جستجوی مقالات مرتبط با کلیدواژه "رقم مقاوم" در نشریات گروه "زراعت"

Sugar beet is one of the root knot nematode (Meloidogyne spp.) hosts and destructive virus (Beet necrotic yellow vein virus, BNYVV) which is the cause of rhizomania disease. The use of resistant cultivars is the simplest and most efficient method of managing plant diseases. Based on this, to develop a cultivar resistant to rhizomania and root knot nematode in sugar beet, two populations carrying resistance genes to the above-mentioned diseases were identified and selected. From the target population, 10 half-sib families were developed and crossed with single cross monogerm 7112*SB36 and 10 monogerm hybrids were developed. Evaluation of hybrids in terms of quantitative and qualitative traits led to the selection of four superior hybrids including SBSI043, SBSI042, SBSI041 and SBSI044. Results of combined analysis of these hybrids with a domestic resistant control to rhizomania (Arya) and two foreign resistant controls (Castile and Rosier) and a susceptible cultivar for two years in a field infected to rhizomania in four regions (Mashhad, Shiraz, Hamadan and Qazvin) showed the complete superiority of all four hybrids compared with domestic resistant control. This hybrid was recognized as the best domestic hybrid in the test to determine the agricultural capacity of new domestic cultivars in seven infected and non-infected regions of the country, with an average sugar yield of 8.79 tons per hectare after two foreign controls. The new hybrid SBSI043 is the first cultivar with double-resistant (rhizomania and root knot nematode) named "Asia" and was introduced to growers for spring cultivation in different regions of my country, especially the regions infected to both diseases and exports to Azerbaijan, Syria and Egypt countries.

In order to study the effects of nitrogen and phosphorus biofertilizers on photosynthetic pigments, grain yield, yield components and grain protein content of two pea (Pisum sativum L.) varieties under different irrigation regimes; a split-split plot experiment was conducted based on a randomized complete block design with three replications at a field in Farsan, southwestern Iran, in 2021. The main plots were allocated to irrigation treatments including: irrigation after 50, 75 and 100 mm (I1, I2 and I3, respectively) cumulative evaporation from class A evaporation pan and the sub plots were allocated to different sources of biofertilizers treatments including: control (no biofertilizer application), Azotobarvar-1(nitrogen), Phosphatebarvar-2 (phosphorus) and Azotobarvar-1 + Phosphatebarvar-2 (nitrogen + phosphorus). Sub-sub plots were allocated to two varieties of peas (Majarestani and Wolfholland). Results showed that in Majarestani variety mild drought stress increased chlorophyll a and b contents, but severe drought stress decreased them. In Wolfholland variety, both mild and severe drought stress decreased chlorophyll a and b contents. In both varieties, mild drought stress increased carotenoid contents, but severe drought stress decreased them. Biofertilizers were effective in improving chlorophyll a, b and carotenoid contents, particularly under drought stress conditions. The drought stress reduced the grain yield and yield components of both pea varieties but application of biofertilizers moderated the effects of drought stress. The highest value of grain yield was obtained from the Majarestani variety when grown under full irrigation conditions (I1) and nitrogen biofertilizer application. Under the mild and severe drought stress (I2 and I3), the highest value of grain yield was obtained from Majarestani variety in the presence of phosphorus and nitrogen + phosphorus biofertilizer application, respectively. Majarestani variety outranked the Wolfholland in terms of  pods/plant, grain/pod and grain yield under both stress and normal conditions, but the latter variety indicated a greater 1000-grain weight. Therefore, Majarestani variety is a more suitable cultivar, particularly under drought stress conditions. Grain protein percentage was not affected by variety. The highest percentage of grain protein content was achieved with I2 irrigation and nitrogen + phosphorus biofertilizer treatments, averaged over the examined varieties. To conclude, given the prevalence of water scarcity in the semi-arid regions of Iran’s type, further examinations of more drought resistant varieties such as Majarestani and application of biofertilizers may prove suitable for reducing the adverse effects of drought stress.

This study was performed to screen 35 commercial potato cultivars and 24 promising clones for resistance to Potato virus X (PVX) using biological and molecular marker assays. To purify and propagate the virus, infected potato samples were inoculated on common globe amaranth (Gompherena globose) and then on tobacco and maintained under in vitro conditions. The reaction of genotypes to PVX were evaluated based on International Potato Centre (CIP) standard method by mechanical inoculation and grafting under the greenhouse conditions. In mechanical experiment, three plants of each genotype were inoculated and the resistant genotypes were identified based on virus detection by ELISA. To determine the type of resistance, the resistant genotypes were grafted on tomato cv. Rutgers plants infected with PVX in three replications, and their infection by virus was examined using DAS-ELISA, 21 days post inoculation. The results of both experiments showed that 12 commercial potato cultivars and 11 promising clones were extremely resistance (ER) to PVX. Moreover, nine commercial potato cultivars and one promising clone showed hypersensitive resistance (HR) reaction. Twenty-six genotypes showed infection to PVX, at least in one replication, and considered as susceptible to the virus. In addition, resistance genes, Rx1 and Rx2, were successfully amplified in resistant genotypes using specific primers 5RX1 and 106RX2, respectively. However, no PCR product could be detected in the PVX susceptible and HR genotypes which were in accordance with the results of biological assays. Finally, Rx1 and Rx2 genes were detected in 13 and seven potato genotypes, respectively. It was concluded that genotypes carrying Rx1 and Rx2 genes can be used in potato breeding programs to develop new potato cultivars with desirable agronomic characteristics and resistance to PVX.