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101.
Dennis J. Tobias Robert W. Stack Krishna D. Puri Neil Riveland Shaobin Zhong 《Euphytica》2009,167(2):165-172
Common root rot (CRR), primarily caused by Cochliobolus sativus, is one of the important soil borne diseases of wheat (Triticum aestivum L). To gain information about resistance of hard red spring wheat (HRSW) to the disease, forty HRSW cultivars and advanced
breeding lines were grown and evaluated in a completely randomized block design for reaction to CRR from 2000 to 2002 in a
field plot with high natural inoculum of C. sativus at Williston, ND. Plant root samples during the soft to mid-dough stage were collected and CRR incidences and severities
were scored using the subcrown internode index method. Disease severities (DS) varied from 24–61% in 2000 and 2002, but were
relatively low in 2001 (19–40%). None of the wheat cultivars was immune to CRR. The genotypes Canon, Forge, Dandy, Ember,
Butte 86, Oxen, AC Barrie, Parshall, and 2371 had higher DS (>45%) and exhibited susceptible disease reactions. However, the
genotypes ND 722, AC Cadillac, HJ 98, Argent and Scholar had lower levels of DS throughout the study period, and these were
better than, or similar to Amidon, the resistant check. The HRSW cultivars with consistent resistance to CRR during the three
year evaluation could be valuable resistance sources for use in breeding programs. 相似文献
102.
A farmers’ participatory survey was carried out in the mid-hill and plain (Terai) regions of Nepal to assess the diversity,
consumers’ preference for fruit quality and potential for selection of elite pomelo clones. A wide variation of morphological
characters of tree, fruit, leaf and seed was identified from information gathered and from laboratory analysis. Multivariate
analysis of the data produced five discrete groups, which were represented by plants from different agro-ecological regions
and soil types. The groups differed significantly in yield efficiency, fruit shape and size, pulp, juice, total soluble solids
and acid content, seed number, leaf shape and size. Some fruit characters, such as yield, size and acid content were found
to be affected by environment and genotype, whereas others, such as fruit shape, pulp colour, seed number, bitterness were
not affected by environment. Leaf shape and petiole wing shape were also not affected by the environment. Farmers were more
interested in quality characteristics rather than to aspects of yield. Six superior types were identified. 相似文献
103.
Anthony Imoudu Oyeogbe Tapas Kumar Das Kali Kinkar Bandyopadhyay 《Archives of Agronomy and Soil Science》2018,64(12):1635-1645
Conservation agriculture (CA) practice increases agronomic productivity and soil fertility, yet CA stimulate nitrogen (N) immobilization and weed interference during the early periods of implementation. This study focuses on efficient N management by soil testing and optical sensor (GreenSeekerTM) information; and weed management using brown manuring (Sesbania aculeata co-culture) and herbicide mixtures under CA-based maize (Zea mays L.) – wheat (Triticum aestivum L. emend Fiori & Paol) system in the Indo-Gangetic Plains. Fertilizer N application guided by the optical sensor increased grain yields of maize and wheat up to 20 and 14% (average of two years), respectively, compared to whole N application at sowing. Weed management using brown manuring in maize and herbicide mixtures in wheat increased the grain yields up to 10 and 21%, respectively, over the weedy check. The optical sensor-based N management saved up to 45 and 30 kg N ha–1 of the optimized N fertilizer rate in maize and wheat, respectively, over whole N application. Fertilizer N management coupled with brown manuring resulted in 5 and 4% higher soil organic carbon accumulation. Implementing efficient N fertilizer and weed management in the early years of CA can improve agronomic yield, fertilizer savings, and soil organic carbon content. 相似文献
104.
Isha Das Sugata Hazra Sourav Das Sandip Giri Abhra Chanda Sourav Maity Shubhadeep Ghosh 《Fisheries Science》2018,84(6):995-1008
An ecosystem model was constructed for the northern Bay of Bengal (nBoB) using Ecopath (version 6.4.4). The model covered an area of 18,500 km2. There were 32 functional groups in the model including the non-living group, detritus. Trophic levels (TLs) for individual groups ranged from 1.0 to 4.22. Ecotrophic efficiency for most of the small pelagic fishes was found to be greater than 0.7. For hilsa it was 0.853, indicating high exploitation of this fish within the system. The nBoB was estimated to be a low ascendancy area (~?19.2%) with a system overhead of 80.8%, which indicates system stability and a certain maturity. The total system throughput and the total primary production/total respiration estimated for the study area indicate that nBoB is a maturing ecosystem. The mean TL of the catch for the study area was 3.115. The results indicate that the nBoB system is still in a developing stage. The low mean TL of the catch indicates fishing practices targeting fish of lower TLs in the system. In the long run, this may cause fishing down the food web, which will eventually lead to declining catches. These results indicate that present fishing practices are unsustainable for the nBoB ecosystem. 相似文献
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107.
