CHARACTERIZATION OF HYBRIDS, FORMS AND LINES, OBTAINED FROM INTERSPECIFIC HYBRIDIZATION OF CULTIVATED SUNFLOWER HELIANTHUS ANNUUS L. WITH WILD SPECIES OF GENUS HELIANTHUS M. Hristova-Cherbadzi University of forestry, Sofia, Bulgaria Correspondence to: Miroslava Hristova-Cherbadzi E-mail: mirahristova@yahoo.com ABSTRACT The interspecific hybrids, produced from crosses between cultivated sunflower (Helianthus annuus) and 16 wild species of genus Helianthus. The rate of cross-compatibility was different. The F 1 plants had an annual or perennial growth cycle, branched stem and different anthocyanin coloration, vegetation period and seed colour. The hybrid nature of the some F 1 plants was confirmed trough cytological, RAPD and electrophoretic analyses of seed storage proteins. Breeding of the new sunflower forms and lines was carried out through backcrossing to cultivated sunflower, self-pollination and sib-pollination and selection in generations. Most of the new obtained lines were resistant to some fungal diseases and the parasite Orobanche cumana and had high combining ability. It was established that some of them carried Rf genes for CMS Pet-1. Genes that controlled such characters as period of vegetation, plant height, type of branching, size and form of inflorerescence and seeds, high seed oil content were transferred, too. These characters make the lines suitable to including for heterosis breeding in sunflower. Keywords: Helianthus, interspecific hybridization, resistance, sunflower Introduction The Helianthus species were used as source for genes determining interesting characteristics, in the middle of the last century. The genus Helianthus contains 51 species (25). The results from the investigations showed that this wild species carried characteristics as resistance to different diseases, parasites, pests, herbicides and abiotic stress factors (1, 2, 7, 12, 22, 23, 24, 27, 28, 29 and etc.). Helianthus species were distinguished with their great diversity, different quantity and quality of seed oil and seed protein content (11 and etc.). They possessed the genetic system CMS - restorers of fertility (9, 13, 20, 21 and etc.). Part of these characteristics was already transferred to cultivated sunflower and on that basis the new sunflower forms and lines were developed (3, 8, 10 and etc.). Materials and methods Plant material Cultivated sunflower: The cultivars used in this investigation were Peredovik and VNIIMK 6540 as well as the lines and they sterile forms - 2607, 6075, 6116, 6234, НА 89 and HA402. Wild species: The wild Helianthus species from the collection of Dobroudja Agricultural Institute, General Toshevo used in t his investigation were included in Тable 1. The investigation encompassed the period 1999-2008. Hybridization was carried out through reciprocal crosses realized under field conditions. Hybrid plants were grown and regular phenological observations were performed during the vegetation. Biometric parameters and description of the main morphologic characters and biologic peculiarities were performed, as well as on laboratory measurements of whole plants and their seeds. Presence of sources of fertility restorer genes (Rf) for CMS Pet-1 was also registered. Female fertility of the plants was determined by the amount of seeds obtained after free pollination. Oil content of seeds and 1000 seed weight were estimated. Phytopatological characterization included evaluation of the resistance to Plasmopara helianthi, Phomopsis helianthi, Phoma helianthi, Sclerotinia sclerotiorum and to the parasite Orobanche cumana. SPECIAL EDITION/ON-LINE 112 120 YEARS OF ACADEMIC EDUCATION IN BIOLOGY
Electrophoretic analyses of seed storage proteins and RAPD of F 1 plants and their parents were performed to prove their hybrid nature. Cytological characterization investigations were mainly carried out with the aim to determinate chromosome number of F 1 hybrids, to study the meiosis of pollen female cells of F 1 - chromosome conjugation (number of the bivalents, threevalents, quadrivalents, univalents and hyasmas), fast and lagging chromosomes, chromosome bridges, to determinate pollen viability. Breeding of the new sunflower forms and lines was carried out through backcrossing to cultivated sunflower, self-pollination and sibpollination and selection in generations. The aim was developing new B and R lines and sterile analogues (A lines) of B lines. TABLE 1 Species from genus Helianthus crossed with H. annuus Groups of species Species Annual species (2n=34) H. bolanderi, H. neglectus, H. petiolaris Perennial diploid species (2n=34) H. divaricatus, H. giganteus, H. glaucophyllus, H. maximiliani, H. nuttallii ssp. rydbergii, H. occidentalis ssp. plantagineus, H.pumilus Perennial