Interspecific hybrid between cultivated sunflower (Helianthus annuus L.) and silver leaf sunflower H. argophyllus T. & G.: Cytomorphological and molecular characterization

Abstract

Successful interspecific hybrids were obtained through
hybridization between cultivated sunflower (Helianthus
annuus L.; 2n=2x=34) variety ARM-243B and a wild species
(H. argophyllus; 2n=2x=34) accession no. PI-468649 for
transferring desirable traits like downy mildew resistance,
oil content and hopper resistance from wild species into
cultivated background. Morphological, cytological and
simple sequence repeats (SSR)-based molecular analyses
were carried out to confirm the hybrid nature of the F1
plants. The hybrids exhibited morphological features
intermediate to both the parents for few attributes and
showed greater similarity to wild Helianthus species for
traits like leaf and stem hairiness, flower colour, stem size,
branching, disc floret pigmentation, plant height, seed size
and seed shape, etc. A reduction (89.9%) in pollen fertility
was recorded in F1 plants. Meiotic analysis revealed the
presence of univalents, bivalents, trivalents and
quadrivalents in all the pollen mother cells (PMCs) analysed.
Multivalents were observed in few PMCs, indicating
segmental homology between chromosomes. Higher level
of chromosome configurations like quadrivalents were
observed in 42 out of 50 PMCs. Frequently observed
chromosome configurations in diakinensis were 15 II + 1 IV
and 13 II + 2 IV. The results suggested that the species H.
argophyllus and H. annuus differ by 1-2 translocations.
SSR primers ORS-05, ORS-896 and ORS-908 were found to
reveal highly polymorphic bands in the parents.