การพัฒนาสายพันธุ์อินเบรดข้าวโพดที่มีทริปโตแฟนสูงเนื่องจากยีน opaque-2

Abstract

Quality protein maize (QPM) contains the opaque-2 gene for twice tryptophan content along with modifying genes for kernel vitreousness. The QPM hybrid needs the inbred lines containing with opaque-2 gene. Therefore, the objectives of this study were to improve the corn inbred lines with high tryptophan by the opaque-2 gene that detected by molecular marker, and to estimate combing ability of these inbred lines for the yield. Eight lines of BC1S5 containing with opaque-2 gene detected by phi057 were used in the experiment. Tryptophan content in the endosperm of 8 selected lines and 28 of their diallel hybrids were analyzed using glyoxylic method. The yield trial experiment was conducted in randomized complete block design with 4 replications. The plot size was 4 rows of 5 meters long with row spacing 25*75 cm. The results showed that tryptophan content in endosperm of inbred lines was higher and its average was 0.86 percent while variety without opaque-2 gene (SW4452) was about 0.56 percent. On the other hand, the average tryptophan content in endosperm of their hybrids was 0.98% and higher than check variety. The best yield of hybrid was 1,229 kg/rai. It was not different from the check, SW4452 (1,304 kg/rai). P5 and P8 lines were a good general combining ability and suitable for further breeding program.