Abstract
Rice is the most significant global food security. Several biotic factors limit rice production, breeding biotic-resistant rice has, therefore, become an increasingly important goal. Two elite rice lines, IR71033-121-15 (IR71033) and IR57514-PMI-5-B-1-2 (IR57514), provide potential genes for biotic stress resistance traits. In this study, genotyping by sequencing (GBS) for single nucleotide polymorphism (SNP)-based linkage map construction was used to detect quantitative trait loci (QTLs) for blast (BL), bacterial blight (BB), whitebacked planthopper (WBPH), and brown planthopper (BPH) resistance. IR71033 was derived from Oryza minuta and carried BL, BB, WBPH, and BPH resistance QTLs. IR57514 is a well-adapted rainfed lowland line that carries BL and BB resistance QTLs. Two sets of recombinant inbred line (RIL) populations derived from crosses of KDML105 × IR71033 and KDML105 × IR57514 were used to dissect the genetic basis of disease and insect pest resistance. The RIL populations were evaluated for BL, BB, WBPH, and BPH resistance from 2016 to 2018 at four rice research centers in Thailand. From these, we identified a large number of SNPs through GBS and constructed high-resolution linkage maps. By combining phenotypic evaluation with the GBS data, a total of 24 QTLs on four chromosomes were detected that confered pest resistance and explained 7.3% - 61.4% of the phenotypic variance. These findings should facilitate identifying novel resistance genes and applying marker-assisted selection for resistance to the four major rice pests investigated here. These strategies will improve the resilience and reliability of rice varieties adapted to the low-yielding environment of rainfed lowland areas worldwide.
Highlights
Among the biotic stressors of rice, blast (BL), bacterial blight (BB), white backed planthopper (WBPH), and brown planthopper (BPH) are the four major pathogens affecting rainfed lowland rice; they are caused by Magnaporthe grisea, Xanthomonas oryzae pv. oryzae, Sogatella furcifera, and Nilaparvata lugens, respectively
65% of the area is dominated by Khao Dawk Mali 105” (KDML105), which is well adapted to the low-yielding environment of rainfed lowland conditions [2]
Our results suggest that IR71033 and IR57514 could potentially provide multiple important genes for biotic stress resistance including against BL, BB, whitebacked planthopper (WBPH), and BPH in multiple environments
Summary
Among the biotic stressors of rice, blast (BL), bacterial blight (BB), white backed planthopper (WBPH), and brown planthopper (BPH) are the four major pathogens affecting rainfed lowland rice; they are caused by Magnaporthe grisea, Xanthomonas oryzae pv. oryzae, Sogatella furcifera, and Nilaparvata lugens, respectively. Oryzae, Sogatella furcifera, and Nilaparvata lugens, respectively. These destructive pests greatly reduce rice yield throughout the rainfed lowlands in Asia and in the northeast (NE) of Thailand [1] [2]. 65% of the area is dominated by KDML105, which is well adapted to the low-yielding environment of rainfed lowland conditions [2]. This strain is highly susceptible to BL, BB, WBPH, and BPH. In 2018, BL and BPH outbreaks destroyed close to 80% of the rice crop in the rainfed lowland areas of the lower part of the NE [4]. The development of resistant varieties is considered to be the most effective and economical means of maintaining yield stability by controlling the major rice pests in the frequent outbreak areas [5] [6]
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