Ploidy analysis of Helianthus species by flow cytometry and its use in hybridity confirmation

Abstract

Sunflower (Helianthus annuus L.) is one of the most important oilseed crops cultivated worldwide. It is one of the few crops that has been improved for several characteristics through interspecific hybridization. In the present investigation, the ploidy of 43 Helianthus species belonging to diploid, tetraploid and hexaploid status along with 2 accessions of cultivated sunflower was determined. As wide variation exists in the Helianthus species for vegetative characteristics including pigmentation, processing of the leaf samples was tried with incorporation of 1 % polyvinylpyrrolidone while chopping the leaf which gave sharp peaks with low coefficient of variation. Ploidy as determined by flow cytometry was in agreement with the reported status of the Helianthus species used in the study. The mean 1C values for diploids, tetraploids and hexaploids were 3.67, 6.73 and 10.07 pg, respectively. The technique was validated on an interspecific hybrid of cultivated sunflower (2n = 2x) with H. hirsutus (2n = 4x) which confirmed the triploid status of the hybrid.