Future Projections of Rainfall for Tamil Nadu from Coupled Model Intercomparison Project- 6 (CMIP6)

Precipitation is a crucial input for agriculture and living things in the world, which changes drastically under a warmer climate due to climate change. Hence, the study was carried out to project the changes in annual and seasonal precipitation based on the France Centre National de Recherches Météorologiques (CNRM-CM6) model. In the present study, Coupled Model Intercomparison Project phase six (CMIP6) datasets were used for two SSP scenarios: SSP2-4.5 and SSP5-8.5 and three-time slices for the future viz., near (2021–2050), mid (2051–2080) and end-century (2081–2099) and base period (1991–2020) dataset obtained from the India Meteorological Department (IMD) was used to compare with the future climate over Tamil Nadu. The result revealed that the highest positive mean deviations in annual (81%), SWM (21%), NEM (79%) and summer (163%) were observed in the projected precipitation under the SSP5-8.5 scenario during the Near, mid, near and mid-century respectively. For winter, SSP2-4.5 showed the highest mean deviation of 122% in the near century. According to the three future time scale simulations for the twenty-first century, annual rainfall is predicted to increase by 81% in the near future and 19% in the mid-century, while it is expected to decline by 1.5% at the end of the century under SSP5-8.5. In the SSP2-4.5 scenario, rainfall would increase by 1% in the near future, decrease by 30% in the end century and decrease by 30.5% in the mid-century. From the result, it is concluded that there would be an increase in heavy precipitation occurrences at the near, mid and end of the 21st century under both the SSP5-8.5 and SSP2-4.5 scenarios. These findings might be helpful in framing future agricultural water management regulations to deal with threats from heavy precipitation and researchers to study precipitation changes at the global level.

Identification of Contrasting Parents and Development of Mapping Population for Sucking Pest Resistance in Cotton

The current study was conducted to identify the best parents with good agronomical features and contrasting characteristics for sucking pest resistance to develop a population that can be used for Quantitative Trait Loci mapping of resistance component traits. Initial attempts at this university have enabled to identify of five potential parents (viz., KC3, NDLH 1938, CO18, K12, and RG8) with improved sucking pest resistance and yield characters and they were crossed with the recently released high-yielding variety CO-17, which is also suitable for high-density planting. All these six parents were evaluated for fiber yield and quality traits besides anatomical characters such as trichomes density, length, width, and sharpness that confers sucking pest resistance and genotyped with 200 Simple Sequence Repeats markers that span the entire genome. Efforts have been dedicated to the careful selection of optimal parents, namely CO17 and KC3, each possessing distinct traits related to resistance against sucking pests and also fiber quality characters in addition. This strategic approach aims to combine their contrasting genetic components for sucking pest resistance, to develop a new generation of plants that exhibit heightened resilience to these types of pests. CIR139, a polymorphic SSR marker of these two parents was used to fix the true hybrids which were advanced to generate an F2 mapping population. This population is believed to be useful for QTL mapping of anatomical features that confer sucking pest resistance such as trichome length, density, breadth, and sharpness besides fiber yield and quality traits.

Optimizing Nursery Trays for Minimizing Seedlings per Pick of Transplanter in SRI

The System of Rice Intensification (SRI) revolutionizes rice cultivation through innovative practices. It is a methodology that enhances rice yields by optimizing plant growth and resource utilization. This study, conducted in 2023 at TNAU, Coimbatore, India, focuses on the optimization of nursery tray configurations for enhanced seedlings per pick during rice transplantation, contributing to more efficient SRI cultivation. The selection of nursery trays plays a crucial role in determining seedling distribution, impacting crop yield and agricultural efficiency. Through the manipulation of seed density, depth of filling, and tray configuration, the research aims to improve the seedlings' per-pick outcome during mechanized transplantation. The investigation involves 12 tray combinations with varying seed density (40 gm, 60 gm, 80 gm, and 100 gm) and depth of fillings with different heights in tray (15 mm, 20 mm, and 25 mm). Seedling growth parameters are meticulously assessed, including shoot length and root length to evaluate tray efficacy. The study also analyzes transplanter compatibility and the influence of seed density and depth of filling on seedling growth. Results highlight the tray configuration with an 80 gm seed density and 25 mm soil height as optimal, offering 1-3 seedlings per pick and minimal missing hills less than 1%. The endeavor to minimize picks per hill through precise tray combinations represents a crucial step in addressing the challenges of modern agriculture and shaping a more sustainable and productive future.