Jun 2026· Plant Breeding· 0 citations· 29 references
TL;DR
This mutant offers a prominent source of dwarfism and earliness for crop improvement in Indian mustard, and will be very useful as a source for ideotype breeding to develop early and dwarf/semi‐dwarf high‐yielding genotypes.
Abstract
Introduction of dwarfism to cereals has set a new paradigm in crop improvement programmes. To date, very little progress has been made in the development of high‐yielding dwarf/semi‐dwarf genotypes in oilseed
Brassica
. Previous attempts using induced mutagenesis employed in the induction of dwarfism in
Brassica
crops yielded limited success, and many mutants had markedly unfavourable modifications in the plant. In the present study, we characterised a gamma radiation–induced dwarf and early mutant,
Trombay juncea dwarf‐1
(
tjd1
), in Indian mustard,
Brassica juncea
cv. Varuna, that showed improved yield‐contributing traits like total siliquae number and number of branches. This mutant offers a prominent source of dwarfism and earliness for crop improvement in Indian mustard,
B. juncea
. Nature of dwarfism in
tjd1
was assessed in terms of major components of plant architecture contributing to plant height. The mutant showed about 45.09% reduction in plant height compared to the parent cultivar due to the reduction in the height of the first branch, length of main fruiting axis and number and length of the internodes. At anatomical level, mutant
tjd1
showed reduction in both cell size and number of cells/mm. The genetic analysis using F
1
, F
2
and BC
1
F
1
populations indicate that the dwarf plant height is controlled by a single recessive gene with incomplete dominance. The mutant responded towards auxin treatment at both seedling and late vegetative phase and also showed significant downregulation of the key genes involved in phytohormone pathways. Overall, the
B. juncea
mutant
tjd1
will be very useful as a source for ideotype breeding to develop early and dwarf/semi‐dwarf high‐yielding genotypes.
Bread wheat (Triticum aestivum L.) is a major staple crop providing essential calories for human diets. However, intensive breeding for yield has reduced genetic diversity for quality traits, including grain protein content (GPC). Induced mutagenesis offers an effective strategy to broaden the genetic base and generate novel alleles affecting agronomic traits. In this study, M₅ mutant lines of the spring wheat cultivar Eritrospermum-35 were developed through gamma irradiation at 100 Gy and 200 Gy. Lines were evaluated for variation in GPC and days from sowing to heading under controlled greenhouse conditions. GPC was measured using near-infrared reflectance spectroscopy (NIR), and allelic variation at the candidate gene Eps-Am1 was analyzed using PCR-based markers. Substantial variation in GPC was observed. The 100 Gy lines showed GPC values ranging from 12.60% to 14.43% (mean 13.56 ± 0.57%), whereas the 200 Gy lines had a mean GPC of 13.76 ± 0.63%. Eleven mutant lines (37%) exhibited significantly higher GPC (5.7–11.0%) than the parent. Importantly, the increase in GPC was not associated with a reduction in thousand kernel weight; TKW values were higher in irradiated lines compared with the parent. Days to heading differed between treatments: 100 Gy lines headed earlier, while 200 Gy lines showed delayed heading. Molecular screening identified new alleles of Eps-Am1, with allele carriers generally exhibiting earlier heading. Overall, gamma irradiation generated valuable genetic variation for improving grain protein content and adaptive traits in spring wheat.
Key words: gamma irradiation, grain protein content, days to heading, thousand kernel weight, spring wheat, Eps-Am1, mutation breeding.
G. Doktyrbay, S. Kenzhebayeva, S. Atabayeva et al.· International Journal of Bio...· 0 citations
BACKGROUND
Polyploidy is a major driver of plant evolution and crop improvement, generating novel variation in morphology, physiology, and agronomic traits. Brassica juncea (AABB, 2n = 36), a natural allotetraploid derived from B. rapa (AA) and B. nigra (BB), is an important oilseed and vegetable crop; however, its narrow genetic base limits further breeding gains. Resynthesized B. juncea (RBJ), developed from known progenitors, provides a tractable system to investigate polyploid stabilization, trait diversification, and generational variation. This study evaluated RBJ across nine generations (F1-S8) to elucidate generational variation in morphological, molecular, cytological, and oil content traits during progressive stabilization.
RESULTS
Substantial variation was observed for key yield-related traits, including siliqua length, seeds per siliqua, and thousand-seed weight. High estimates of heritability, genotypic variance, and genetic advance indicated their potential utility in selection based improvement. Comparative analyses revealed a clear generational progression, characterized by relatively enhanced performance in early generations, increased recombination-driven variability in intermediate generations, and the partial stabilization of several traits in later generations. Generation mean analysis suggested the involvement of additive, dominance, and epistatic gene effects in trait inheritance. Molecular analysis using SSR markers confirmed the amphidiploid origin and genomic integrity of RBJ generations. Cytological assessments, pollen viability assays, and flow cytometric analysis collectively demonstrated stable chromosome numbers, improved fertility, and maintenance of ploidy stability across successive generations.
CONCLUSIONS
The study provides valuable insights into the generational variation and stabilization of morphological, molecular, and oil content traits in resynthesized B. juncea. The findings suggest that variability arising from polyploidization and interspecific hybridization undergoes gradual reorganization across successive generations, leading to increased trait stabilization and more consistent expression of selected agronomic characteristics. Collectively, these results contribute to the understanding of early stabilization processes in RBJ, highlighting resynthesized polyploids as useful systems for studying variation and stabilization in allopolyploid crops.
