Chromosome stability of in vitro propagated Cucurbita cultivars

Abstract

Cucurbita pepo L., a member of Cucurbitaceae family, is an annual plant with herbaceous stems, broad leaves and superficial scattered roots. Monoecious flower structure in the Cucurbitaceae family and the differences in the maturing time of male and female organs in flowers cause an increase in the foreign fertilization rate. Therefore, there may be positive or negative changes in the existing characteristics of the species. Micropropagation method can be performed in pumpkin species for clonal propagation, but their genetic stability in tissue culture is an important consideration. Chromosome number and morphology are primary cytogenetic parameters that must remain stable after in vitro propagation. We preformed cytogenetic analysis of different hybrid pumpkin genotypes cultivated in our country (Ardendo, Angelina, Torpido, Roni, Sena Hanım) in order to determinate their chromosome stability level. Cotyledon nodes, nodes, shoot apex, hypocotyl and internode explants were prepared from the 4-week old C. pepo seedlings by making a horizontal slice through the hypocotyl region. The highest shoot and callus regeneration was obtained in Torpido genotypes in cotyledonary node explants produced multiple shoots placed in tissue culture media MS+1 mg/l N6-benzylamino-purine BA. The chromosome number and karyotype analysis were determined in control and in vitro propagated Cucurbita pepo L. plants and ploidy levels were confirmed to be 2n = 40.