It is suggested 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.
Abstract
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.
Bhut Jolokia (Capsicum chinense Jacq.), also known as ghost pepper, is recognised for its extreme pungency and its bioactive compounds produced by the plant that may have medicinal potential. Because cultivation relies mainly on farmer-saved seeds or plantlets, generational variation in traits is poorly understood. This study tracked two progenies (A3 and A4, which are offspring derived from different parent plants) to address this gap. The second generation (G2) consistently outperformed the first (G1) and third (G3) generations in germination (77.08–90.32 % germination percentage, mean time 18.5–19.0 days and higher seedling vigour), vegetative, reproductive and yield traits (p < 0.05), established an order of G2 > G1 > G3 for all traits measured. The G3 showed greater variability in germination, indicating reduced vigour uniformity. Correlation analysis confirmed strong links between yield and fruit number (A3: r = 0.935; A4: r = 0.941; p < 0.01), total flower number and plant height. Principal component analysis revealed that most phenotypic variance (over 72 % of the differences in plant characteristics) in both lineages was due to reproductive and yield traits. In A3, the first principal component (PC1, accounted for 44.32 % of the variation) emphasised fruit number, flowers, yield and height; the second (PC2, 29.74 %) emphasised fruit weight. In A4, PC1 (48.41 %) included fruit number, yield and flowers; PC2 (24.45 %) included fruit weight and height.
B. Mitali, B. Minakshi, C. Robinson et al.· Plant Science Today· 0 citations
Onion (
Allium cepa
L.) is the second most commonly produced and consumed vegetable worldwide. In West Africa, high heat and moisture are key constraints for onion productivity during the rainy-season. This study aimed to assess the combining ability, heterosis, and genetic variability of five onion genotypes and 10 F
1
hybrids generated through a half diallel mating design to identify superior parental lines and hybrids adapted to heat and moisture conditions.
The experiment involved five parents: Prema 178, EW001, Violet d’Abéché, Violet de Galmi and AC980. The trials were implemented on station at the World Vegetable Center in Samanko by using a randomized complete block design. Twelve morphological, physiological, and agronomic traits were evaluated.
Analysis of variance showed substantial genetic variability. Significant general combining ability (GCA) and specific combining ability (SCA) effects indicated that both additive and non-additive gene actions influence key traits. The best general combiner was Parent P1 (Prema 178), which had the best positive GCA effects on plant survival rate (5 and 4.98), plant height (2.36 and 2.53), number of bulbs (5.82 and 3.38), and bulb yield (2.09 and 2.44). The hybrids P4×P5 (Violet de Galmi x AC980) and P1xP5 (Prema 178×AC980) had the most positive SCA effects and the best heterosis values over the midparent (105.26%) and better parent (94.56%) for bulb yield, as well as strong vigor and root growth.
These results demonstrate that the hybrids P4×P5, P1×P5, and P3×P5 are good candidates for multilocation testing in high heat and high moisture prone conditions.
A. Traore, J. Tignégré, Z. Kiébré et al.· Frontiers in Horticulture· 0 citations
Rice (Oryza sativa L.) is the primary staple food for more than half of the world's population, making the development of high-yielding cultivars essential for global food security. The present study evaluated genetic variability, heritability, genetic advance, character associations, and principal components in an F₂ segregating population comprising 133 individual plants derived from the cross NPA-109 × DRR Dhan 74. The population was evaluated during Kharif 2025 at the research farm of the ICAR–Indian Institute of Rice Research (ICAR-IIRR), Hyderabad. Five quantitative traits—plant height, number of tillers per plant, productive tillers per plant, panicle length, and grain yield per plant—were recorded. Phenotypic and genotypic coefficients of variation, broad-sense heritability, genetic advance as a percentage of the mean, Pearson's correlation, and principal component analysis were used to assess the genetic architecture of the population. The phenotypic coefficient of variation was consistently slightly higher than the genotypic coefficient of variation, indicating minimal environmental influence on trait expression. High heritability coupled with high genetic advance was observed for grain yield per plant, productive tillers, and number of tillers, suggesting the predominance of additive gene action and the potential effectiveness of direct selection. Correlation analysis and principal component analysis identified panicle length and productive tillers as important contributors to grain yield. Continuous frequency distributions further indicated quantitative inheritance and extensive genetic recombination within the population. Superior transgressive segregants, particularly DBN-25-2-1 and DBN-25-7-10, exhibited high grain yield and represent valuable breeding material for advancement to subsequent generations and the development of high-yielding rice cultivars.
