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.
Efficient multi-trait selection across cropping cycles is essential for accelerating the genetic gain in the sugarcane breeding pipeline. However, limited studies have integrated REML/BLUP-based genetic parameters, and the multi-trait genotype ideotype distance index (MGIDI) approaches in sugarcane breeding for identification of candidate clones in terms of cane and sugar yield trait combination under diversified cropping cycles. The present study evaluated 28 sugarcane clones across three cropping cycles: Plant Crop I (2022–2023), Plant Crop II (2023–2024), and Ratoon (2023–2024) at RARS, Anakapalle, to identify high-yielding and stable clones. Except for cane length, all yield and sugar quality traits exhibited significant genetic variation and genotype × season interaction at the p ≤ 0.05 level. The REML/BLUP analysis revealed moderate heritability and high selection accuracy for CCS yield, identifying it as the most reliable trait for direct genetic improvement in sugarcane breeding. Principal component analysis explained 84.4
Insecticide resistance complicates pest management by reducing chemical effectiveness and increasing environmental pollution from higher application rates. Monitoring resistance is essential before recommending chemicals in any agro-ecological region. The present study evaluated the extent and mechanisms of insecticide resistance in the cotton leafhopper, Amrasca biguttula biguttula (Ishida) (Hemiptera: Cicadellidae), across major cotton-growing regions of Maharashtra, India over five consecutive years, from 2015-16 to 2019-20 at ICAR-Central Institute for Cotton Research (CICR) in Nagpur. The bioassay studies using IRAC protocols revealed that populations collected from the Amravati district of Maharashtra exhibited higher LC50 values for all tested insecticides, including Flonicamid 50WG, Thiamethoxam 25WG, Acetamiprid 20SP, Imidacloprid 17.8SL, Monocrotophos 36SL, Acephate 75SP, Clothianidin 50WDG, and Spiromesifen 22.9SC. The tentative discriminating doses were established based on a susceptible population of A. biguttula at 1, 0.2, 0.05, 0.01, 0.001, 0.0001, and a control of 0 ppm. Using standardized IRAC bioassay protocols, we assessed resistance levels for eight insecticides and noted significant increases in LC50 values. Notably, the A. biguttula biguttula populations from Yavatmal, Chandrapur, and Amravati exhibited critical resistance to neonicotinoids and other classes of insecticides. Biochemical assays revealed elevated activities of detoxifying enzymes, including cytochrome P450 monooxygenases, carboxylesterases, and glutathione S-transferases (GST), indicating metabolic resistance as a key mechanism. Notably, Amravati populations displayed the highest enzyme activities (e.g., GST up to 555.56 pmol/min/mg protein), correlating with intense insecticide use. These findings emphasize the need for integrated pest management (IPM) strategies, including insecticide rotation, biological controls, and resistant cotton hybrids, to mitigate insecticide resistance and minimise environmental impact. Regular monitoring of resistance and enzyme activity is essential for sustainable pest control in cotton ecosystems.
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.
