Berner D.,U.S. Department of Agriculture |
Smallwood E.,U.S. Department of Agriculture |
Cavin C.,U.S. Department of Agriculture |
Lagopodi A.,Aristotle University of Thessaloniki |
And 6 more authors.
Biological Control | Year: 2013
Canada thistle (Cirsium arvense, CT) is one of the worst weeds in temperate areas of the world. The rust fungus Puccinia punctiformis was first proposed as a biological control agent for CT in 1893. The rust causes systemic disease, is specific to CT, and is in all countries where CT is found. Despite a 120-year lapse since biological control with the rust was proposed, establishment of epiphytotics of the rust have previously been unsuccessful due to incomplete understanding of the disease cycle. In this study, newly-emerging rosettes in the fall are proposed as the physical and temporal infection courts for basidiospores, from germinating teliospores, to systemically infect CT and give rise to systemically diseased shoots the following spring. To test this hypothesis, rosettes of CT were inoculated in the fall with either telia-bearing leaves collected in mid-summer or with greenhouse-produced teliospores. Field sites were located near Kozani, Greece, Moscow, Russia, Christchurch, New Zealand, and Ft. Detrick, Maryland, USA. Telia-bearing leaves, which were used as inoculum in 12 of 13 field sites, were collected near each field site from CT shoots in close proximity to systemically diseased CT shoots producing aeciospores in the spring. Aeciospore infections of the leaves of these nearby shoots gave rise to uredinia which turned to telia in mid- to late-summer. Temperature and dew conditions at inoculation in the fall at each site were very favorable for teliospore germination. Rosettes inoculated in the fall were marked with flags, and systemically diseased shoots emerging near these flags the following spring were recorded. In 11 of the sites in these countries, individual rosettes were inoculated 2, 4, 6, or 8 times with telia-bearing leaves. Proportions of rosettes giving rise to systemically diseased shoots, out of the number of rosettes inoculated, were analyzed. Inoculations in all 13 sites produced systemically diseased shoots. A separate study on the phenology of CT showed that the maximum rate of leaf abscission occurred at the time of maximum emergence of new CT rosettes in the fall. This period coincided with an annually occurring period of sustained dew and favorable temperatures for teliospore germination. In nature, abscising telia-bearing leaves likely come into contact with a receptive rosette during favorable conditions for teliospore germination in the fall. This study demonstrates that epiphytotics of systemic rust disease of CT can be routinely established, by mimicking the natural disease cycle. © 2013.
Goncharova Y.K.,All Russia Rice Research Institute
Russian Journal of Genetics | Year: 2013
The nature of heterosis is discussed and selective elimination of alleles (introduced in the hybrid genotype by the parental forms) in anther culture is shown. This supports the possibility of removing viability-reducing alleles (lethal, semilethal, and less effective alleles) from the genotypes of heterotic hybrids in anther culture. © 2013 Pleiades Publishing, Ltd.
Goncharova J.K.,All Russia Rice Research Institute |
Kharitonov E.M.,All Russia Rice Research Institute
Russian Journal of Genetics: Applied Research | Year: 2016
The objectives of the current study were to identify the genetic material, which is characterized by a high growth rate and maximum root system size; to study the variability of Russian and foreign rice varieties for the markers associated with the genes, which determine efficient phosphorus utilization; to assess the possibility of using the simple sequence repeat (SSR) markers discussed in the current work for the introgression of the previously mapped genes; and to subdivide the donor samples identified in the Russian gene pool into groups characterized by a high probability of resistance development via different genetic mechanisms. The features which determine the intensity of the phosphorus uptake and their inheritance in rice varieties are discussed. We have studied the variability of the 72 rice varieties of Russian and foreign origin for the development rate of the root system and its size at maturity. The highest development rate of the root system was observed for the following varieties: Liman, Arborio, Dalnevostochnyi, Selenio, Oceano, Atlant, Musa, Fontan, Cerere, Sharm, Serpentine, Khankaiskii 52, Leader, Boyarin, and Druzhnyi. The samples of Russian origin were characterized by a higher growth rate than the Italian ones. The root weight at the stage of maturation varied from 1.5 to 4.5 g in different rice varieties, the maximum root weight being observed in the following varieties: Carnise, Rapan, Onix, and G-57. The root length varied from 17 to 26 cm with the highest length being displayed by the D 25-2, G 75-5, Ryzhik, G-52, Krepysh, and Snezhinka varieties. The variability observed in the Russian and foreign varieties for all the examined SSR loci associated with the genes controlling the phosphorus uptake showed that marker assistant selection may be carried out for this feature in the gene pool under study. The maximum allele number was detected for the RM 247 marker, localized on chromosome 12. © 2016, Pleiades Publishing, Ltd.
Dubina E.V.,All Russia Rice Research Institute |
Mukhina Z.M.,All Russia Rice Research Institute |
Kharitonov E.M.,All Russia Rice Research Institute |
Shilovskiy V.N.,All Russia Rice Research Institute |
And 5 more authors.
Russian Journal of Genetics | Year: 2015
Based on modern technologies of molecular DNA-markers, blast disease–resistance genes (Pi-ta, Pi-b, Pi-1, Pi-2, and Pi-33) were introgressed and pyramided into domestic rice varieties to give them longterm disease resistance. For that purpose, this case study uses SSR-markers closely linked to these genes, as well as intragenic markers of genes Pi-ta and Pi-b. Multiplex PCR systems were created for simultaneous identification of two resistance genes in the hybrid progeny for the following combinations: Pi-1 + Pi-2, Pi-ta + Pi-b, Pi-ta + Pi-33. © 2015, Pleiades Publishing, Inc.