Correlation of Weather Variables on Emergence of a Virus Disease Bud Necrosis Disease of Greengram Incited by Soybean Yellow Mottle Mosaic Virus at Raichur, Karnataka

Greengram [(Vigna radiata (L.) Wilczek] is the important pulse crop after chickpea and pigeonpea cultivated in India which is called as “Queen of pulses”, the crop is proned to be infected by many fungal and bacterial diseases. In recent years emergence of a virus disease bud necrosis of greengram was noticed in Raichur and the incidence of disease gradually increased in greengram growing areas of Karnataka. Incidence of bud necrosis disease of greengram and correlation with weather factors was studied during Kharif 2021 at research plot and MARS, UAS, Raichur, Karnataka. The study reveals that, on all four dates of sowing (25th June, 1st July, 9th July and 23rd July 2021), disease was initiated at 25 DAS and highest disease incidence was observed at 75 DAS. The peak activity of thrips was noticed during August month. The weather variables viz., maximum temperature was more than 32 °C, minimum temperature was more than 22°C, rainfall was less than 19 mm/day, morning relative humidity was less than 91 per cent, evening relative humidity more than 44 per cent, evaporation 4.3 mm/day and sunshine hours less than 6 hr/day was favorable for bud necrosis disease in four dates of sowing. Whereas, morning relative humidity, evening relative humidity and age of the crops were having positive relationship with progress of bud necrosis on all four dates of sowing. Thrips and rainfall showed a positive correlation with disease incidence in all dates of sowing except the fourth date of sowing.

Genetic Spectrum of Variation and Diversity for Yield and Yield Attributing Traits in Mutagenized Population of Sorghum (Sorghum bicolor L. Moench)

The present study was carried out in Agricultural Research Station, Hagari during rabi 2020, it was undertaken to assess nature of genetic variability and diversity among 200 mutant lines of M4 generation. The study revealed wide variation for yield and yield attributing traits, moderate GCV and PCV coupled with high heritability and genetic advance was observed for stem girth, panicle length and panicle width. The traits viz., stem girth, panicle length, panicle weight, panicle width, 100-seed weight, grain yield per plant and fodder yield showed high heritability and genetic advance as per cent of mean. A wider genetic diversity was observed for the different traits studied among the mutant lines as evidenced by the formation of thirteen clusters for the 200 mutant lines. Out of thirteen characters studied, fodder yield contributed majorly towards divergence with value of 37.35 per cent followed by 100-seed weight contributes (20%), grain yield contributes (15%) and other traits contribute minorly for divergence.

Bio-efficacy of newer insecticides against tomato leaf curl virus disease and its vector whitefly (bemisia tabaci) in tomato.

Tomato leaf curl begomovirus and its vector whitaefly (Bemisia tabaci) are the major limiting factors, which cause substantial yield loss in tomato. Present investigations on Invitro efficacy of new insecticide molecules on whitefly mortality and leaf curl virus transmission revealed that adult mortality varies with the length of incubation period of different insecticides, as increase in the concentration of insecticides, adult mortality was more in the initial hrs of incubation. Among the test chemicals, cyantraniliprole 10 OD at 60 and 75 g.a.i/ha have knockdown effect and caused 100 per cent mortality at 48 hrs after treatments and also recorded least virus transmission (10 and 5 % respectively). Whiteflies remained active and caused 100 per cent transmission of leaf curl virus in the untreated check. The incidence of B. tabaci and tomato leaf curl virus disease (disease inoculums) was stastically varied with respect to different dose of insecticides evaluated at two different levels of observation. Among the different concentrations of new molecule cyantraniliprole (Cyazypyr 10 OD) (45, 60 and 75 g.a.i/ha) tested, cyantraniliprole 10 OD at 60 and 75 g.a.i/ha. were found more effect in reducing both whitefly and disease incidence at first and final observation with the least whitefly population and leaf curl disease incidence. Correspondingly the yields were high in plot received cyantraniliprole 10 OD 75 g.a.i/ha (32.5tons/ha) and significantly superior over the standard check triazophos (23.5tons/ha.) followed by cyantraniliprole 10 OD at 60 g.a.i/ha (29.2 tons/ha) and cyantraniliprole 10 OD at 45 g.a.i/ha (27.4 tons/ha).