Developing high-yielding and water-stress-tolerant bread wheat cultivars with high water productivity is vital for sustainable wheat cultivation under the limited water resources in Egypt. In this study, bread wheat mutant lines from the M3, M4, and M5 generations and their mother cultivars were evaluated under both well-watered and limited-irrigation conditions over three growing seasons (2022–2024). Eight agronomic traits and water productivity were estimated to detect high-yielding, water stress-tolerant wheat lines with improved water productivity. Significant differences (p ≤ 0.05) were observed among the mutant lines for the studied traits under both conditions. Twelve selected mutant lines surpassed their mother cultivars. Mutant line G5 exhibited the shortest plant height with high potential yield, representing a dwarf phenotype. Mutant lines G10, G1, G2 and G4 exhibited the highest actual genetic gain relative to the highest-yielding mother cultivar. High broad-sense heritability coupled with moderate to high genetic advance for the studied traits indicated the predominance of additive gene action and confirmed the effectiveness of phenotypic selection. Drought tolerance indices selected the same promising lines under limited-irrigation conditions. GGE biplot analysis revealed that mutant lines G2, G3, G4, G5 and G6 were superior high-yielding lines, whereas G4, G7, G10 and G11 exhibited greater stability across irrigation regimes. Selected mutant lines exhibited improved water productivity compared with their mother cultivar under both conditions. Selected putative mutant lines will be advanced to multi-environment trials to further evaluate genotype x environment interactions and genetic stability. These mutant lines could serve as valuable genetic resources for bread wheat breeding programs aimed at enhancing grain yield under water-limited conditions.
Drought tolerance is an important breeding objective for improving the yield of cereal crops. Identifying key drought-tolerant loci/genes from Setaria viridis and Setaria italica is essential for enhancing the yield and stress resistance of foxtail millet via molecular breeding technologies. Here, an interspecific recombinant inbred line (RIL) population was constructed by crossing the S. italica cultivar Yugu1 with the wild S. viridis H1. Phenotypic evaluation and QTL mapping for drought tolerance were conducted from the grain filling to the maturity stage. Five strong drought-tolerant lines were screened using the drought resistance index (DRI). Phenotypic variance analysis indicated that the period of duration was the key factor affecting drought tolerance in the population. Furthermore, the RIL population was subjected to whole-genome sequencing, and a high-density linkage map was constructed, comprising 3,029 bin markers spanning 709.34 cM with an average interval of 0.24 cM. A total of 10 QTLs were detected for panicle number per plot (PNP), grain weight per plant (GWP), and 1000-grain weight (TGW). Eight QTLs were associated with PNP, and the favorable alleles at all loci except qPNP4.1 were derived from Setaria viridis H1. The favorable alleles of the other two QTLs for GWP and TGW were all from Yugu1. Based on functional homology alignment, five genes located within three PNP-related QTL intervals (Seita.5G420900, Seita.7G306400, Seita.5G312700, Seita.5G319000, Seita.5G319500) were predicted to modulate the tillering, grain yield under drought stress conditions. These findings provide an important basis for drought-tolerant breeding and the dissection of the drought tolerance mechanisms in foxtail millet and its close species.
This article presents the results of a comprehensive assessment of the manifestation of true and competitive heterosis in spring rapeseed (Brassica napus L.) hybrids that were developed using the Polima cytoplasmic male sterility system. The studies were conducted under the forest-steppe conditions of the Central Chernozem region of Russia in 2024–2025. The study subjects included F1 hybrids, sterile maternal lines with the Polima CMS system, fertility restorer lines (Rf lines), and the standard variety Ratnik. The evaluation was based on key economically important traits that determine seed productivity and biochemical seed characteristics, such as the pod number per plant, seed weight per plant, oil content, and protein content. The manifestation of heterosis was found to vary depending on the hybrid combination and trait analyzed. The LHS-1 × HYFR-2 (S2) hybrid exhibited the most pronounced positive true and competitive heterosis in terms of pod number and seed weight per plant, with true heterosis values reaching 30.5–32.5%. The degree of phenotypic dominance indicated superdominance of the traits. In terms of oil content, this hybrid also outperformed the parent lines, reaching 44.3%. The maximum protein content (up to 29.1%) was observed in the Sample No. 5 × HYFR-2 (S2) hybrid combination. These results demonstrate the potential for using the Polima CMS system in developing spring rapeseed hybrids and for identifying parent material for further breeding work.
Indian mustard (Brassica juncea L.) is an important oilseed crop contributing substantially to India’s edible oil production. The present investigation was undertaken to assess genetic variability among 30 Indian mustard genotypes evaluated for twelve quantitative traits. In Rabi, 2023–2024, the experiment was carried out at the Instructional Farm, Sri Karan Narendra College of Agriculture, Jobner, Jaipur, using a randomised block design with three replications. Significant differences between genotypes for every variable were found by analysis of variance, suggesting that there is sufficient genetic variability. The number of branches per plant showed moderate phenotypic variation (10 to 20 %), whereas the number of siliquae per plant and seed output per plant showed high phenotypic and genotypic coefficients of variation (>20 %). The majority of the remaining characteristics showed little phenotypic and genotypic coefficients of variation (<10 %). Plant height, days to maturity, oil content, days to 50 per cent flowering, siliquae per plant, seed production per plant and chlorophyll content all showed high heritability estimates, indicating little environmental influence. For certain traits, substantial heritability and moderate genetic advancement suggested that both additive and non-additive gene activity were involved, underscoring their value in selection for increased yield. Selection for traits exhibiting high heritability and genetic advance may facilitate the development of high-yielding Indian mustard varieties. Promising genotypes identified in present investigation may be employed in pedigree breeding, disruptive mating and recurrent selection breeding programme to combine favourable yield attributes in future Indian mustard cultivars.
Anchal Agarwal, Ram Kunwar, Deepak Gupta et al.· Electronic Journal of Plant...· 0 citations