Volume 44, Issue 75

Shuttle breeding is a breeding system where generations undergo sequential evaluations at different locations, developed by N. Borlaug. Our study aims to demonstrate an opportunity of application shuttle breeding method in sunflower lines development and also to show its advantages and disadvantages. Experiments were mainly conducted at the Central Station (Krasnodar) of All-Russia Research Institute of Oil Crops (VNIIMK). Krasnodar region is situated in the Southern part of Russia near the Black Sea. Part of our work was made at Seed and Plant Improvement Institute (Karaj, Iran) and Experimental Station near Borozdjan (Busher Province of Iran). Released and experimental sunflower hybrids and lines of VNIIMK breeding were used as a material. The experimental design was randomized blocks with three replications. Each replication had four rows and two central rows were analyzed only to exclude the border effect. It is shown that the application of the shuttle breeding technique to sunflower was highly successful and results in elite line development.

The sunflower is a strategically important oil crop. Every year the area under this crop grows, and the rapid returning of sunflowers back to the fields provokes the formation of new more aggressive races of broomrape ( Orobanche cumana Wallr.). Broomrape is a parasite that interferes with the normal development of sunflower and can lead to significant crop losses. For creating a sunflower hybrid (F 1 ) it is needed to cross the parental components, which have a complex of important traits, among which there is a resistance to the herbicides and a broomrape. Considering that the creation of each of the components of the hybrid involves many years of painstaking work in the breeding process, modern approaches and methods are used to accelerate the creation of a new source material. Thus, using the technology of cultivating immature embryos in vitro culture, it is possible to reduce the time to create lines resistant to herbicides, for example. And during selection for resistance to pathogenic organisms, testing is most often used against an artificial infectious background, both in the field and in laboratory conditions, in order to differentiate the material on this basis. The aim of this work was to establish the effectiveness system when creating an initial breeding material resistant to herbicides and broomrape. As a result of testing the lines on an artificial infectious background, was identified plants which have high resistance to the G-race broomrape and were isolated from hybrid combinations resistant to tribenuron-methyl and imidazolinones. Thus, among the analyzed plants which are resistant to tribenuron‐methyl, four lines were isolated, which are highly resistant to the G-race broomrape from a hybrid combinations BH0118/SURES–2 (101/1, 101/4, 101/6, 101/7), and BH0318/SURES–2 (101/21, 101/24, 101/28, 101/30), and five lines (101/11, 101/12, 101/16, 101/17, 101/18) from a hybrid combination BH0218/SURES–2. Among imidazolinone-resistant sunflower lines – line 3 was isolated as highly resistant to the G-race broomrape.

Over the past two decades, there was observed a widespread of rust on sunflower in some regions of Russia. The identification of the racial structure of Puccinia helianthi populations in Russia has not been done since the early 80s of the last century. At that time, races 100 and 300 were identified. In our recent study, in addition to these races, new biotypes: 700, 710, 722, 772 were identified for the first time. The purpose of this study is to determine the racial identity of 160 P. helianthi isolates collected from 2018 to 2020 in the Rostov, Saratov, and Krasnodar regions. We used eight standard differentiating lines of sunflower: SM-90, SM 29, R-386, HАR-1, HАR-2, HAR-3, HAR-4, HAR-5. Sunflower variety VNIIMK 8883 was used as a differentiator susceptible to all races of the pathogen. In addition to the six races mentioned above, we identified 11 more new races for the first time: 304, 351, 352, 364, 704, 736, 740, 741, 745, 760, 762. Race 700 prevailed among the isolates collected in the Rostov region in 2020; we also identified single specimens of races 760, 762. Thus, 17 races of P. helianthi were found on sunflower in three regions of the Russian Federation. Other races may be also present here, so further research is required.

