Logo Genetic purity testing of two-line hybrid rice seeds by ultrathin-layer isoelectric focusing of proteins

Abstract

To test for inbreds among F1 seeds of two-line hybrid rice (Oryza sativa L.) in the laboratory, ultrathin-layer isoelectric focusing (UTLIEF) of seed proteins was used. One female marker band in the photo-thermo-sensitive genic male sterile rice (cv. Peiai 64S) and one common male marker band in the four restorer lines (cv. G67, Peifu, I9-1 and Minkezhan) were found in the pH range of 5-8. Embryoless half-seeds contained the same male marker proteins as whole seeds and could be used for UTLIEF to test inbreds in the laboratory. The corresponding embryo-containing half-seeds could germinate to form seedlings on vermiculite and seedlings could be transplanted into the field for grow-out tests. The genetic purity determined by UTLIEF of proteins from embryoless half-seeds was confirmed by grow-out tests of the corresponding embryo-containing half-seeds. This work shows that UTLIEF of seed proteins could replace grow-out tests to determine F1 genetic purity of two-line hybrid rice. Using half-seeds, the comparison between laboratory and field tests was more objective and accurate than using whole seeds.