Naresh Kumar Sahu, D. Gauraha, A. Sao et al.· Journal of Advances in Biolo...· 0 citations
Linseed (Linum usitatissimum L.) is an important oilseed crop in which improvement of seed yield depends on the availability of genetic variability and the identification of useful yield-associated traits. The present investigation was undertaken to assess genetic variability, heritability, genetic advance, correlation and path relationships for ten quantitative traits in 40 linseed genotypes. The experiment was conducted during rabi 2024–2025 at the College of Agriculture, Latur, Maharashtra, India, in a randomised block design with two replications. The traits evaluated included days to 50% flowering, days to maturity, plant height, number of branches per plant, number of capsules per plant, number of seeds per capsule, 1000-seed weight, oil content, harvest index, and seed yield per plant. Analysis of variance revealed significant differences among the genotypes for all the assessed traits.The recalculated estimates showed that GCV ranged from 4.61% for days to maturity to 22.15% for number of branches per plant, while PCV ranged from 5.14% for harvest index to 22.53% for number of branches per plant. Broad-sense heritability ranged from 63.06% for days to maturity to 98.24% for harvest index. Genetic advance as a percentage of the mean was highest for number of branches per plant (44.86%), followed by oil content (35.74%), 1000-seed weight (28.49%), number of capsules per plant (26.80%), number of seeds per capsule (26.16%) and seed yield per plant (25.96%). At the genotypic level, seed yield showed positive associations with number of branches per plant (0.7118), number of capsules per plant (0.7044), number of seeds per capsule (0.7265), plant height (0.0073) and 1000-seed weight (0.0141). The reported path analysis indicated positive direct effects of number of seeds per capsule (0.8083) and number of capsules per plant (0.3397) at the genotypic level, while number of branches per plant showed a high positive direct effect at the phenotypic level (1.6152). Thus, number of branches per plant, number of capsules per plant and number of seeds per capsule may be considered important selection criteria for improving seed yield under the present experimental conditions. The study was conducted at one location in one season; therefore, further multi-location and multi-season evaluation is necessary.
Aims: To evaluate the combining ability, determine the nature of gene action governing yield, oil content and associated traits, and identify superior parents and promising hybrid combinations for sunflower (Helianthus annuus L.) improvement.
Study Design: Line × tester mating design.
Place and Duration of Study: Oilseeds Research Station, Latur, Maharashtra, India, during kharif 2025 (hybrid development) and rabi 2025–26 (field evaluation).
Methodology: Six cytoplasmic male sterile (CMS) lines and seven restorer lines were crossed in a line × tester mating design to generate 42 hybrids. The resulting hybrids, along with their 13 parents and three standard checks, were evaluated in a randomised block design with two replications for ten agro-morphological and quality traits. Data were subjected to analysis of variance, line × tester analysis to estimate general and specific combining ability, and assessment of gene action following the method of Kempthorne (1957).
Results: Analysis of variance revealed highly significant differences among the genotypes for all the traits studied, indicating substantial genetic variability. Line × tester analysis showed significant GCA and SCA effects for most traits, with non-additive gene action predominating for seed yield and several associated traits. Among the parents, NDCMS 2A and CMS 597A were identified as good general combiners among the lines, while NDL20, NDL3 and GMU847 were the most desirable testers for seed yield, oil content and associated traits. The crosses NDCMS 2A × NDL20, CMS 597A × NDL20, CMS 597A × NDL3, CMS 852A × GMU847 and CMS 597A × HOCL-20R exhibited desirable specific combining ability effects coupled with superior per se performance, indicating their potential for exploitation in sunflower hybrid breeding.
Conclusion: The findings indicated the involvement of both additive and non-additive gene action in the inheritance of yield, oil content and associated traits in sunflower, with the predominance of non-additive gene action for most of the characters. The identified superior combiners and promising hybrid combinations provide valuable genetic resources for the development of high-yielding and high-oil sunflower hybrids and can be effectively utilised in future sunflower breeding programmes.
Surya Prakash Sharma, M. V. Dhuppe, S. Pole et al.· Plant cell biotechnology and...· 0 citations
Polyploidy is widely used in plant breeding to increase phenotypic variation and potentially improve stress-related traits; however, its effects in common bean remain poorly characterized. Here, colchicine-induced polyploidy was evaluated in Phaseolus vulgaris cv. Zorzal to determine whether tetraploid lines exhibit coordinated changes in stomatal anatomy, physiology, pigment composition, oxidative balance, and ploidy inheritance. Polyploidy was induced using different colchicine exposure regimes and confirmed by flow cytometry. Stomatal traits, gas-exchange parameters, photosynthetic pigments, oxidative stress markers, antioxidant capacity, and multivariate phenotypic relationships were subsequently analyzed in confirmed tetraploid lines. Colchicine treatments successfully generated tetraploid and mixoploid plants, although induction efficiency was highly variable among replicates. Tetraploid lines showed heterogeneous physiological responses, including increases in the photosynthetic rate and stomatal conductance in some genotypes, but no consistent reduction in stomatal pore area index. Pigment composition and antioxidant-related traits also varied among lines, without a uniform response pattern. Multivariate analyses revealed coordinated but highly divergent phenotypic profiles among tetraploid genotypes. Importantly, the induced tetraploids were not stably transmitted to the C1 generation, with a predominance of diploid progeny among the evaluated offspring. Overall, colchicine-induced polyploidization generated substantial physiological variability among independently derived tetraploid plants of P. vulgaris cv. ‘Zorzal’; however, the predominance of diploid individuals among the evaluated C1 progeny indicates limited transmission of the induced tetraploid state to the subsequent generation.
V. Martínez-Barradas, Gabriela Olivo-Vidal, R. Mora-Sanhueza et al.· Plants· 0 citations