Identification of bacterial blight resistance genes Xa4 in Pakistani rice germplasm using PCR

Bacterial blight (BB) caused by Xanthomonas oryzae pv oryzae (Xoo) is a major biotic constraint in the irrigated rice belts. Genetic resistance is the most effective and economical control for bacterial blight.Molecular survey was conducted to identify the rice germplasm/lines for the presence of Xa4, a bacterial blight resistance gene. PCR with primers specific for Xa4 resistances gene was used in the study. During this polymorphic survey, out of 100 rice germplasm lines obtained from NARC (IABGR), 49 lines were observed with Xa4 gene. While 51 germplasm showed the absence of Xa4 gene. Of the nineteen basmati breeding lines, obtained from Rice Research Station Kala Shah Kaku (KSK RRI), 7 lines (KSK1, KSK4, KSK6, KSK7, KSK8, KSK12 and KSK16) showed the presence of Xa4 gene. The Pakistani released Basmati varieties were also surveyed. Of the eight Pakistani basmati varieties used, Basmati 198, Basmati 385, Basmati 2000 and Shaheen Basmati have the Xa4 gene. The identification of Xa4 gene in Pakistani rice germplasm will help in accelerating the elite breeding program in future, including pyramiding of different disease resistant genes in basmati varieties