Marker-assisted pseudo-backcross breeding for improvement of amylose content and aroma in Myanmar rice cultivar Sinthukha

Abstract

Breeding for consumers preferring grain qualities has become a chief goal for rice breeding programs in the world. Amylose content (AC) and aroma are important qualities for consumers' preference and market price. To introgress the alleles of waxy (Wx b) and fragrance (badh2) genes into Sinthukha, a widely adaptable high-yield rice variety in Myanmar which has intermediate AC and non-aroma, RNP20-145-1-9 line was used as a donor parent, and pseudo-backcross breeding was designed to shorten the backcross program. In this approach, only one backcross (BC 1 F 1) and one self-pollinated (BC 1 F 2) population was generated to select for the plants with donor alleles of waxy and fragrance genes in foreground selection, and the selected plants were screened for the highest percentage of recurrent genome content (%RGC) in background selection by amplified fragment length polymorphism (AFLP) analysis. The progenies with the highest %RGC, 84% and 92% were selected in BC 1 F 1 and BC 1 F 2 populations, respectively, and these selected plants possessed heterozygous alleles in fragrance and waxy genes. The agronomic and yield performance, grain size and shape of selected BC 1 F 2 plants were most similar to those of Sinthukha. Nevertheless, amylose content of the selected plants was as low as that of RNP20-145-1-9 rice line. In this study, marker-assisted pseudo-backcross approach was useful in the introgression of low amylose and aroma genes from RNP20-145-1-9 line into Sinthukha, and it could accelerate backcross breeding program through the combination of marker-assisted foreground and background selections. AFLP analysis could save not only time consumption but also the cost of analysis and workload in background selection.

Evaluation of physicochemical characteristics and genetic diversity of widely consumed rice varieties in Kyaukse area, Myanmar

“…Group II consisted of three rice varieties: AYM, STK and MNTK, which exhibited intermediate to high AC, and high-intermediate to high GT. A Similarity coefficient of about 89% showed the closest genetic relationship between MNTK and STK since STK was obtained by the crossing of MNTK and IR BB 21(47…”

Improving yield components and overall yield in M2?M4 phenotypic mutants, induced by EMS, of upland red rice (Oryza sativa L.) cv. Dawk Kha 50

“…In future research, phenotypic variation could be described using genetic analyses, such as genetic linkage maps, whole-genome sequencing, and RNA sequencing, giving a complete image of gene expression differences and single nucleotide polymorphisms contrasted to wild type, based on the source of rice genome. Furthermore, the high rice grain quality genes can be introgressed to rice cultivars having the low grain qualities using a marker-assisted pseudobackcross method [27].…”

Diversity analysis of the Waxy gene in Oryza sativa L. "Guizhou HE"

“…A frameshift due to a 23bp duplication in exon 2 is common [9][10][11][12]. The improvement of amylose content by manipulating the Waxy gene is of prime concern in increasing the quality of rice [13].…”