Aug 2026· International journal of agricultural sciences and veterinary medicine· Vol 14, pp. 1· 0 citations
Abstract
In the current study, a marker-assisted backcross
breeding (MABB) strategy was employed to transfer
two bacterial blight (BB) resistance genes (Xa21 and
xa13) alongside a dwarfing gene (sd1) into Ranbir
Basmati. The molecular markers, specifically pTA 248,
xa13prom and h, which are associated with Xa21, xa13
and sd1 respectively, were utilized in the MABB
programme. Both foreground and background
selection methods were applied to pyramid the genes of
interest into the variety.
Crosses were conducted to integrate the BB resistance
genes and the dwarfing gene from Punjab Basmati 4
(Xa21, xa13 and sd1) into Ranbir Basmati. The MABB
programme progressed up to the BC3F6 generations. A
total of four semi-dwarf pyramided lines, namely SJBR
145-22, SJBR 145-34, SBJR-129-06 and SBJR-139-14
have been identified for subsequent field screening.
These pyramided lines exhibited excellent cooking
qualities and a pleasant aroma. Further evaluations of
these four lines for morpho-physiological and quality
traits indicated the potential donors for various rice
pre-breeding programmes.
Background: Uma is a high-yielding, popular red-kernelled rice variety of Kerala; however, the occurrence of BB disease often causes severe yield reductions in this cultivar. Host plant resistance based on multiple genes is the most effective measure to impart durable resistance. Hence, efforts were undertaken to introgress the resistance genes, xa 5, xa13 and Xa21, from a BB-resistant variety, ISM, into Uma, using the MABB approach. Methods: Foreground selection was carried out using markers RG 556 and xa5 SR for xa5, RG136 and xa13 promoter for xa13 and pTA248 for Xa21 genes, respectively. The identified R-gene-pyramided plant was subjected to background selection using rice microsatellite markers for recurrent parent genome recovery. The phenotypic evaluation for BB resistance was carried out using the leaf-clipping method following the IRRI standard evaluation system, SES. Result: Molecular analysis of the recurrent parent Uma revealed the endogenous presence of R gene xa 5. The evaluation of BC2F1 lines identified a single plant pyramided with three resistance genes, with xa13 and Xa21 in the heterozygous condition, exhibiting a recurrent parent genome recovery of 70.45% and kernel characteristics similar to those of the Uma. Concurrently, BC1F2 lines generated from the cross were phenotypically screened for BB resistance, also identifying resistance to moderate resistance lines to the BB pathogen. Further advancement of these backcross generations was proposed to isolate gene pyramids homozygous for the resistance genes, with near-complete recurrent parent genome recovery.
Bhartiya Krishi, Anusandhan Patrika, L. Megha et al.· Bhartiya Krishi Anusandhan P...· 0 citations
Sixty advanced breeding lines of rice were evaluated for resistance to bacterial leaf blight (BLB) both phenotypically and genotypically at Regional Agricultural Research Station (RARS), Maruteru, Andhra Pradesh, India during kharif, 2023. Phenotypic screening was performed following the International Rice Research Institute (IRRI), standard evaluation system (SES) scale. Among the sixty entries, seven genotypes, 251-3-3-2, MS-1, NLR-163, NLR-164, NLR-945, CM-469 and BM-587, exhibited a highly resistant (HR) reaction with a score of 1, comparable to the resistant check RP Bio-226. Twenty-two lines expressed BLB severity of 13–25 % (score 5) and were categorised as moderately resistant (MR). Molecular profiling using gene-specific simple sequence repeats (SSR) markers revealed significant variation in resistance genedistribution. The presence of xa5, xa13, Xa21, Xa4 and Xa10 was detected in 9, 4, 23, 44 and 20 lines respectively. Two-gene combinations were identified in 20 genotypes, whereas 11 genotypes possessed three-gene combinations, highlighting the effectiveness of gene stacking for broad-spectrum BLB resistance. Notably, lines 251-3-3-2, MS-1, NLR-164, NLR-945 and BM-587 exhibited congruence between phenotypic resistance (score 1) and the presence of multiple resistance genes, indicating their potential as elite donors for BLB resistance introgression. Yield performance coupled with gene pyramiding further strengthened the value of several genotypes. The genotypes VP-R-157 (Xa4+xa13) recorded 22.3 g/plant, BM-588 (xa5+Xa21) yielded 21.2 g/plant, while CM-467 (Xa4+xa5+Xa10+Xa21) produced 25.1 g/plant. The genotypes CM-470, CM-446 and CM-449 yielded 26.3 g, 21.0 g and 21.5 g/plant respectively, each carrying the Xa4+xa5 gene combination. These genotypes hold substantial promise for direct varietal release or utilisation in hybridisation programs aimed at developing high-yielding, BLB-resistant rice cultivars.
