Acharya N. G. Ranga Agricultural University (ANGRAU) is a public agricultural university with its headquarters at the village Lam, Guntur district, Andhra Pradesh, India. G.
ABSTRACT Powdery mildew is a serious disease of sunflower in tropical and subtropical regions. A total of 221 genotypes—comprising Cytoplasmic Male Sterility lines, restorers, inbreds and stable interspecific recombinant inbred lines (IRILs)—were screened for field resistance to the disease. The IRILs, developed from a cross between the susceptible prebred line PS‐2023 and a resistant accession (PRA‐1823) of diploid annual species Helianthus praecox , displayed distinct and contrasting reactions to powdery mildew during the initial field screenings. Phenotypically superior susceptible and resistant IRILs, which also possessed multiple desirable agronomic traits, were further evaluated with artificial inoculation in greenhouse and multilocation field trials, along with established resistant and susceptible checks. Results indicated that the line PMS‐27 (PM‐1), previously classified as susceptible, consistently exhibited susceptibility across all locations. The percent disease index (PDI) of PMS‐27 ranged from 14.3% to 85.6% within 15 days post‐inoculation (dpi) with a conidial suspension, and disease progression continued, reaching a score of 9 by 45 dpi. In contrast, two resistant IRILs (PMR‐16 and PMR‐27) initially recorded low average PDIs of 4.8% and 5.3%, respectively, with no disease development further; these lines were scored as 0/1 at 45 dpi across all test locations. Previous studies from the authors' laboratory confirmed the presence of a dominant resistance gene in H. praecox and established the role of MLO (Mildew Locus O) genes in conferring susceptibility. The resistant and susceptible IRILs identified in this study therefore offer significant potential for advancing research on host–pathogen interactions and for developing durable powdery mildew resistance in sunflower.
Sesame is grown across two to three seasons in India, and productivity gains depend on broadening the crop’s narrow genetic base by identifying divergent parental lines. This study assessed genetic divergence among 200 sesame genotypes for 16 morphological and yield-related traits evaluated during Rabi 2024 (E1) and Kharif 2025 (E2), together with pooled data, at the Regional Agricultural Research Station, Tirupati. The experiment followed an alpha lattice design with two replications per season, and divergence was estimated using Mahalanobis D2 statistics with genotypes grouped by Tocher’s method. The 200 genotypes fell into 15 clusters in E1, 17 in E2, and 12 under pooled analysis. Inter-cluster distance exceeded intra-cluster distance in every case, confirming clear separation among groups. The widest divergence occurred between clusters XII and XV in E1, clusters VII and XIV in E2, and clusters IX and XI under pooled analysis. Thousand-seed weight, number of seeds per capsule, and oil content accounted for the largest share of total genetic divergence across environments. Twenty-nine genotypes retained consistent cluster membership across both seasons, and genotypes G112 and G158 recurred repeatedly among the most divergent clusters, marking them as strong candidate parents. Selecting parents on the basis of divergence that persisted across seasons proved more dependable than selection from a single season or from pooled means alone. These results point to specific, genetically distant genotype combinations that breeders can exploit for heterosis and transgressive segregation, and identify thousand-seed weight and seed number per capsule as efficient, low-cost traits for screening divergent germplasm in future sesame improvement programmes.
Nanoencapsulation of botanical insecticides has emerged as a promising strategy to improve the efficacy and stability of plant-derived compounds in stored-product pest management. The present study aimed to develop and evaluate nano silica-encapsulated formulations of neem (Azadirachta indica A. Juss.) oil, acorus (Acorus calamus L.) oil and the chemical insecticide imidacloprid for the management of Rhyzopertha dominica, a major pest of stored rice. Laboratory bioassays were conducted using contact toxicity and diet incorporation methods, followed by storage studies to assess long-term protective efficacy. The nano formulations were evaluated at different concentrations and adult mortality was determined using corrected mortality analysis. In contact toxicity assays, LC₅₀ values were 0.16 % for nano neem and nano acorus oils and 0.02 % for nano imidacloprid, compared with 0.17 %, 0.17 % and 0.03 %, respectively, for their conventional formulations. In the diet incorporation method, LC₅₀ values for nano neem, nano acorus and nano imidacloprid were 0.25 %, 0.26 % and 0.10 %, respectively, whereas conventional formulations recorded higher LC₅₀ values of 0.35 %, 0.47 % and 0.35 %. Storage studies revealed that nano silica-based formulations effectively protected rice seeds from insect infestation for up to five months without seed damage or weight loss. Furthermore, treated seeds maintained high germination percentage and seedling vigour throughout the storage period. The findings demonstrate that nanoencapsulation enhances the insecticidal efficiency and persistence of botanical oils while maintaining seed quality, highlighting its potential as a sustainable approach for protecting stored grains.
A field study was carried out during late rainy (kharif) season of 2022 and winter (rabi) season of 2022–23 at the Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu to explore the best nutrient management strategies for enhancing quinoa (Chenopodium quinoa Willd.) production. The experimental field was arranged in a randomised complete block design (RCBD) with nine treatments [T1, 75:0 kg N: K2O/ha; T2, 100:0 kg N: K2O/ha; T3, 125:0 kg N: K2O/ha; T4, 150:0 kg N: K2O/ha; T5, 75:50 kg N: K2O/ha; T6, 100:50 kg N: K2O/ha; T7, 125:50 kg N: K2O/ ha; T8, 150:50 kg N: K2O/ha and T9, Without N and K2O fertilisers (Control)], each replicated thrice. The results revealed that the application of 150:30:50 kg N: P2O5: K2O/ha (T8) led to superior growth parameters (plant height, leaf area index, dry matter production and number of branches/plant), yield attributes (number of panicle/plant, panicle length, panicle conversion efficiency, number of grains/panicle and test weight), yield (grain and stalk), and economic parameters (gross returns, net returns and benefit: cost ratio) for quinoa, outperforming other treatments except for 150:30:0 kg N: P2O5: K2O/ha (T4) during both seasons. The lowest values across all parameters were recorded for the control (T9). It can be inferred from the investigation that the application of 150:30:50 or 150:30:0 kg N: P2O5: K2O/ha significantly enhanced quinoa's growth, yield and economic parameters compared to lower nutrient doses in India.