Sen Chauhan Indra Gupta Ashok K. Khate Keviletsu Chauhan Anuj Krishna Shankar Rao Thakur Pathak Shivendra Hazra Ritwik Singh Maneesh 《Tropical animal health and production》2010,42(8):1809-1815
The objective of the study was to evaluate the effects of genetic and non-genetic factors on production of breeding bulls
and semen quality parameters in Karan Fries crossbred male by fitting least squares analysis. Genetically, the animals were
divided into three subclasses. The non-genetic factors were season of birth, period of birth, and age group with three subclasses
each for season of birth and period of birth. Age group was classified into four subclasses. The traits generated in the study
were number of males reaching semen donation stage (AFSC) and first freezing (AFSF), age at last semen collection (ALSC) and
last freezing (ALSF), age at disposal (AD), and lifetime semen production traits (up to 1 year after first freezing). The
effect of period of birth was significant for AFSC, AFSF, ALSC, and AD. It was also significant for total ejaculates produced
in a year. The age group had significant effect on AFSF. Effect of genetic group was significant for freezable ejaculates
produced in a year, for frozen semen doses produced in a year, and for number of ejaculates cryoprocessed in a year. Season
had no statistically significant effect on any of the traits studied. The influence of period revealed that the most of the
traits of breeding bulls improved after intermediate period, which could be due to better care, training, feeding, and other
management practices in the latter years. However, no consistent trend could be established for the effects of genetic groups
and other non-genetic causes on the traits considered. 相似文献
108.
Pyramiding Ty‐2 and Ty‐3 genes for resistance to monopartite and bipartite tomato leaf curl viruses of India 下载免费PDF全文
H. C. Prasanna D. P. Sinha G. K. Rai R. Krishna S. P. Kashyap N. K. Singh M. Singh V. G. Malathi 《Plant pathology》2015,64(2):256-264
Breeding resistance to whitefly‐transmitted begomoviruses is an important goal of tomato breeding programmes worldwide. So far, resistance to begomoviruses in tomato has been achieved using wild species, and at least five resistance genes (Ty genes) have been studied. The present study was undertaken to combine Ty‐2 and Ty‐3 and to determine the effect of pyramiding on infection of tomato by three diverse begomovirus species. The diagnostic ability of the markers linked to Ty genes was assessed and marker‐assisted selection was used to develop pyramided tomato lines from the crosses between Ty stocks. Five stable pyramided tomato lines that differ in fruit morphology and yield potential were developed. The horticultural performance of pyramided lines in field trials showed that the yield and horticultural traits are well maintained in the plants. The response of these lines was assessed using agroinoculation and field tests in a disease hotspot. The pyramided lines and Ty‐3‐carrying lines exhibited a high level of resistance to the monopartite and two bipartite begomoviruses tested. The pyramided tomato lines developed in this study could be important genetic resources for sustainable tomato production in areas affected by tomato leaf curl virus disease. The combined results of disease resistance tests also showed that Ty‐3 is critical for achieving broad‐spectrum resistance. The limitations of relying on a single gene and the importance of pyramiding are discussed in the light of available evidence on frequent recombination in begomoviruses. 相似文献
109.
110.
Joseph?G.?SchnitzlerEmail author Peter?H.?M.?Klaren Emeline?Mariavelle Krishna?Das 《Fish physiology and biochemistry》2016,42(2):607-616
The sheepshead minnow is widely used in ecotoxicological studies that only recently have begun to focus on disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However, reference levels of the thyroid prohormone thyroxine (T4) and biologically active hormone 3,5,3′-triiodothyronine (T3) and their developmental patterns are unknown. This study set out to describe the ontogeny and morphology of the thyroid gland in sheepshead minnow, and to correlate these with whole-body concentrations of thyroid hormones during early development and metamorphosis. Eggs were collected by natural spawning in our laboratory. T4 and T3 were extracted from embryos, larvae and juveniles and an enzyme-linked immunoassay was used to measure whole-body hormone levels. Length and body mass, hatching success, gross morphology, thyroid hormone levels and histology were measured. The onset of metamorphosis at 12-day post-hatching coincided with surges in whole-body T4 and T3 concentrations. Thyroid follicles were first observed in pre-metamorphic larvae at hatching and were detected exclusively in the subpharyngeal region, surrounding the ventral aorta. Follicle size and thyrocyte epithelial cell heights varied during development, indicating fluctuations in thyroid hormone synthesis activity. The increase in the whole-body T3/T4 ratio was indicative of an increase in outer ring deiodination activity. This study establishes a baseline for thyroid hormones in sheepshead minnows, which will be useful for the understanding of thyroid hormone functions and in future studies of thyroid toxicants in this species. 相似文献