M. Jahnavi, Y. Satish, R. M. Ramabhadra et al.· Plant Science Today· 0 citations
Background: Aromatic rice quality is primarily determined by loss-of-function mutations in the BADH2 gene, which lead to the accumulation of 2-acetyl-1-pyrroline (2AP). This study aimed to introgress the BADH2 aromatic allele from Merah Wangi into the high-yielding variety Inpari 33 and to evaluate the agronomic performance of the resulting BC4F1 population. Methods: A breeding program consisting of four backcross cycles was conducted using Inpari 33 as the recurrent parent and Merah Wangi as the donor parent. Marker Marker-assisted breeding using Bradbury markers was applied to identify plants carrying the BADH2 mutation. Agronomic traits, including heading date, plant height, panicle length, tillering capacity, yield components and grain quality were assessed to characterize phenotypic performance. Result: Twenty heterozygous aromatic plants were identified, confirming successful introgression of the BADH2 mutant allele. The BC4F1 population showed uniform heading date, intermediate plant height and increased panicle length relative to Inpari 33. The productive tillers, filled grains per panicle and grain yield per plant demonstrated improved performance, even though variability persisted in grain filling and 1000-grain weight. These findings indicate that the integration of the BADH2 allele and the overall agronomic response validate the effectiveness of Marker Assisted Breeding combined with repeated backcrossing for developing improved aromatic rice lines, while further selection is still required to stabilize key traits.
Unknown authors· Indian Journal of Agricultur...· 0 citations
These findings establish qPB10 as the primary locus governing Phytophthora blight resistance in sesame, and kompetitive allele-specific PCR (KASP) markers were developed based on sequence polymorphisms within the qPB10 interval that reliably discriminates resistant genotypes.
Jeongeun Lee, Eunyoung Oh, Sungup Kim et al.· BMC Plant Biology· 0 citations
Rice blast and bacterial blight are two major diseases that threaten rice production worldwide. Developing rice cultivars with both disease resistance and desirable grain quality is an important objective in modern rice breeding. In this study, R1179 carrying Pi2, Wxb and Alkb was crossed with IRBB7 carrying Xa7, Wxb and Alkb. Marker-assisted selection (MAS) was applied to an F2 population of 1123 plants, and a line, G163, combining Pi2, Xa7, Wxb and Alkb, was developed. Disease resistance evaluation showed that G163 retained the blast resistance conferred by Pi2 and the bacterial blight resistance conferred by Xa7, exhibiting resistance to the tested isolates of both pathogens. Grain quality assessment indicated that G163 possessed favorable milling, appearance and eating quality traits. Rapid Visco Analyzer (RVA) profiling further indicated desirable starch pasting properties. In conclusion, the rice line G163 carrying Pi2, Xa7, Wxb and Alkb was successfully developed through MAS. The results provide a useful germplasm resource for breeding rice cultivars with combined disease resistance and desirable grain quality.
Ruomin Wu, Zhi-Yin Zhou, Jiayang Li et al.· Agronomy· 0 citations
The aromatic rice cultivar Rojolele (Oryza sativa L. cv. Rojolele), prized for its superior organoleptic qualities, is highly susceptible to yellow stem borer (Scirpophaga incertulas), a pest causing significant yield losses in Asia. To address this vulnerability, we developed marker-free transgenic Rojolele lines expressing the cry1Ab gene using a double T-DNA vector system, eliminating reliance on antibiotic resistance markers. Agrobacterium-mediated transformation yielded 21 independent T0 lines, with PCR and Southern blot analysis confirming stable integration of cry1Ab in seven lines by the T3 generation. Immunostrip assays verified functional Cry1Ab protein expression, while bioassays demonstrated complete resistance in lines I.AR.4 and III.AR.5.3. Susceptible lines (I.AR.2, III.AR.5.2) exhibited variable transgene expressions, highlighting the importance of event selection. The marker-free strategy aligns with biosafety regulations, and the retained agronomic traits ensure compatibility with commercial cultivation. This study provides a sustainable solution to protect high-value aromatic rice, combining insect resistance with consumer-preferred qualities. Field trials and resistance management strategies, such as gene pyramiding, are recommended for future deployment.
Agus Rachmat, Enny Rimita Sembiring, A. N. Nurhasanah et al.· Journal of Genetic Engineeri...· 0 citations
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