Complementary gene controlling the black hull phenotype and phenolics and flavonoids content in weedy rice (Oryza sativa f. spontanea) from northeastern Thailand

Abstract

A complementary gene black seed hull 4 (Bh4 and Phr1) is a hull color candidate gene that causes a black pigmentation in the ripened hulls of rice. The relationship between Bh4 and Phr1 in the black hull phenotype was elucidated previously. In this study, 82 ripened weed rice seed samples were collected to analyze the relationships between the phenotype and genotype of the two genes controlling seed hull color and to evaluate the phytochemical compounds in weedy rice grains. The results showed evidence which strongly supported the hypothesis of a complementary gene (Bh4 and Phr1) controlling black seed hull in rice. The total phenolic content of brown weedy rice grains of black seed hull (2.58 mgGAE/ g) and straw seed hull (1.58 mg GAE/ g) with red pericarp was higher than weedy rice with black seed hull white pericarp (0.27 mg GAE/ g) and two traditional red rice varieties (Mun Pu, 1.51 mg GAE/ g), Niew Daeng, 1.24 mg GAE/ g). Total flavonoid content of the brown weedy rice grains revealed a similar trend with total phenolic content. This observation indicated that weedy rice is a rich source of phytochemicals that might have potential benefits for human health.

Keywords

• weedy rice
• seed hull color
• phytochemical compounds