Assessment of genetic purity in hybrid rice seeds using grow-out test and DNA markers

Abstract:

In West Africa’s rapidly expanding hybrid rice sector, seed purity is the gatekeeper between a productive crop and a field of off-types that disappoint farmers and erode trust in the seed system. This research compared two methods for assessing genetic purity — the conventional grow-out test (GOT) and SSR DNA markers — across five commercial hybrid rice entries (KRH-4, DRRH-3, PA 6201, PHB 71, 27P31) produced at Calabar, Nigeria, during 2022–23. GOT purity ranged from 93.1% to 97.6%, while DNA-marker purity ranged from 94.6% to 98.2%. The two methods showed strong positive correlation (r = 0.94, p = 0.017), but DNA markers consistently detected 1.0–1.5% more off-types than GOT, likely because molecular assays identify heterozygous loci invisible to visual phenotyping. Three SSR markers (RM164, RM206, RM263) correctly distinguished all five hybrids from their parental lines in a single multiplex PCR reaction. These results support integrating DNA-marker testing alongside GOT in Nigerian seed certification to improve detection accuracy and reduce the time from harvest to market release.