Cytomorphological and molecular characterization of interspecific hybrids between Helianthus annuus L. and H. argophyllus T. & G.

Abstract

Phenotype, chromosome pairing and pollen fertility were compared between parental populations and F1 hybrids of interspecific cross between Helianthus argophyllus T. &G. (PI-468651) and cultivated sunflower. The main purpose of this sturdy to transferring desirable traits like drought tolerance, downy mildew resistance and leaf hopper resistant from wild Helianthus species into cultivated background. The hybrids exhibited morphological features intermediate to both the parents for few attributes and more related to wild Helianthus species like, leaf and stem hairiness, flower colour, stem size, branching, disc floret pigmentation, plant height, seed size and seed shape, etc. The analysis of meiosis revealed that the crossed species differed for the chromosome level. In the diakinesis of F1 plants, besides bivalents, a small percentage (6.7%) of univalent and multivalent chromosome configurations were found. Similar percent of fast and lagging chromosomes and chromosome bridges were found in other phases of meiosis. Trivalents and univalents were rarely observed. Irregular chromosome pairing was found in less than 10% of meiocytes of F1 hybrids. A reduction (90.1%) in pollen fertility was recorded in F1 plants as compared to both the parents. Hybridity of interspecific hybrids was confirmed through sunflower specific molecular markers. Primer, ORS-677 revealed polymorphism between the parents and was used for confirmation of hybridity of the F1s. 90 informative SSR markers screened in the study will be useful marker resources for tracking the flow of H. argophyllus genetic material among the progenies that may be produced by future backcrosses to H. annuus. Results show that the classical method of crossing is applicable in sunflower breeding programs for obtaining interspecific hybrids.