tetraploid species (2n=68) H. decapetalus, H. hirsutus, H. laevigatus Perennial hexaploid species (2n=102) H. ciliaris, H. x laetiflorus, H. pauciflorus ssp. rigidus, H. pauciflorus ssp. Results and Discussion The analysis of the results presented in table 2 shows that the 16 wild Helianthus species could be crossed with H. annuus. The crossability rate and seed set was different and depended not only on the number of chromosomes in the species. There were probably other factors, which influence the forming of the zygote. Seeds were obtained at both directions of crossing and hybrid plants - only in the direct crosses when H. divaricatus, H. glaucophyllus, H. maximiliani, H. nuttallii, H. occidentalis, H. pumilus was used. Higher percentages and numbers of hybrid plants were obtained when cultivated sunflower was used as a female parent with the exception of the hybrids with the participation of all perennial tetraploid species, as H. laetiflorus and H. pauciflorus ssp. rigidus. The hybrids with the perennial H. nuttallii constitute a real contribution to interspecific hybridization because successful hybridization with this wild species had been reported for first time (18). The implementation of interspecific hybridization in sunflower was accompanied by certain difficulties such as lack of crossability of the species, different rates of sterility, low vitality of F 1 hybrids, tendency of returning back to parents and etc. The possibilities and problems in the hybridization of cultivated sunflower with species of the genus Helianthus were discussed (6 and etc.). The characterization of some hybrids was published (4, 5, 14, 16, 17, 19). The F 1 plants had an annual or perennial growth cycle, branched stem and different anthocyanin coloration, vegetation period and seed colour. The presence of branching and anthocyanin in the genotype of F 1 hybrids from right crosses proved the transfer of genetic material from wild species and was a suitable morphological marker. The hybrid nature of F 1 plants were proved by electrophoretic analyses of seed storage proteins and RAPD method. The results confirmed that there was a polymorphism. The F 1 plants were also cytological investigated. Reduction division of PMC in the F 1 plants occurred with deviations. Use of right crosses increases the rate of changes in the nuclear material, which favors heterosis selection and use of cytoplasmic male sterilite (CMS) in the sunflower. Reciprocal crossing offers additional possibilities for changing sunflower properties controlled by cytoplasmic genes. Such crosses could be used for finding new CMS sources. Up to 2005, 72 CMS sources in sunflower have been reported and described by different authors. Most of these them were derived from interspecific crosses (26). New sunflower CMS source with H. hirsutus origin was found (15). It was found out that 18 accession of 16 Helianthus species carried Rf genes for CMS from H. petiolaris (Pet-1). Breeding of the new sunflower forms and lines was carried out through backcrossing to cultivated sunflower, self-pollination and sib-pollination and selection in generations. Most of the new obtained forms and lines were resistant to some economically important fungal diseases and the parasite Orobanche cumana and had high combining ability, and new plant architectonics. It was established that some of them carried Rf genes for CMS Pet-1 (Table 3). Genes that controlled such characters as period of vegetation, plant height, type of branching, size and form of 113 120 YEARS OF ACADEMIC EDUCATION IN BIOLOGY SPECIAL EDITION/ON-LINE
inflorerescence and seeds, new plant architectonics, various colour of ray florets, high seed oil content were transferred, too. These characters make the obtained lines suitable to including for heterosis breeding in sunflower. Some of them were included in a program of development new hybrids suitable for growing in the most important sunflower production regions in the world. Developing of sterile analogues (A lines) of B lines began with determining of the fact that in the studied hybrid material Rf genes were absent. TABLE 2 Crossability of cultivated sunflower H. annuus and wild Helianthus species Crosses Pollinated inflorescences Seed set Total Hybrid plants total number with seed number % mean number % number of seeds number % Cultivated sunflower x Diploid annual species Helianthus H. annuus x H. bolandery 8 6 75.00 108 8.07 648 319 49.23 H. bolandery x H. annuus 12 7 58.33 21 10.61 147 37 25.17 H. annuus x H. neglectus 5 4 80.00 102 7.61 408 263 64.46 H. neglectus x H. annuus 8 4 50.00 14 8.09 56 18 32.14 H. annuus x H. petiolaris 12 8 66.67 91 6.80 728 431 59.20 H. petiolaris x H. annuus 11 6 54.55 15 7.39 91 21 23.08 Cultivated