The Tamil Nadu Rice Research Institute (TRRI) is an Indian research institute working in the field of rice under Tamil Nadu Agricultural University (TNAU). Situated in Aduthurai, in Thanjavur district, it was established in April, 1985 in TNAU to meet the research requirements of the region with the help of existing Agricultural Colleges and Research centres and perform lead function for rice and rice based cropping system research. TRRI coordinate the research programmes of all the stations of the state on rice and rice based cropping system research. This directorate responsible for coordinating research in the Region II of the TNAU.
Blackgram (Vigna mungo L) is an important pulse crop in India, contributing significantly to dietary protein and nutritional security. Powdery mildew, caused by Erysiphe polygoni DC, is a major disease limiting blackgram productivity across diverse agroclimatic regions. This study investigated the pathogenic, morphological and molecular variability among ten naturally occurring E polygoni isolates collected from major blackgram growing areas of Tamil Nadu. The isolates showed noticeable variation in conidial size, hyphal growth, cleistothecia, asci and ascospore number, although traits such as ascus width and ascospore length remained relatively stable. ITSbased PCR amplification yielded a consistent ~ 630 bp fragment in all isolates, confirming species identity. Molecular analysis revealed high sequence similarity with only minor genetic differences among isolates. Overall, morphological variation was not closely associated with pathogenicity and ITS markers proved effective for species identification but limited for detecting intra-species diversity. The findings support improved pathogen characterization and provide useful information for developing durable powdery mildew resistance in blackgram.
Rice false smut, caused by Ustilaginoidea virens, is a major yield and quality limiting disease in humid rice ecologies. Breeding for durable resistance is constrained by limited stable genetic resistance sources, and is further complicated by pronounced genotype × environment interactions (GEI) and pathogen variability, which cause inconsistent field expression. We hypothesized that rigorous multi-environment evaluations using integrated multi-trait selection models could uncover stable resistance sources that do not compromise grain yield. To test this, an F₆ recombinant inbred line (RIL) population (n = 208) derived from crossing a high yielding susceptible variety (CO43) and a highly resistant donor (RG170) was systematically evaluated for agronomic performance and disease response. Initial screening revealed substantial genetic variability and high heritability (> 0.60). Consequently, 31 superior RILs were advanced to replicated multi-location trials across three distinct climatic environments. The evaluations revealed that GEI accounted for 53
Rice is a staple food crop feeding more than half of the global population, especially in Asia, where it dominates both production and consumption. However, rice cultivation is highly vulnerable to submergence stress caused by submergence, a phenomenon exacerbated by climate change. Submergence impairs oxygen diffusion, disrupts metabolism, and leads to massive yield losses. Despite this, rice possesses unique genetic and physiological traits enabling partial adaptation to this stress. Survival strategies, viz., quiescence (SUB1A-mediated) and escape (Snorkel genes-mediated), are the two primary mechanisms governing rice response to submergence. These responses are regulated by ethylene signaling, gibberellins and reactive oxygen species (ROS). Submergence-tolerant rice varieties optimize energy use, enhance anaerobic respiration, and develop specialized structures like aerenchyma and adventitious roots. Molecular breeding efforts, especially marker-assisted backcrossing (MABC), have introduced SUB1 genes into many high-yielding mega varieties like Swarna-SUB1 and IR64-SUB1. Meanwhile, germplasm exploration has revealed traditional and wild rice varieties with inherent submergence tolerance. Breeding strategies now integrate genomics, transcriptomics, and QTL mapping to develop flood-resilient varieties. Maintaining oxidative stress through the production of antioxidants also facilitates recovery following submergence. The multi-pronged approach combining genetics, physiology, and modern biotechnology is important for increasing rice productivity under intensifying submergence risks.
Root-knot nematodes (Meloidogyne incognita) are major constraints to tomato production, causing severe yield losses worldwide. The present study evaluated the biocontrol potential of four entomopathogenic nematode (EPN) species: Steinernema carpocapsae, S glasseri, S siamkayai and S feltiae against M incognita under in vitro and pot culture conditions. In in vitro assays, all Steinernema species significantly inhibited egg hatching, with S carpocapsae and S siamkayai showing the highest suppression, comparable to carbofuran. Pot culture experiments revealed that EPN treatments significantly improved plant growth and yield attributes while reducing nematode population, gall number and gall index compared to the untreated control. Among the EPNs, S carpocapsae was the most effective, followed by S siamkayai and S feltiae. The results demonstrate the potential of Steinernema species, particularly S carpocapsae, as eco-friendly alternatives to chemical nematicides for sustainable management of root-knot nematodes in tomato.
Dracaena reflexa Lam. ‘Song of India’ is a widely valued ornamental foliage plant recognized for its attractive variegation, durability, and air-purifying capacity. However, maximizing its commercial quality requires precise growth regulation. The present study was conducted to assess the impact of various plant growth regulators (PGRs) on the growth, yield, and quality attributes of D. reflexa under tropical conditions. The experiment was conducted using a Randomized Block Design with 16 treatments involving Naphthaleneacetic Acid (NAA), Triacontanol, Benzyl aminopurine (BAP), Forchlorfenuron (CPPU), and Brassinosteroids, applied as monthly foliar sprays. The results demonstrated that CPPU 500 ppm (T11) produced the most favourable response across multiple traits. This treatment significantly improved leaf breadth (3.21 cm), leaf area (53.59 cm²), stem girth (5.68 cm), chlorophyll content (55.91 SPAD), number of cut stems per plant (8.01), cut foliage yield per m² (22.18), visual quality score (9.79), and vase life (16.74 days), all markedly superior to the control. Triacontanol 75 ppm (T6 ) recorded the highest plant height (71.73 cm) and leaf length (19.76 cm), indicating its distinct role in promoting elongation growth. Overall, the study highlights CPPU 500 ppm as the most effective PGR for enhancing growth, aesthetic quality, and postharvest longevity in D. reflexa ‘Song of India’, offering a promising strategy for sustainable commercial cut foliage production.
