Some correlation between the susceptibility of samples to Phomopsis and length of their vegetation period is being detected. According to data received in 2009 distribution of Phomopsis in the nursery of middle-early samples with the vegetation period of 92-106 days was 37 %. In nursery of middle-late large seeded samples (vegetation period – 106–117 days) affection by Phomopsis was 58%. The latest confectionery varieties of the Chinese development (vegetation period – 123–130 days) showed 100% affection. Quantity of samples in each ripeness group was 30–50. At the same time many ultra-early ripening samples with period of 75–80 days between shoots and ripening are not affected by Phomopsis because they manage to finish flowering and formation of achenes by the moment of the disease emergence. We can’t rate these samples as resistant until they are tested by a severe infectious background.
Table 3. Sunflower collection samples which showed resistance to Phomopsis
(Kuban experimental station of VIR, 2008)
| No. | Origin | Catalogue No. | Status | Affection by Phomopsis, % | Vegetation period (shoots – ripening), days |
| 1 | France | 1883 | Population | 0 | 117 |
| 2 | Germany | 1957 | Population | 0 | 95 |
| 3 | Armenia | 2219 | Population | 0 | 100 |
| 4 | Ukraine | 2678 | Population | 0 | 102 |
| 5 | Armenia | 2865 | Population | 0 | 116 |
| 6 | Canada | 2302 | Line SM 198 | 0 | 100 |
| 7 | France | 2346 | Population | 10 | 102 |
| 8 | Russia | 2052 | Variety Smena | 14 | 100 |
| 9 | Belarus | 1693 | Population | 14 | 112 |
| 10 | Poland | 2493 | Line L-337 | 14 | 91 |
| 11 | Moldavia | 1971 | Population | 17 | 101 |
| 12 | Argentina | 2547 | Population | 20 | 112 |
According to the results of the ecological test of lines RILs developed in France on base of interspecific hybrids we have sampled 11 lines which had not been affected by Phomopsis in years 2000–2007 and were included into the collection of the resistance sources in 2008. Under conditions of 2009 tolerance to Phomopsis was shown only by five of them: RIL 273, RIL 440, LR1, RIL 270 and RIL 342. Other six lines were affected from 3 to 22%. According to the long-term annual observations only 12 samples haven’t been affected by Phomopsis (table 4).
Table 4. Sources of sunflower resistance to Phomopsis
(Kuban experimental station of VIR, 2009)
| Name, origin | Catalogue No. | Vegetation period, days | Weight of thousand seeds, g | Plants height, cm | Affection by Phomopsis, % |
| Variety Zelenka | 552 | 100 | 62 | 180 | 0 |
| VIR 365 | 3326 | 106 | 59 | 150 | 0 |
| VIR 249 | 3469 | 107 | 62 | 140 | 0 |
| VIR 449 | 3527 | 105 | 59 | 133 | 0 |
| VIR 448 | 3487 | 107 | 39 | 120 | 0 |
| VIR 114 x H. giganteus | 3570 | 98 | 65 | 115 | 0 |
| VIR 130 | 3595 | 96 | 62 | 162 | 0 |
| LR1, France | 3571 | 103 | 28 | 105 | 0 |
| RIL 440, France | 3614 | 92 | 40 | 120 | 0 |
| RIL 270, France | 3615 | 103 | 48 | 143 | 0 |
| RIL 342, France | 3616 | 101 | 38 | 160 | 0 |
| RIL 273, France | 3617 | 102 | 30 | 170 | 0 |
| Control, VK - 571 | 3511 | 88 | 63 | 110 | 98 |
| Standard variety Master | 3553 | 103 | 79 | 197 | 14 |
Collection of resistant sources includes old variety Zelenka (catalogue number 552), five lines developed at the Kuban station, an interspecific hybrid VIR 114 x H. giganteus of the eleventh inbreeding generation and five lines of French development. The interspecific hybrid is a mid ripening, nonbranched, well adjusted over the morphological traits introgressive line of the eleventh inbreeding generation. Line VIR 130 was sown in quantity of eight generations of different plants. Splitting on resistance to Phomopsis was identified: four generations didn’t display any affection symptoms, and four ones had a low affection degree: 3, 4, 8 and 15%. In 2009 four generations of line VIR 130 selected on tolerance to Phomopsis didn’t show affection symptoms. The control sample (VK-571, catalogue number 3511) was 98% affected in 2009, standard variety Master – 14%. Some samples of the resistance sources collection have other valuable breeding traits. Lines VIR 365, VIR 249 and VIR 449 are donors of genes of pollen fertility restoration for CMS PET 1 and can be used as paternal forms by developing sunflower hybrids resistant to Phomopsis. Line VIR 448 is ornamental and is recorded in the State register of selection achievements as variety Solnyshko. Line VIR 130 has a sterile analog based on CMS PET 1 and some marker morphological traits: low arcuate branching, anthocyanic color of hypocotyl and tubular flowers, stronger leaf venation, orange-yellow false ray flowers, deformed head, white seeds.
Phomopsis resistance in variety Zelenka (No. 552) and lines developed at the station: VIR 365 (No. 3326), VIR 448 (No. 3487) and VIR 449 (No. 3527) was confirmed by the results of evaluation under conditions of artificial inoculation at the immunity laboratory of VNIIMK (table 5).
Table 5. Evaluation of samples from the sunflower collection at the seed ripening stage on the resistance to Phomopsis under the artificial inoculation (VNIIMK, 2006)
| Name of sample | Catalogue No. | Percentage of stems affected by Phomopsis under the inoculation | |
| With mycelium into the petiole | With ascospores from the artificial infectious background | ||
| Variety Zelenka | 552 | 0 | 0 |
| VIR 449 | 3527 | 4 (2)* | 0 |
| VIR 249 | 3469 | 5 (2) | 0 |
| VIR 365 | 3326 | 7 (2) | 0 |
| VIR 448 | 3487 | 14 (2) | 0 |
| VK 571, control | 100 (4) | 100 (4) | |
| * - In brackets there is given degree of stem affection; degree 2 at the seed ripening stage shows that material is resistant | |||
Thus, old variety Zelenka developed at the Veydelevsky experimental station and lines VIR 249, VIR 365, VIR 448 and VIR 449 developed at the Kuban station as lines-restorers of pollen fertility breeding on heterosis refer to the samples resistant to Phomopsis according to data received in the course of field evaluation and results of testing in the xonditions of severe infectious background.
DISCUSSION
It has been shown earlier that plants resistant to Phomopsis are characterized by the thicker collenchyme, presence of vital cell layer in pith and late lignification of pericycle, that’s why early ripening forms of sunflower are affected stronger than late ripening ones (Dоzеt, 1996; Antonova, 1999). Data given above also indicate the correlation between the resistance of samples and length of their vegetation period. Perhaps, it is caused by different weather conditions during the vegetation period, in particular by the correlation between air humidity and temperature (hydrothermal coefficient) that influence spread of the infection. E.G. Dolzhenko came to the similar conclusion in his work (2000). Phenotypes of resistant varieties and lines from the VIR collection do not correspond to the “stay green” mutation, for which a close correlation with the absence of affection by pathogen has been established (Miller & Fick, 1997). Based on our observations, it should be noted that we can’t talk about resistance or susceptibility of the species taken as a whole. Most likely, resistance is attributable to various populations or even plants of given species which should be used as sources of resistance.
ACKNOWLEDGMENTS
The research was partly held with financial support from the International Science and Technology Center (ISTC), grant 3034.
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