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Khatri-Chhetri H.B.,District Agriculture Development Office | Khatri-Chhetri H.B.,Institute of Agriculture and Fisheries Research | Waeyenberge L.,Institute of Agriculture and Fisheries Research | Manandhar H.K.,Nepal Agricultural Research Council | And 2 more authors.
Journal of Invertebrate Pathology | Year: 2010

A survey of entomopathogenic nematodes (EPN) was conducted for the first time in Nepal during June-December 2007. EPN were recovered from 29 of the 276 soil samples (10.50%). Molecular and morphological tools were used to identify the isolates. Among 29 positive samples, seven samples (24.14%) yielded heterorhabditids (Heterorhabditis indica) and 22 samples (75.86%) contained steinernematids. Among steinernematids, seven isolates were identified as one of four described species (Steinernema abbasi, S. cholashanense, S. feltiae and S. siamkayai) whereas 15 isolates did not fit any description. H. indica was recovered from diverse habitats. Distribution of steinernematids has followed ecological niches and localized areas. © 2009 Elsevier Inc. All rights reserved.

Gaihre Y.K.,International Rice Research Institute | Gaihre Y.K.,University of the Philippines at Los Banos | Gaihre Y.K.,Nepal Agricultural Research Council | Gaihre Y.K.,International Fertilizer Development Center | And 3 more authors.
Plant and Soil | Year: 2013

Aims: Two pot experiments in a "walk-in" growth chamber with controlled day and night temperatures were conducted to investigate the influence of elevated temperatures along with rice straw incorporation on methane (CH4) and nitrous oxide (N2O) emissions as well as rice yield. Methods: Three temperature regimes-29/25, 32/25, and 35/30 °C (Exp. I) and 29/22, 32/25, and 35/28 °C (Exp. II), representing daily maxima/minima were used in the study. Two amounts of rice straw (0 and 6 t ha-1) were applied with four replications in each temperature regime. CH4 and N2O emissions as well as soil redox potential (Eh) were monitored weekly throughout the rice-growing period. Results: Elevated temperatures increased CH4 emission rates, with a more pronounced effect from flowering to maturity. The increase in emissions was further enhanced by incorporation of rice straw. A decrease in soil Eh to <-100 mV and CH4 emissions was observed early in rice straw-incorporated pots while the soil without straw did not reach negative Eh levels (Exp. I) or showed a delayed decrease (Exp. II). Moreover, soil with high organic C (Exp. II) had higher CH4 emissions. In contrast to CH4 emissions, N2O emissions were negligible during the rice-growing season. The global warming potential (GWP) was highest at high temperature with rice straw incorporation compared with low temperature without rice straw. On the other hand, the high temperature significantly increased spikelet sterility and reduced grain yield (p < 0.05). Conclusions: Elevated temperature increased GWP while decreased rice yield. This suggests that global warming may result in a double negative effect: higher emissions and lower yields. © 2013 Springer Science+Business Media Dordrecht.

He J.,China Agricultural University | Li H.,China Agricultural University | Rasaily R.G.,China Agricultural University | Rasaily R.G.,Nepal Agricultural Research Council | And 5 more authors.
Soil and Tillage Research | Year: 2011

Soil deterioration and the accompanying decline in crop yields are the main factors limiting the further development of agriculture in North China Plain. The long-term effects of no tillage (NT) and conventional tillage (CT) on soil properties and crop yields were investigated in annual double cropping system of winter wheat-summer maize in the Gaocheng in Hebei, North China Plain over a 11-year period (1998-2009). Long-term NT significantly (P< 0.05) increased soil organic matter, available N and P in the top 10. cm by 16.1%, 31.0% and 29.6% as compared to CT treatment. Mean percentage of macro-aggregates (>0.25. mm, +8.1%) and macroporosity (>60. μm, +43.3%) was also enhanced statistically (P< 0.05) in the 0-30. cm soil layer. Winter wheat and summer maize yields tended to be 3.5% and 1.4% higher under NT than under CT, particularly in the dry years, suggesting that the change in soil physical properties, soil fertility and moisture has provided a better environment for crop development. These improvements in soil properties and yields are of considerable importance for the degraded soils in semiarid North China Plain, as well as for food security, sustainable agriculture and carbon storage in the annual double cropping areas of China. © 2011 Elsevier B.V.

Upadhyay K.P.,Nepal Agricultural Research Council
Acta Horticulturae | Year: 2010

Cucumber production in winter in Nepal fetches off-season market. To select appropriate cultivar, local and exotic cultivars were evaluated in three-meter high plastic house (plastic quality 500 gauge) at Regional Agricultural Research Station (RARS), Lumle, Nepal (1,675 m.a.s.l.) from late winter to summer season in 2003, 2004 and 2005. Replicated experiment was conducted with seven cultivars in first year, selected six in second year and five in third year under a randomized complete block (RCB) design. Seedlings raised in polypots before one month of transplanting were transplanted at 1.5 m (row to row) × 1.5 m (plant to plant). Fertilizers were applied with 20 tons FYM and 60:30:25 N:P2O5:K2O kg/ha. Observations were recorded on yield related parameters. The overall results revealed that the 'Mahyco Green Long', an Indian cultivar was superior in all the years. The popular local cultivar 'Bhaktapur Local' was found at par with 'Mahyco Green Long'. This result gives new information on cultivars suitable for winter cucumber production which are superior to existing recommended cultivar 'Kusule' and other cultivars.

Jensen B.D.,Copenhagen University | Vicente J.G.,University of Warwick | Roberts S.J.,Nepal Agricultural Research Council | Manandhar H.K.,Plant Health Solutions
Plant Disease | Year: 2010

Black rot caused by Xanthomonas campestris pv. campestris was found in 28 sampled cabbage fields in five major cabbage-growing districts in Nepal in 2001 and in four cauliflower fields in two districts and a leaf mustard seed bed in 2003. Pathogenic X. campestris pv. campestris strains were obtained from 39 cabbage plants, 4 cauliflower plants, and 1 leaf mustard plant with typical lesions. Repetitive DNA polymerase chain reaction-based fingerprinting (rep-PCR) using repetitive extragenic palindromic, enterobacterial repetitive intergenic consensus, and BOX primers was used to assess the genetic diversity. Strains were also race typed using a differential series of Brassica spp. Cabbage strains belonged to five races (races 1, 4, 5, 6, and 7), with races 4, 1, and 6 the most common. All cauliflower strains were race 4 and the leaf mustard strain was race 6. A dendrogram derived from the combined rep-PCR profiles showed that the Nepalese X. campestris pv. campestris strains clustered separately from other Xanthomonas spp. and pathovars. Race 1 strains clustered together and strains of races 4, 5, and 6 were each split into at least two clusters. The presence of different races and the genetic variability of the pathogen should be considered when resistant cultivars are bred and introduced into regions in Nepal to control black rot of brassicas. © 2010 The American Phytopathological Society.

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