Cytogenetic study of helianthus strumosus and its F1 and BC1F1 hybrids with cultivated sunflower

Abstract

Helianthus strumosus L. is represented in Novi Sad collection of wild sunflower species with large number of accessions (14 with seed reserves and 20 in the field collection). It is often used as a source of resistance to disease-causing agents in the breeding of cultivated sunflower. Interspecific crosses with cultivated sunflower lines were performed using 17 accessions of this species. Six F1 hybrid combinations were obtained using twoH.strumosus accessions with a total of 48 plants, while in backcrossing 51 BC1F1 plant was obtained. Nine originated from crossing F1 and 42 from crossing F1OP with cultivated sunflower. Cytogenetic analysis showed 3 levels of ploidy in the examined accessions of H.strumosus (n = 17, 34 and 51) and high pollen viability ranging from 83.13- 98.93%. F1 hybrids exhibited reduced pollen viability (26.83 - 55.34%), and there were occurrences of male sterility. Analysis of chromosomal association of F1 hybrids showed that chromosome number was 68, and that most commonly observed associations were 25-34 bivalents with the occurrence of quadrivalents, hexavalents and univalents.