G×E analysis to Identify the Stable High-yielding Rice Lines among a Set of Selected Germplasm Panel

Rice lines need to be grown and evaluated for yield under different agro-ecological locations to identify stable and high-yielding lines for deployment in breeding programs. With this aim, a set of rice germplasm was evaluated for G×E in four different environments (E1-Dadesuguru-Wet 2020, E2-ICAR–IIRR-Dry 2019, E3-ICAR–IIRR-Wet 2020, E4-ICAR–IIRR-Dry 2020). The experimental trial was laid out in a randomized complete block (RCB) design with three replications at each location for 118 rice lines. Data on yield per plant was analyzed using the Additive Main Effect and Multiplicative Interaction (AMMI) and Genotype, and Genotype × Environment Interaction (GGE) models. The combined analysis of variance (ANOVA) manifested significant variations for tested genotypes, locations, years, genotype × year, and genotype × location interactions revealing the influence of environmental factors on yield traits. All four environments showed discrimination power, whereas E2 and E3 were found as the representative environment as they fall near the Average-Environment axis (AEA). The AMMI biplot PC1 contributed 79.20% variability and PC2 contributed 15.18% variability. From the GGE biplot analysis, the rice lines Phouren, JBB-631-1, and JBB-1325 were found to be the best and most stable. The rice lines Phouren, PUP-229, and TI-112 were stable in the first sub-group Dhadesugur-Wet 2020 (E1). The rice lines Langphou, and NPK-45 were stable in the second sub-group ICAR-IIRR-Wet 2020 (E3). Environment ICAR-IIRR-Dry 2019 (E2) was the third subgroup and the rice lines Moirangphou-Yenthik and TI-3 topped for the same. The ICAR IIRR-Dry 2020 (E4) environment formed the fourth subgroup where Phouren-Amubi, TI-128 and JBB-1325 topped the season. In conclusion, this study revealed that G × E interactions are significant for yield variation, and its AMMI and biplots analysis are efficient tools for visualizing the response of genotypes to different locations.

Control of bancroftian filariasis by diethylcarbamazine medicated common salt in Karaikal, Pondicherry, India.

A trial of diethylcarbamazine (DEC) mixed in crystal common salt at a concentration of 0.15 to 0.2 per cent was carried out for 46 months (1982 to 1986) in Karaikal town and five commune panchayats of Pondicherry for control of bancroftian filariasis. Comparison of pre and post trial surveys showed 97.6 per cent reduction of microfilaria rate. No microfilaria or disease case was found in less than 5 years age group in the post trial survey. There was about 72 per cent reduction of disease rate. In the post trial substantial reduction of disease manifestation was found in 40 years and below age groups. Vector Culex quinquefasciatus density, filaria infection and infectivity rates were monitored only in Karaikal town. Infective vector mosquitoes were found in 1982 and 1983 only but afterwards no infective mosquito was encountered.

Susceptibility status of vectors of Japanese encephalitis to insecticides in south Arcot and Tirunelveli districts of Tamil Nadu.

Villages in South Arcot and Tirunelveli districts with high incidence of Japanese Encephalitis were selected for the study of insecticidal resistance to vectors. Culex vishnui and Anopheles hyrcanus group were found to be resistant to DDT (4 per cent for 60 min. exposure) and dieldrin (0.4 per cent for 60 min. exposure) but susceptible to Malathion (5 per cent for 60 min. exposure). So far, this is perhaps the first report of Anopheles hyrcanus group resistant to DDT and dieldrin to be reported from this area. The resistance may be due to extensive use of DDT and HCH for agricultural purposes.