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Investigations were conducted to evaluate three Metarhizium anisopliae strains (two local isolates: Ma-L-1 and Ma-L-2; and one commercial strain: Ma-F-1) to demonstrate affects on growth parameters and pathogenicity against third instars of Spodoptera litura. A study of dose mortality response showed that the strain Ma-L-1 was highly virulent with an LC50 of 16.523× 105conidia/ml. Time mortality response of the three strains revealed that as the concentrations increased the LT50 values decreased. The strain Ma-L-1 was most effective followed by Ma-F-1 and Ma-L-2 strains of M. anisopliae. Laboratory experiment indicated that cumulative mortality of larvae increased with increase in concentration and exposure period. Younger larvae were highly susceptible to the treatment than older ones. Among the three test strains of M. anisopliae, the strain Ma-L-1 was found superior over others due to its quick growth, high sporulation ability and highest virulence against the candidate larvae. Source

Durga K.K.,Seed Research and Technology Center
Journal of Arid Land

Horsegram is an important and unexploited tropic and sub-tropic legume crop grown mostly in dry land agriculture. The study involving 23 cultivars of horsegram (Dolichos uniflorus) was conducted at the Seed Research & Technology Centre in Rajendranagar, Hyderabad, India during the early spring seasons of 2008 and 2009 to assess the nature and magnitude of variability in the existing species and also to identify diverse parents for use in further breeding programmes. The results indicated significant differences among the 23 cultivars for all characters studied, indicating the presence of sufficient genetic variation. High variability and heritability coupled with high genetic advance were reported for seed yield per plant and pod hulm per plant, indicating additive gene action and a possible scope for the improvement of these characters. Mahalanobis D2 statistics grouped all the 23 cultivars of horsegram into six clusters. The maximum inter cluster distance (62.39) was noticed between cluster IV (HG 50) and cluster V (HG 11). The maximum intra cluster distance ranged from 0 (clusters III, IV, V and VI) to 15.17 (cluster I), indicating that the genotypes in these clusters were relatively more diverse than the genotypes within other clusters. Seed yield per plant contributed the maximum (33.20%) to the genetic divergence. Source

Anitha G.,AICRP on Biological Control | Parimala K.,Seed Research and Technology Center
Ecology, Environment and Conservation

The pod bug, Clavigralla scutellaris Spinola in pigeonpea is an important pest in the semi-arid areas of Andhra Pradesh viz, Mahaboobnagar and Ranga Reddy districts and causes around 15% yield losses. A Platygastrid, Gryon clavigrallae Mineo parasitizes eggs of the bug effectively and hence its conservation is important while formulating the management tactics. Since information about the parasitization efficacy and its dynamics is scant, a study was carried out during rabi seasons of 2010-11 and 2011-12 to observe the extent of its parasitization and its fluctuations as affected by abiotic and biotic factors. Results revealed that parasitization started from the first fortnight of December and reached a peak in the second fortnight of January. It was found to be in the range of 11.3-89.5 % in 2010-11 and 10.9-88.9% in 2011-12. Correlation and regression studies suggested that mean temperature had a substantial negative effect (r=-0.51) on parasitization, while sunshine hours and host density had a significant positive relationship (r=0.82 and 0.80 respectively). Mean relative humidity, rainfall and wind speed did not influence parasitization. Coefficient of determination (r2) was high (0.93) indicating the prominence of abiotic and biotic factors on parasitization by G.clavigrllae. A multiple regression equation was fitted and discussed. © EM International. Source

Anitha G.,All India Coordinated Research Project on Biological Control | Parimala K.,Seed Research and Technology Center
Plant Archives

Biointensive IPM incorporates ecological and economic factors into agricultural system design and decision making and addresses public concerns about environmental quality and food safety. Its benefits include reduced chemical input costs, reduced on-farm and off-farm environmental impacts and more effective and sustainable pest management (Dufour, 2001). A field study was undertaken in kharif seasons of 2009-10 and 2010-11 in A.R.I. Farm, Rajendranagar, Hyderabad (A.P.), India to know the comparative reaction of four rice varieties viz., to stem borer infestation when cultivated under BIPM and farmers' practices. Analysis of two-year results showed that BIPM treated plots recorded significantly lesser dead hearts and white ears in all the four varieties compared to the plots grown using farmers' practices. Among the different varieties in BIPM and Farmers' module, there was no significant difference among the different varieties with respect to dead hearts, white ears and yield. Study of the extent of parasitisation of stem borer egg masses collected from the fields revealed that higher number (88.6%) of completely parasitized egg masses were recorded in BIPM plots compared to FP plots (55.45%). Tetrastichus, Telenomus and Trichogramma were found to be the dominating species. Tetrastichus was the single dominant species in 89.1% of the completely parasitized egg masses, Telenomus to an extent of 7.2% and Trichogramma upto 3.7%. Source

Parimala K.,Seed Research and Technology Center | Anitha G.,AICRP on Biological Control | Reddy A.V.,Seed Research and Technology Center
Plant Archives

Chickpea (Cicer arietinum L.) is one of the important pulse crops in rainfed areas of Andhra Pradesh, India. The crop requires higher levels of nitrogen and phosphorus and is often susceptible to deficiencies of iron, sulphur and zinc. A field experiment was conducted at Seed Research and Technology Centre, Rajendranagar, Hyderabad (A.P.), India to study the effect of macro and micronutrients on yield and seedling quality parameters of chickpea variety JG-11. Foliar applications of DAP (2%), Urea (2%), Zn (0.5%), FeSO 4 (0.5%), KCl (1%) and KNO3 (1%) were done twice at pre-flowering and flowering stage. DAP (2%) and Urea (2%) sprays recorded maximum number of branches per plant which suggests that overall biomass could be increased by these sprays. Zn (0.5%) enhanced the number of pods/plant and led to maximum seed yield/plant compared to all other treatments. Application of zinc enhanced the root growth, nodulation and nitrogen content of nodules indirectly contributing to the increased yield. KCl (1%) sprays had a positive effect on root and shoot growth recording maximum seedling root length, shoot length, fresh weight, dry weight and vigour index. Regression studies between number of pods/ plant and seed yield/plant showed that unit increase in number of pods/plant resulted in an increase of 1.83g of seed yield/ plant. Source

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