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51.
Scanga JA Hoffman T Picanso J Rajopadhye SV Kim DG Gupta A Forbes R Ladd J Burns PJ 《Journal of animal science》2007,85(2):503-511
Many of the efforts surrounding the development of the National Animal Identification System have encompassed the identification of livestock production and handling premises as well as individuals or herds of animals, whereas little effort has been directed toward the ultimate goal of animal traceback within 48 h. A mock data set representative of the Colorado cattle population was created for modeling of cattle traceability. Using this data set, algorithms were developed to complete rapid and accurate traceback and traceforward of animals or premises or both. On July 19, 2005, the Colorado Department of Public Health and Environment, in conjunction with the Colorado Department of Agriculture, conducted a test exercise pertaining to homeland security. The exercise team randomly identified animal number 926,583 (of the 2 million total animals) as a potentially infected animal of interest and requested a traceback of this animal. Traceback was accomplished in 215 s, and 540 primary coresident animals were identified. However, due to animal movements, the number of coresidents (animals exposed, directly or indirectly, to the animal of interest) expanded with coresidency level (level 1 = direct contact; level 2 = direct contact with an animal that had direct contact with the animal of interest; level 3 = direct contact with an animal that had contact with an animal that had direct contact with the animal of interest, etc.) to more than 1.2 million coresidents at level 4, and more than 90% of all animals identified as a coresident at some level. In addition to the coresidency results, the premises containing the coresidents were identified and sorted by the number of coresidents. Because of animal movement, all 19,391 premises included in the data set had coresidents at some level. This exercise demonstrated the capability of the developed algorithms to complete rapid traceback and the complexity of the resulting animal traceback output. 相似文献
52.
The genotypes of Avena sativa were crossed to A. magna Murph. et Terrell, from the sterile pentapliod F1 amphiploids were successfully developed after colchicine treatment. The C1 plants were observed for their morphology, cytology and fertility. These plants were characterized by longer and broader glumes, swollen pedicel attachment, pubescent lemmas, bold seeds and persistent spikelets. Other characters, viz., final plant height, rachis length, peduncle length and spikelets per panicle were intermediate. All plants hail the chromosome number 2n = 70 or close to. 7C. Due to stickiness of chromosomes, meiosis of only two decaploid plants could be studied in detail. The average chromosome Association was 1.3 I + 28.56 II + 1.4 III + 1.77 IV + 0.07 VI and 0.13 I + 28.7 II + 0.14 III + 2.09 IV + 0.59 VI; but in some cells up to 35 bivalents were observed. Seed set as well as pollen fertility and size exhibited great variation. 相似文献
53.
In a backcrossing programme to transfer desirable characters from wild Avena maroccana Gdgr. to cultivated oats, A. sativa L., meiotically stable plants in BC1F3 and BC2F2 progenies were isolated. The recovery of stable genotypes with 2n = 6×= 42 chromosomes indicated that two backcrosses are enough for such a programme. The cytological observations in various backcross generations are presented and discussed. 相似文献
54.
The cytological status of plantlets regenerated from shoot apical meristems of Pisum sativum was investigated. Chromosome counts in root apices of in vitro regenerated plants showed a preponderance of diploid cells. Moreover, the karyotypes of root-tips from plants derived from culture and from normal plants were basically the same. Topics such as the treatment of chromosomal armlength data, simple statistical comparison of samples derived from normal and regenerated plants are discussed. 相似文献
55.
Anthers of Brassica nigra, excised from fresh as well as cold-pretreated (3 days at 3 ± 2°C) buds cultivated on modified B5 medium (Gamborg et al. 1968) containing sucrose level varying from 2 % to 10 %, along with 1O?6M BAP (benzylaminopurine) and 9 × 10?6M 2,4-D (2,4-dichlorophenoxyacetic acid), developed calli and/or embryos. The latter response was observed only in anthers reared on media containing 6 % or higher levels of sucrose. On media containing two or four per cent sucrose, the anthers produced calli, exclusively. The growth of embryos was inhibited or else they started callusing if left on the media containing higher levels of sucrose. However, on transfer to MS medium (Murashige and Skoog 1962), containing 2 % sucrose, embryos started callusing and subsequently a few secondary embryos differentiated. Such embryos were sub-cultured on MS + 5 × 10?6M BAP + 2 % sucrose, wherein numerous shoots developed from embryos. The shoots were rooted by transferring to a medium containing 5 × 10?6M NAA (naphthalene acetic acid). Within two months of culture, some of these plants started flowering in vitro. 相似文献
56.
