Ranidhan is a popular late-maturing rice variety of Odisha state, India. The farmers of the state suffer heavy loss in years with flash floods as the variety is sensitive to submergence. Bacterial blight (BB) disease is a major yield-limiting factor, and the variety is susceptible to the disease. BB resistance genes Xa21, xa13, and xa5, along with the Sub1 QTL, for submergence stress tolerance were transferred into the variety using marker-assisted backcross breeding approach. Foreground selection using direct and closely linked markers detected the progenies carrying all four target genes in the BC₁F₁, BC₂F₁, and BC₃F₁ generations, and the positive progenies carrying these genes with maximum similarity to the recipient parent, Ranidhan, were backcrossed into each segregating generation. Foreground selection in the BC₁F₁ generation progenies detected all target genes in 11 progenies. The progeny carrying all target genes and similar to the recipient parent in terms of phenotype was backcrossed, and a total of 321 BC₂F₁ seeds were produced. Ten progenies carried all target genes/QTL in the BC₂F₁ generation. Screening of the BC₃F₁ progenies using markers detected 12 plants carrying the target genes. A total of 1270 BC₃F₂ seeds were obtained from the best BC₃F₁ progeny. Foreground selection in the BC₃F₂ progenies detected four plants carrying the target genes in the homozygous condition. The bioassay of the pyramided lines conferred very high levels of resistance to the predominant isolates of bacterial blight pathogen. These BB pyramided lines were submergence-tolerant and similar to Ranidhan in 13 agro-morphologic and grain quality traits; hence, they are likely to be adopted by farmers.

Reeta is a popular late-maturing high-yielding rice variety recommended for cultivation in the eastern Indian states. The cultivar is highly sensitive to submergence stress. Phosphorus deficiency is an additional constraint for realizing high yield. The quantitative trait loci (QTLs), Sub1, for submergence and Pup1 for low phosphorus stress tolerance along with narrow-grained trait, GW5 were introgressed into the variety from the donor parent, Swarna-Sub1 through marker-assisted breeding. In addition, phenotypic selections for higher panicle weight, grain number, and spikelet fertility were performed in each segregating generation. Foreground selection detected the 3 target QTLs in 9, 8 and 7 progenies in the BC₁F₁, BC₂F₁, and BC₃F₁ generation, respectively. Recurrent parent’s genome recovery was analyzed using 168 SSR polymorphic markers. The foreground analysis in 452 BC₃F₂ progenies showed five pyramided lines in homozygous condition for the target QTLs. No donor fragment drag was noticed in the Sub1 and GW5 QTLs carrier while a segmentwas observed in the Pup1 carrier chromosome. The developed lines were higher yielding, had submergence, and had low phosphorus stress-tolerance alongwith similar to the recipient parent in the studied morpho-quality traits. A promising pyramided line is released in the name of Reeta-Panidhan (CR Dhan 413) for the flood-prone areas of Odisha state.

Seed vigor is the key performance parameter of good quality seed. A panel was prepared by shortlisting genotypes from all the phenotypic groups representing seedling growth parameters from a total of 278 germplasm lines. A wide variation was observed for the traits in the population. The panel was classified into four genetic structure groups. Fixation indices indicated the existence of linkage disequilibrium in the population. A moderate to high level of diversity parameters was assessed using 143 SSR markers. Principal component, coordinate, neighbor-joining tree and cluster analyses showed subpopulations with a fair degree of correspondence with the growth parameters. Marker–trait association analysis detected eight novel QTLs, namely qAGR4.1, qAGR6.1, qAGR6.2 and qAGR8.1 for absolute growth rate (AGR); qRSG6.1, qRSG7.1 and qRSG8.1 for relative shoot growth (RSG); and qRGR11.1 for relative growth rate (RGR), as analyzed by GLM and MLM. The reported QTL for germination rate (GR), qGR4-1, was validated in this population. Additionally, QTLs present on chromosome 6 controlling RSG and AGR at 221 cM and RSG and AGR on chromosome 8 at 27 cM were detected as genetic hotspots for the parameters. The QTLs identified in the study will be useful for improvement of the seed vigor trait in rice.

Uptake of excess iron by lowland rice plants causes iron toxicity, which is a major problem in the affected areas. This study investigated molecular diversity, genetic structure, and marker–trait associations for tolerance to iron toxicity in a panel of germplasm lines using microsatellite markers. The studied population showed a moderate to high degree of genetic diversity, as revealed by the estimated molecular diversity parameters and principal component, cluster and box plot analyses. The landraces Mahipal, Dhusura, Dhabalabhuta, Champa, Sunapani and Kusuma were identified as suitable for cultivation in the areas affected by high iron levels. The landraces Dhusura, Kusuma, Kendrajhali, Ranisaheba, Panjabaniswarna, Mahipal, Dhinkisiali, Champa, Kalamara and Ratanmali, which showed low scores for tolerance, were considered good donors for iron toxicity tolerance improvement programs. Utilizing STRUCTURE software, a total of four genetic structure groups were detected in the panel germplasm of lines. These structural subgroups exhibited good correlations among their members for iron toxicity tolerance and other yield-related traits. Marker–trait association analysis validated the reported iron toxicity tolerance QTLs qFeTox 4.2 and qFeTox 4.3, which are useful for marker-assisted improvement. A new QTL, qFeTox 7.1, located on chromosome 7, was detected as controlling iron toxicity tolerance in rice.

The growth, physiology and yield stability of eggplants (Solanum melongena L.) are significantly impacted by excessive moisture stress during the reproductive stage, especially in humid and poorly drained settings. The goal of the current study was to categorise brinjal genotypes by their response patterns and to identify key phenotypic features associated with resistance to excess moisture stress. A completely randomized design (CRD) was used to assess 40 genetically distinct brinjal genotypes under controlled polyhouse conditions. At the onset of flowering, excess moisture stress was imposed for six consecutive days by maintaining continuous waterlogging with approximately 5 cm standing water above the soil surface, whereas control plants were irrigated to near field capacity without water stagnation. Leaf area (LA), number of leaves per plant (NL), root characteristics, total biomass (TB), Soil and plant analyser development (SPAD), chlorophyll content, canopy temperature (CT) and tolerance score were among the morphological and physiological characteristics recorded. Tolerance score showed a strong negative correlation with CT and positive correlations with LA, root length (RL), root volume (RV), root dry weight (RDW), NL and TB, as indicated by the correlation analysis. 83.6 % of the total phenotypic variance was explained by the first four principal components (PCs) in principal component analysis (PCA), with PC1 primarily reflecting an integrated growth vigour and tolerance axis. Divergent tolerance strategies were reflected in the classification of genotypes into susceptible (S), moderately tolerant (MT) and tolerant (T) groups using hierarchical cluster analysis. Under stress, T genotypes showed improved growth maintenance, strong root systems, advantageous physiological characteristics and reduced CT. Overall, the study provides reliable indirect selection criteria for breeding programs aimed at enhancing stress resistance and shows that coordinated morphological and physiological features, rather than a single attribute, govern tolerance to excess moisture stress in brinjal.