การปรับปรุงข้าวโพดสายพันธุ์แท้ให้ต้านทานโรคราน้ำค้างโดยวิธี Marker-assisted Selection

Abstract

Downy mildew (DM), Peronosclerospora sorghi (Weston and Uppal) C.G. Shaw, is one of the most destructive diseases of maize (Zea mays L.) in Thailand. Understanding the genetic basis of downy mildew resistance could increase the efficiency of breeding for disease resistant germplasm. The objectives of this study were to use the SSR primers associated with QTLs which produced major effects, umc1072 found in chromosome bin 5.07, and bnlg1867 found in chromosome bin 6.01 used to transfer resistance alleles to susceptible lines by marker-assisted selection. A backcross method was carried out in this research. Agron18 and Nei452006 were susceptible lines used as recurrent parent, Nei9008 was resistant line used as donor parent. The results indicated that average percent infection of downy mildew in BC2F1-S1 of population Agron18 x Nei9008 (69 percent) was higher than that of population Nei452006 x Nei9008 (43 percent). Most BC2F1-S1 resistant lines in both populations contained band of Nei9008 at primer umc1072 or bnlg1867 or both primers. It seems that marker assisted selection incorporation with conventional selection can help to improve the efficiency of line improvement for downy mildew resistance.