AUTHOR=Priyadarshi Rahul , Arremsetty Hari P. S. , Singh Akhilesh K. , Khandekar Durga , Ulaganathan Kandasamy , Shenoy Vinay , Sinha Pallavi , Singh Vikas K. 

TITLE=Marker-Assisted Improvement of the Elite Maintainer Line of Rice, IR 58025B for Wide Compatibility (S5n) Gene

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.01051

DOI=10.3389/fpls.2018.01051

ISSN=1664-462X

ABSTRACT=<p>The degree of heterosis in different hybrid rice varieties is reported to be at the highest in <italic>indica</italic>/<italic>japonica</italic> cross combination, however, there is a problem of sterility and semi-sterility in such inter sub specific hybrids. To overcome this problem, it is essential to develop parental lines having wide compatibility (<italic>S5</italic><sup><italic>n</italic></sup>) gene. In this study, a functional marker S5-InDel was used for marker-assisted backcrossing (MABB) to introgress <italic>S5</italic><sup><italic>n</italic></sup> gene from Dular into the genetic background of a widely grown recurrent parent IR 58025B, a maintainer line of wild-abortive (WA) cytoplasmic male sterile line, IR 58025A. Further, a closely linked marker <italic>nksbadh2</italic> was used for the identification of plants devoid of aroma in backcross population to develop hybrids with no aroma. The stringent phenotypic selection followed by background selection of BC<sub>3</sub>F<sub>4</sub> identified plants with 94.51–98.90% of the recurrent parent genome recovery of lines carrying <italic>S5</italic><sup><italic>n</italic></sup> gene. Subsequently, at 10 promising BC<sub>3</sub>F<sub>5</sub> lines possessing <italic>S5</italic><sup><italic>n</italic></sup> gene with high yielding and long-slender grain type were validated for their maintainer behavior through test crosses with IR 58025A. Also the improved lines showed significantly improved spikelet fertility performance while crossed with <italic>japonica</italic> and <italic>javanica</italic> testers in comparison to the original recurrent parent. The improved lines developed in the present study, are being converted to CMS lines through marker-assisted backcross breeding to facilitate precise and improved hybrid breeding program in rice.</p>