Phyllody in sunflowers ( Helianthus annuus L.) is characterized by the appearance of bracts and ray flowers in the centre of the heads. It has been discussed for decades among the sunflower plant breeders and experts without a clear “unique” explanation for it. The erratic appearance of the phenomena has led to consider it either a disease or hybrid defect and the plants with Phyllody as off-types, raising several farmers claims to seed producers. However, the auxins gradient, in the growing Asteraceae heads, determines the differentiation pathway of the undifferentiated cells. i.e., bracts and ray flowers at the border and disk flowers in the centre of the head. Disruption of the natural auxin gradient alters the cell differentiation in the growing heads and causes bracts and ray flowers to grow where only disk flowers should grow. The disruption of the natural head bottom auxin gradients may be caused by small injures in the fast-growing head receptacle. The most common causes of Phyllody are hormonal herbicide damage and Boron (B) deficiency, even temporary. Plants growing with B deficiency have brittle cell wall and membranes while a plant with high B levels produces plastic or elastic cell wall and membranes. Brittle cell walls are susceptible to breaks during growth. Sunflowers genotypes may react to crack or small damages in the sunflower bud in two ways. Some tend to repair the damages by regrowing new organs such as ligules or bracts and forming Phyllody. Others do not regrow and only heal the wound creating the funnel hole head shape.

To find out the effect of EMS dosage on sunflower variety BARI Surjamukhi-2, different EMS concentrations were compared at the molecular biology laboratory (MBL), Oilseed Research Centre (ORC), Bangladesh Agricultural Research Institute (BARI), Gazipur. A total of 10 seeds were treated with each treatment and % germination, % survival and early seedling growth was investigated. Decreased % germination was found with the increasing dose of EMS for all the treatment compared to the control, except for T 4 (0.6% EMS) treatment where a 100% seed was found to be germinated. With an exception of treatment T 4 , a decreasing trend of % survivability with the increasing dose of EMS was observed. The gradual reduction with the increasing dose of EMS were observed for most of the studied characters such as leaf area, number of internodes, internode length, fresh and dry weight of leaf, dry weight of shoot, and fresh and dry weight of root in comparison to non-treated control seedlings. However, stimulatory effect with lower dosage of EMS was observed for shoot length in T 2 (0.2% EMS), root length in T 3 (0.4% EMS), and stem fresh weight in T 2 over control. Based on a quadratic regression analysis, using % survivability data, LD50 was calculated and optimum EMS dose was found 0.5%. Hence, the optimized EMS dose of 0.5% may be used to develop large scale desirable mutant of sunflower variety BARI Surjamukhi-2.

The effects of various concentrations of herbicide Euro-Lightning Plus on the state of microbiota in the root zone of sunflower have been studied. Soil of plant rhizosphere and interrow soil after treatment with the herbicide at the doses of 1.2 and 2.5 l/ha were taken for the analysis at the end of sunflower growing season. Rhizosphere soil without herbicide application was used as a control. The herbicide was applied at the stage of 2–4 true leaves. The total number of bacteria in the rhizosphere of control plants was 12.82 million CFU/g of soil while in the rhizosphere and in the interrow soil after herbicide treatment with a dose of 2.5 l/ha it decreased by 1.4–1.5 times. A general trend of decline in number of the basic ecological and trophic groups of bacterial microorganisms with the increase in a dose of herbicide was established. Microbiological coefficients that reflect the functional activity of the microflora indicate changes in its biological activity under the influence of the herbicide Euro-Lightning Plus, which leads to deterioration in the agroecological state of the studied soils. It was also found that herbicide application resulted in a rearrangement of micromycete complexes in the root zone of sunflower which led to a two-fold reduction, compared to the control, of mycobiota species diversity and the formation of a specific species composition of mycocenoses. A greater genus and species diversity of fungi of the microflora in the rhizosphere of control plants, in comparison with the herbicide-treated soil, was revealed. A reduction in species diversity of the genus Penicillium from six species in the control to 1–2 species in the rhizosphere of experimental sunflower plants as well as the absence of rare saprophytic fungi species from the genera Acremonium , Verticillium , Trichoderma and Paecilomyces were noted.