A New Rice Cultivar ‘Shinbaek’ Resistant to K3a Race of Bacterial Blight

Abstract

Bacterial blight (BB) disease is one of the most serious rice diseases in Korea. xa5 showing a wider spectrum resistance to Korean BB isolates is one of the most important bacterial blight resistance genes in rice breeding in Korea. A new rice cultivar 'Shinbaek' carrying xa5 gene was developed at the rice breeding team of the Department of Functional Crop, NICS, RDA in 2010. 'Shinbaek' was derived from the cross between 'Iksan469 and 'HR23966-22-1-2' carrying xa5 gene which was originated from indica rice 'IRBB5'. 'Shinbaek' is resistance to a major Korean BB isolate such as K1, K2, K3 and K3a, and it is also resistance tor ice stripe virus disease (RSV). Heading date of 'Shinbaek' is August 11 as mid maturing ecotype. The major agronomic characteristics of 'Shinbaek' is good plant type with short culm length, longer panicle length, higher number of spikelet per panicle as compared to those of 'Nampyeongbyeo', However, the number of tiller and grain filling ratio were lower compared to that of 'Nampyeongbyeo'. The grain appearance, amylose content, and protein content were similar with those of 'Nampyeongbyeo'. However the palatability of cooked rice and milling recovery were still lower than those of 'Nampyeongbyeo'. The milled rice yield of 'Shinbaek' is 5.75 MT per ha, 5.49 MT per ha and 4.68 MT per ha at the ordinary transplanting, double-crop system, and late transplanting of the local adaptability test, respectively. Thus, 'Shinbaek' would be a suitable cultivar to the mid and southern plain area, especially in BB disease prone area and it is a useful source to enhance the BB resistant breeding program.