Cytogenetic study of hexaploid species Helianthus tuberosus and its F1 and BC1F1 hybrids with cultivated sunflower, H. annuus

Abstract

Helianthus tuberosus is a potential source of resistance to many disease-provoking pathogens. Three accessions of H. tuberosus were used in this research and they were crossed with cultivated sunflower. Six F] and two BC1F1 hybrid combinations were obtained. Analysis of meiosis was performed using aceto-carmine method (GEORGIEVA-TODOROVA, 1976) and pollen viability was determined by staining method of ALEXANDER (1969). Meiosis was regular in cultivated sunflower and the pollen viability was high (96.8-98.9%). Low percent of irregularities was found in the meiosis of H. tuberosus. Pollen viability was high (97.2-98.7%). Chromosome pairing was mostly regular in F1 hybrids (34 bivalents), but some meiocytes contained 28-32 bivalents with uni- and quadrivalents present. The percent of meiocytes with fast chromosomes in metaphase was 24.6-87.2, with lagging chromosomes in anaphase I 10.5-81.0 and in telophase 25.0-33.3. Chromosome bridges were detected in 0-9.9% of meiocytes in anaphase. Pollen viability in F1 hybrids ranged from 27.0 to 47.9%. In BC1F1 hybrids number of bivalents was 16-25, univalent 2-18 and multivalent 0-1. Although a triploid set of chromosomes (51) was expected in BC1F1 hybrids, number of chromosomes was 45-57. Pollen viability varied from 0 to 54.3%.

H. tuberosus predstavlja potencijalni izvor otpornosti prema mnogim prouzrokovačima bolesti. U istraživanjima su korišćene tri populacije vrste H. tuberosus koje su ukrštane sa gajenim suncokretom. Dobijeno je 6 hibridnih kombinacija F1 i 2 BC1F1 gen. Izvršena je analiza mejoze acetokarmin metodom (Georgieva-Todorova, 1976) i vitalnosti polena bojenom metodom (Alexander, 1969). Mejoza kod gajenog suncokreta proticala je normalno, a vitalnost polena bila visoka (96.8-98.9%). Kod vrste H. tuberosus mejoza je proticala uz nizak % nepravilnosti tipa neuključenih hromozoma. Vitalnost polena je bila visoka (97.2-98.7%). Kod F1 hibrida najčešće je bilo normalno parenje hromozoma (34 bivalenta), a zabeležene su mejocite sa 28-32 bivalenta uz pojavu uni- i kvadrivalenata. Procenat mejocita sa izbeglim hromozomima u metafazi I je bio 24.6-87.2, sa izostalim hromozomima u anafazi I 10.5-81.0, a u telofazi II 25.0-33.3. Hromozomski mostovi su detektovani u 0-9.9% anafaznih mejocita. Vitalnost polena kod FI hibrida se kretala od 27.0-47.9%. Kod BC1F1 hibrida broj bivalenaca je bio od 16-25, univalenata od 2-18, a multivalenata od 0-1. Iako je očekivan triploidan broj hromozoma (51) kod BC1F1 hibrida broj hromozoma je bio od 45-57. Vitalnost polena se kretala 0-54.3%.