genetic analysis of these seedlings with 32 SSR markers revealed that segregation ratios of the 32 loci in the 30 BP inbred, 30 BP x DH and 30 DH x BP progenies mostly fitted to the expected ratios. However, significantly distorted segregation ratios were found in one, five and three SSR markers for BP inbred, BP x DH and DH x BP progenies, respectively. All of the 30 DH inbred progenies showed exactly the same SSR alleles as the original DH. This is the first example in which self and back cross progenies of DH in fruit crops were genetically analyzed using SSR markers.