sunflower x Diploid perennial species Helianthus H. annuus x H. divaricatus 5 3 60.00 14 1.05 42 9 21.43 H. divaricatus x H. annuus 6 4 66.67 3 4.05 12 0 0 H. annuus x H. giganteus 5 4 80.00 12 0.90 48 6 12.50 H. giganteus x H. annuus 5 3 60.00 7 3.48 21 1 4.76 H. annuus x H. glaucophyllus 4 3 75.00 4 0.29 12 3 25.00 H. glaucophyllus x H. annuus 5 2 40.00 2 4.35 3 0 0 H. annuus x H. maximiliani 8 8 100 18 1.32 142 27 19.01 H. maximiliani x H. annuus 12 9 75.00 11 3.98 100 0 0 H. annuus x H. nuttallii 24 18 75.00 6 0.47 109 36 33.03 H. nuttallii x H. annuus 12 7 58.33 4 3.31 28 0 0 H. annuus x H. occidentalis 4 2 50.00 6 0.42 12 3 25.00 H. occidentalis x H. annuus 8 3 37.50 5 3.69 17 0 0 H. annuus x H. pumilus 6 4 66.67 7 0.52 28 5 17.86 H. pumilus x H. annuus 20 11 55.00 2 3.57 23 0 0 Cultivated sunflower x Tetraploid perennial species Helianthus H. annuus x H. decapetalus 7 6 85.71 15 1.12 90 17 18.89 H. decapetalus x H. annuus 9 5 55.56 6 8.33 30 7 23.33 H. annuus x Н. hirsutus 8 8 100 37 2.73 296 61 20.61 Н. hirsutus x H. annuus 7 5 71.43 9 6.98 45 14 31.11 H. annuus x H. laevigatus 11 9 81.82 21 1.57 190 52 27.37 H. laevigatus x H. annuus 15 8 53.33 5 7.35 40 13 32.50 Cultivated sunflower x Hexaploid perennial species Helianthus H. annuus x H. ciliaris 6 4 66.67 21 1.57 84 15 17.86 H. ciliaris x H. annuus 15 9 60.00 17 12.88 152 3 1.97 H. annuus x H. laetiflorus 5 5 100 23 1.72 115 28 24.35 H. laetiflorus x H. annuus 2 2 100 24 12.06 48 12 25.00 H. annuus x H. pauciflorus ssp. rigidus 6 6 100 38 2.84 228 72 31.58 H. pauciflorus ssp. rigidus x H. annuus 4 4 100 26 15.57 104 39 37.50 H. annuus x H. pauciflorus ssp. 6 6 100 17 1.24 102 24 23.53 H. pauciflorus ssp. x H. annuus 5 3 60.00 14 12.73 42 9 21.43 TABLE 3 Characteristics of some new B and R lines produced from interspecific hybridization SPECIAL EDITION/ON-LINE 114 120 YEARS OF ACADEMIC EDUCATION IN BIOLOGY
Nо Origin Plant height (cm) B lines Head diameter (cm) Seed oil content (%) M-8-A1 H. neglectus 130 21 49.32 113 3291 B Н. hirsutus 110 23 50.60 118 2942 B H. pauciflorus ssp. 140 24 52.47 116 HA 89 B Standard 110 24 49.80 114 R lines PR 35/5 H. divaricatus 125 16 51.65 109 PR 51/5 H. neglectus 120 16 48.62 109 1018 R H. nuttallii 140 16 53.43 106 2499 R H. pauciflorus ssp. Vegetation period (days) 130 22 52.32 105, unbranched 2505 R H. nuttallii 135 15 60.84 104 2879 R H. pauciflorus ssp. 125 16 52.09 110 3209 R H. neglectus 120 12 53.90 102 3291 R Н. hirsutus 120 21 50.60 108, unbranched 147 R Standard 135 17 46.30 108 The new ornamental sunflower forms were obtained from crosses between wild species H. petiolaris, H.giganteus and H. nuttallii and H. annuus in different generations. The morphological mutations were inherited steadily and suitable for markers. This is the good discernable characteristics as funnel-shaped form of ray flowers (1018 R), light lemon yellow of ray flowers (1070 R) and stipules winglet, posited in the basis of the leaves (2521R and 2522 R). The conclusion of this investigation is that wild species represent genetic potential available to introgress diseases resistance genes or other major agronomic traits in the cultivated sunflower. Acknowledgment I would like to thank Dr. Christov and Dr. Batchvarova who help me in my work. REFERENCES 1. Пустовойт Г. (1975) В кн. Подсолнечник (Пустовойт В.С.), Колос, Москва, 164-209. 2. Христов М. (1990) Дисертация за получаване на научна степен к. с. н., София. 3. Христов М., Христова-Чербаджи M. (2005) Научни трудове, 5, 73-78. 4. Христова-Чербаджи М., Вълкова Д. (2006) Field Crops Studies, III, 533-537. 5. Христова-Чербаджи М. (2007) Дисертация за придобиване на степен Доктор, БАН, София. 6. Christov M. (1991) Helia, 14(15), 35-40. 7. Christov M. (1996) In: Compositae (P. Caligari, D. Hind, eds), Royal Botanic Gardens, Kew, 547-570. 8. Christov M. (1996) In: Compositae (P. Caligari, D. Hind, eds), Royal Botanic Gardens, Kew, 603-608. 9. Christov M. (1999) Helia, 22(31), 1-12. 10. Christov M. (2008) Helianthus species in breeding research on sunflower. Proceedings of the 17 th International Sunflower Conference, Cordoba, Spain, 709-714. 11. Christov M., Ivanova I., Ivanov P. (1993) Helia, 16(18), 63-70. 12. Christov M., Sabev G., Valkova D., Hristova- Cherbadzi M. (2008) New sunflower forms and hybrids, resistant to herbicides. Proceedings of the International Conference, Novi Sad, Serbia, 329-331. 13. Fick G., Zimmer D., Dominguez-Gimenez J., Rehder D. (1974) Fertiliti restoration and variability for plant and seed characteristics in wild sunflower. Proceedings of the 5 th International Sunflower Conference, Bucharest, 333-338. 115 120 YEARS OF ACADEMIC EDUCATION IN BIOLOGY SPECIAL EDITION/ON-LINE
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