Daniel Cohen

Bio: Daniel Cohen is an academic researcher. The author has contributed to research in topics: Shoot & Micropropagation. The author has an hindex of 4, co-authored 4 publications receiving 131 citations.

Intra-varietal variation for in vitro plant regeneration in the genus Trifolium

Abstract: Seedlings of Trifolium repens showed considerable variation with regard to the morphology and growth of their calli, and their ability for in vitro differentiation of shoots. One of the lines selected for regeneration in primary callus cultures also showed shoot formation from protoplasts. Somatic embryogenesis in callus cultures of T. pratense and T. arvense occurred only in selected seedling lines. This paper highlights the importance of screening a large number of plants within a cultivar of outbreeding species to achieve reproducible plant regeneration from tissue culture.

A genetic analysis of cell culture traits in tomato.

Abstract: Tomato genotypes superior in regenerating plants from protoplast and callus cultures were obtained by transferring regeneration capacity from Lycopersicon peruvianum into L. esculentum by classical breeding. The genetics of regeneration and callus growth have been studied in selfed and backcross progenies of a selected plant (MsK93) which has 25% L. peruvianum in its ancestry. Segregation data showed that the favourable cell culture traits of L. peruvianum are dominant. Regeneration capacity from established callus cultures was controlled by two dominant genes. Callus growth on primary expiants, callus growth of established cultures and shoot regeneration from explants had high heritabilities (0.47, 0.78, 0.87, respectively). Callus growth and regeneration capacity were not correlated within the populations studied.

Rejuvenation and Micropropagation

Abstract: Cloning in vivo and in vitro of adult or mature woody plants is adversely affected by characteristics accompanying maturation such as reduced growth rate, reduced or total lack of rooting ability or sometimes the unpleasant phenomenon of plagiotropy (1, 2). Maturation, a complex phenomenon, is the major problem preventing a wider application of tissue culture technology among woody spieces. Despite the problems mentioned, the possibility of multiplying mature trees by cloning and establishing field trials with micropropagated material, has been demonstrated e.g. for eucalypts (3), Tectona grandis (112) Sequoia sempervirens, Pinus pinaster and Pinus radiata (4, 5). Success with these trees has been achieved mainly by the use of special starting material e.g. from the base of the tree, by special pre-treatment in vivo and/or by in vitro culture (6). All of these tricks, which improve propagation are often described by the general term rejuvenation; a term which is difficult to appreciate since it usually does not say what it in fact entails. However, it is clear that rejuvenation is a prerequisite for possible cloning of adult trees and that the success in practice will mainly depend on the ability to rejuvenate them (7, 8, 9, 10).

Effect of genotype on somatic embryogenesis from immature cotyledons of soybean

Abstract: Genotype has a large effect on the ability of immature soybean cotyledons to undergo auxin-stimulated somatic embryogenesis. Among 33 soybean lines, all those showing good regeneration were found to have in their pedigrees one or both of the highly regenerative ancestral lines, ‘Manchu’ or ‘A.K. Harrow’. When ‘Manchu’ was crossed with ‘Shiro’, a genotype showing extremely poor regeneration, F1 hybrid cotyledons showed intermediate regeneration capacity.

Micropropagation of garlic through in vitro bulblet formation

Abstract: We developed a novel micropropagation method for garlic (Allium sativum L.) by the combination of initial shoot-tip culture, shoot multiplication and in vitro bulblet formation. Garlic shoot-tips were cultured on LS medium containing 1 μM indole-3-acetic acid (IAA) and 1 μM 6-benzyladenine (BA) to regenerate proliferative shoots. These shoot-tips produced multiple shoots when transferred to modified LS medium containing 5 μM 1-naphthaleneacetic acid (NAA) and 10 μM BA, and cultured at 20°C under 12-h light conditions. Higher ratios of KNO3/NH4Cl in the media promoted multiple shoot formation, together with suppressing vitrification of these shoots. The proliferated shoots of early maturing cultivars produced bulblets by culture on LS growth regulator-free medium at 25°C under 16-h light. On the other hand, the late maturing cultivar, Howaito-roppen, formed bulblets after a low temperature treatment of the proliferated shoots for 6 months followed by culture on LS medium containing 6 to 12% sucrose for two months. The dormancy of the bulblets of cv. Howaito-roppen was broken by successive treatments at a high (35°C), a middle (20°C), and then a low (5°C) temperature.