Application of a simplified marker-assisted backcross technique for hybrid breeding in rice

Abstract

Hybrid rice has contributed greatly to the self-sufficiency of the food supply in China. However, bacterial blight is a major disease that limits hybrid rice production in China. The study was conducted to develop an efficient breeding technique to improve the bacterial blight resistance in hybrid rice. A marker-assisted backcross breeding technique was adopted to improve HN189, an elite restorer line containing the Pi1 gene. This breeding technique was simplified to foreground selection with only one generation of backcrossing and background selection based on phenotypic selection. A novel bacterial blight resistance gene, Xa23, was introgressed into HN189. Two improved restorer lines, HBH145 (with one generation of backcrossing) and HBH146 (with two generations of backcrossing), were obtained that had a significant bacterial blight resistance advantage over HN189. The corresponding hybrid combination Tianyou H145 (Tianfeng A / HBH145) was certified one year earlier than Qianyou H146 (Qianjiang 1A / HBH146). The use of the marker-assisted backcross breeding technique with one generation of backcrossing and without background selection in rice breeding programs shortened the breeding period of the rice.

Recent advancements in molecular marker-assisted selection and applications in plant breeding programmes

“…Molecular markers encourage determination because molecular or DNA-based markers are non-destructive and encoding of markers for various desirable genes can be tried utilizing a single DNA test without phenotyping. Joining numerous genes of disease resistance or QTLs to provide durability against disease resistance has been the most across-the-board utilization of pyramiding in plant breeding [ 92 , 93 ]. Although it is yet conceivable to utilize traditional breeding, it is troublesome or unthinkable at an early generation because of the need to phenotypically screen each plant for all characteristics being tested.…”

Recent Advances in Rice Varietal Development for Durable Resistance to Biotic and Abiotic Stresses through Marker-Assisted Gene Pyramiding

“…Gene pyramiding implies the derivation of a perfect genotype where favorable alleles are homozygous states at all loci. There are two parts to gene pyramiding; the pedigree step and the fixation step [25]. First, the pedigree step desires to accumulate all of the targeted genes from multiple parents into a single root genotype.…”

Marker-assisted selection and gene pyramiding for resistance to bacterial leaf blight disease of rice (Oryza sativaL.)

“…Molecular markers facilitate selection because molecular or DNA-based marker assays are non-destructive and markers encoding for several target genes can be tested using a single DNA sample without phenotyping. Combining multiple disease resistance genes or QTLs so as to provide durable disease resistance has been the most widespread application of pyramiding in plant breeding [60,116]. Although it is still possible to use conventional breeding, it is very difficult or nearly impossible at the early generations due to the need to phenotypically screen each plant for all traits being tested.…”

“…The development of molecular genetics and associated technology like markerassisted selection has led to the emergence of a new field in plant breeding called gene pyramiding. The gene pyramiding scheme can be distinguished into two parts [116]. The first part is called a pedigree, which aims at cumulating all the target genes in a single genotype called the root genotype.…”

“…Molecular marker genotyping can facilitate the gene pyramiding process by reducing the number of generations that breeders must evaluate to ensure they have the desired gene combination. Gene pyramiding is an important strategy for germplasm improvement [116,117,125,126].…”