Assessment of purity of rice hybrids using microsatellite and STS markers

Abstract

The estimation of hybrid rice seed purity is done conventionally by the grow out test (GOT), which is based on the assessment of morphological and floral characteristics in plants grown to maturity. For seed companies, large amounts of capital are locked up in the form of hybrid seed stock while awaiting the results of the GOT. With the objective of replacing the GOT with DNA based assays, cytoplasmic male sterile (CMS), restorer, and hybrid lines have been screened by means of microsatellite and sequence tagged site (STS) polymorphisms. A simple procedure for detecting heterozygosity and purity has been standardized and uses 6‐d‐old rice ( Oryza sativa L.) seedlings, which could be used for detection of off‐types in hybrid seed lots. The extent of heterozygosity within parental lines of rice hybrids was assessed and the results suggest that a single, appropriately chosen microsatellite marker should be sufficient for assessing hybrid seed purity.