Summary Metroglyph and index score analysis was carried out with 15 Indian and 15 exotic varieties of maize currently being used in the breeding programme of the Coordinated Maize Improvement Project at the Indian Agricultural Research Institute. It was found that the Indian varieties under study fall into three morphological complexes which differed among themselves. The variability pattern of the second and third Indian complexes resembled that of Mexican and Colombian germ plasm. The variability pattern of the Caribbean germ plasm was different from the Indian complexes. Index score analysis also gave similar results. Previous breeding experiments also confirmed the findings that these varieties might have originated from a few Mexican or Colombian introductions. 相似文献
57.
58.
Wild Lens species/subspecies are a potential source for increasing genetic diversity in cultivated lentil. Four intraspecific crosses were attempted between cultivated and wild lentils. Viable hybrids were produced between L. culinaris ssp. culinaris × L. culinaris ssp. orientalis and L. culinaris ssp. culinaris × L. culinaris ssp. odomensis. Normal meiosis and pollen fertility were observed in the first set of crosses, whereas chromosomal abnormalities and reduced pollen fertility were observed in the second set of crosses. These crosses were also studied for some quantitative traits. The range, mean and coefficient of variation were calculated in parents, F1, F2 and BC1 generations to determine the extent of variability generated in the cultivated lentil through introgression of genes from wild lentil. The cultivated lentil × L. culinaris ssp. orientalis crosses showed substantially higher variability for all the traits than crosses involving cultivated lentil ×L. culinaris ssp. odomensis. The results of the present study indicated that these wild subspecies can be exploited for breeding purposes and their variation can easily be utilized to widen the genetic base of the cultivated lentil. 相似文献
59.
The genetics of resistance to three Indian pathotypes of Xanthomonas campestris pv. oryzae, namely, IX01, IX08 and IX09, was studied in a landrace of Indica rice ‘ARC 10464’. Resistance to each of the two pathotypes IX01 and IX09 was governed by two independently-inherited dominant genes while a single dominant gene was operative against patho-type 1X08. The joint segregation tests conducted on F2 plant progenies (F3 families) using pathotypes IX01, IX08 and IX09 suggested that the gene/(s) effective against each of the pathotypes are different. 相似文献
60.
R.G. Saini M. Kaur B. Singh Shiwani Sharma G.S. Nanda S.K. Nayar A.K. Gupta S. Nagarajan 《Euphytica》2002,124(3):365-370
The genetic bases of leaf rust resistance in wheat (Triticum aestivum L.) line CSP44, selected from the Australian cultivar Condor, and Indian cultivar VL404, were studied. The reaction patterns
of CSP44 and VL404 against Indian races 12, 77, 77-1, 77-2, 77-3, 77-4, 77-5 and 108 were different from reaction patterns
shown by near-isogenic lines with known adult plant resistance (APR) genes, viz. Lr12, Lr13, Lr22b and Lr34. Although the reaction patterns of CSP44 and VL404 were similar to the near-isogenic line Tc+Lr22a, tests of allelism indicated absence of Lr22a in both CSP44 and VL404. On the basis of genetic studies, their resistances in field tests against race 77-5, the most virulent
race from the Indian sub-continent, were each ascribed to two genes. One of the two genes in each wheat was identified to
be the non-hypersensitive APR gene Lr34. The second APR genes in CSP44 and VL404 gave hypersensitive reaction types and were recessive and dominant, respectively.
The gene in CSP44 was designated Lr48and the gene in VL404, Lr49.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献