Marker‐Assisted Backcrossing to Develop an Elite Cytoplasmic Male Sterility Line in Rice

Abstract

Cytoplasmic male sterility (CMS) is a cornerstone of hybrid production in many crops. In three-line hybrid systems, use of CMS, maintainer, and fertility restorer lines is necessary for production of hybrid seeds. Limited resources of CMS and low variation of CMS lines cause genetic vulnerability to pathogens. Therefore, diversifying the CMS sources is indispensible for a sustainable production system of hybrid seed. In this study, we attempted for the first time to transfer CMS into maintainer line Yosen B in restricted generations using the marker-assisted backcrossing (MABC) method. The resultant F 1 hybrid of IR68897 A/Yosen B cross was backcrossed to Yosen B, and CMS plants in each backcross generation (from BC 1 F 1 to BC 3 F 1 ) were selected based on phenotyping test and MABC. Molecular assessment of backcross progenies was conducted using a mitochondrial CMS-specific marker and 34 polymorphic nuclear simple-sequence repeat (SSR) markers in early generations (from BC 1 F 1 to BC 2 F 1 ) and was continued using 9 additional SSRs and 82 inter-simple sequence repeat (ISSR) markers in BC 3 F 1 . A MABC strategy could successfully recover the recurrent parent genome (RPG) in BC 3 F 1 generation, and decreased heterozygosity of final CMS plants. Restorability test with known wild-abortive restorer lines (viz. IR36 and IR24) showed that combination of Yosen A  IR24 could produce highly fertile F 1 hybrid. Evaluation of some important agronomic traits of the final CMS line (BC 4 F 1 ) at field condition showed that it was comparable to the original maintainer fertile counterpart. Phenotypic and marker-assisted selections could considerably decrease the time needed for full recovery of RPG so that final CMS line could show a high similarity to original fertile counterpart.

SSR Polymorphism Survey between CRMS31A and Aruna (MO8) for Marker Assisted Backcross Breeding in Rice

“…Similar to the findings of the present study, Ahmadikhah et al, (2015) had identified 43polymorphic SSR markers by using 100 SSR markers with 30 per cent polymorphism in IR68897A, maternal CMS donor and Yosen B line, which is a potential maintainer line. Whereas Raghvendra and Hittalmani (2018) used 96 polymorphic SSR marker to develop a potential male sterile line for the production of promising hybrids suitable for aerobic conditions with 44% parental polymorphism.…”

Selection Effects in Rice as Assessed by Genetic Analysis in Segregating Populations

“…Evaluation of important traits with direct or indirect effect on grain yield and sustainability of rice growers is indispensable for successful breeding of rice. Estimation of genetic parameters helps our understanding about gene action, identification of components of genetic variances and, finally facilitates the selection of a desirable breeding method (Ahmadikhah et al, 2007, Immanuel et al, 2013Ahmadikhah et al, 2015). The knowledge of genetic variability present in a given crop species for the character under improvement is of paramount importance for the success of any plant breeding program.…”

Use of F2 Bulks in Training Sets for Genomic Prediction of Combining Ability and Hybrid Performance

“…In a CMS system, several cycles of backcrossing are required to develop sterile “A-line” versions of the female inbred lines. In early backcrossing generations, the A-lines still contain significant amounts of donor genome and do not accurately reflect the B-line genotype (Ahmadikhah et al 2015). Neither is necessarily a major concern for production of commercial seed, where CHA applications can be optimized for each commercial hybrid and there is enough time for as many cycles of backcrossing as necessary to remove nearly all residual donor genome.…”