Terminal drought stress severely reduces wheat productivity in arid and semi-arid regions by limiting water availability during critical reproductive stages of flowering, grain setting, and grain filling. Understanding the genetic basis of drought tolerance is therefore essential for developing effective wheat breeding strategies. We evaluated six generations (P1, P2, F1, F2, BC1, and BC2) derived from the Barat × Nogal cross under normal irrigation and terminal drought-stress field conditions. Generation mean analysis was used to estimate additive, dominance, and digenic epistatic gene effects for agronomic and physiological traits. Water regime significantly affected peduncle length, days to maturity, 100 grain weight, grain yield per plant, flag leaf area, SPAD chlorophyll index, total chlorophyll, and proline concentration, whereas generation effects were significant for all evaluated traits. Significant joint scaling tests under both water regimes showed that the additive–dominance model was inadequate, indicating the involvement of epistatic interactions in trait inheritance. Dominance effects were broadly important, and dominance × dominance epistasis contributed substantially to yield-related traits. Under terminal drought stress, additive effects were significant for several morphological and physiological traits, whereas grain yield and grain number were predominantly controlled by non-additive effects. Peduncle length, flag leaf area, plant height, days to maturity, and carotenoid concentration exhibited high narrow-sense heritability under terminal drought stress, suggesting their potential for effective selection.
Enhancing oil quality and disease resistance in Indian mustard (Brassica juncea L.) is critical for ensuring nutritional safety and stable productivity. Marker-assisted backcross breeding was implemented to transfer the low-erucic acid trait from the donor genotype PDZ-1 into the elite but high-erucic cultivar NRCDR-601, followed by simultaneous selection for white rust resistance. Trait-linked markers FAE1.1 and FAE1.2 were evaluated for polymorphism and utilized for foreground selection, while background recovery was assessed using 77 polymorphic SSR markers. Recurrent parent genome recovery increased progressively from 79.87
St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) is a widely used warm-season turfgrass valued for its adaptability and persistence in warm and subtropical climates. However, many cultivars exhibit relatively coarse leaf texture, which limits turf quality and reduces their acceptance for landscape use. Mutation breeding offers a promising approach for generating novel genetic variation and improving turf quality traits. In this study, gamma irradiation–derived mutant lines of St. Augustinegrass were evaluated over multiple years under Mediterranean field conditions to assess turf performance, stolon morphology, and environmental adaptation. Several mutant genotypes exhibited improved visual turf performance compared with the parental control, including darker canopy color, finer leaf texture, increased turf density, higher turf quality, and improved winter color retention. Many mutants also displayed compact stolon architecture characterized by shorter internodes (up to 35
The growing demand for dehydrated onion products has intensified the need for cultivars specifically tailored for industrial processing. Unlike fresh-market onions, processing cultivars require a unique combination of traits, including high dry matter content, elevated total soluble solids, desirable pungency, superior storability, bulb uniformity, and enhanced processing recovery. However, the development of such cultivars remains challenging because onion (Allium cepa L.) is a biennial, highly heterozygous, cross-pollinated crop with severe inbreeding depression and a large ( 16.4 Gb), repeat-rich genome that complicates genome assembly, limits marker development, and hinders marker-assisted selection. This review synthesizes recent advances in the genetic improvement of processing-quality traits by integrating knowledge from conventional breeding, molecular genetics, genomics, genome-wide association studies, quantitative trait locus mapping, and genome-editing technologies. The influence of agronomic practices, nutrient management, irrigation, harvest maturity, curing, and storage on processing quality is also discussed, highlighting their interactions with genetic factors in determining bulb composition and postharvest performance. In addition, recent developments in high-throughput phenotyping, marker-assisted breeding, genomic selection, and CRISPR/Cas-based genome editing are critically evaluated for their potential to accelerate the development of processing-oriented cultivars. Current research gaps, including the limited availability of elite processing germplasm and trait-linked molecular markers, are identified, and future breeding strategies integrating genomics, precision phenotyping, and advanced biotechnology are proposed. This review provides a comprehensive framework for improving onion processing quality and supports the development of cultivars that meet the evolving requirements of the global dehydration industry.
Among the various abiotic constraints, aluminum (Al) toxicity significantly limits crop productivity in acidic soils. Genetic improvement for Al tolerance is a promising approach to boost the productivity of diverse field crops, including sunflower (Helianthus annuus L.), under such conditions. The availability of Al tolerant sunflower germplasm is limited, and the genetic mechanisms, particularly the number of genes and their mode of action conferring Al tolerance in this crop, remain uncharacterized. To gain insights into inheritance patterns, two Al tolerant genotypes (NDLR-06 and EC-601861) were crossed with susceptible genotypes (MR-06 and RHA-298). Seedlings of parental lines (P1 and P2) and their F1, F2, and backcross (BC1P1 and BC1P2) progenies were phenotyped in a nutrient solution containing 1.5 ppm Al concentration with pH 4.5. Following staining with Eriochrome Cyanine R, root regrowth, a dependable indicator of Al tolerance was used to distinguish Al tolerant and susceptible seedlings. Segregation patterns in all the crosses were analyzed to assess the inheritance of Al tolerance. Our results clearly indicated that Al tolerance is primarily governed by a single dominant gene, with the possible contribution of minor genes. Generation mean analysis (GMA) further revealed that additive, dominance, and epistatic gene effects play an important role in the quantitative expression of Al tolerance in sunflower. For root regrowth (RRG), the higher estimates of dominance variance compared to additive variance across all crosses suggested that non-additive gene effects, particularly the dominance effects, are crucial contributors to the genetic control of this trait, whereas total root length (TRL) was predominantly governed by additive gene effects, with dominance variance exceeding the additive component only in Cross I. The moderate to high heritability (broad- and narrow-sense) obtained for both RRG and TRL traits suggests that Al tolerance in sunflower can be improved through breeding and selection. In conclusion, breeders should consider both major and minor gene effects when designing breeding strategies for Al tolerance in sunflower.
