, R. Kumar, K. 1996 Embryo rescue in plants—a review Euphytica 89 325 337 Sinclair, J.W. Byrne, D.H. 2003 Improvement of peach embryo culture through manipulation of carbohydrate source and pH HortScience 38 582 585 Yaseen, M. Ahmad, T. Sablok, G
Margarita Pérez-Jiménez, Alfonso Guevara-Gázquez, Antonio Carrillo-Navarro, and José Cos-Terrer
Yujie Yang, Donglin Zhang, Zhihui Li, Xiaoling Jin, and Jinying Dong
months followed by 3 months cold stratification at 4 °C produced 90% germination ( Dirr and Heuser, 2006 ). Breeding programs using this protocol usually last many years. For more than 50 years, embryo culture techniques have been successfully applied to
Iwao Oiyama, Shozo Kobayashi, Katsuichi Yoshinaga, Toshifumi Ohgawara, and Shigetaka Ishii
Ahmed A. Obeidy and M.A.L. Smith
The regenerative capacity of mature pecan [Carya illinoinensis (Wangenh.) K. Koch] embryonic tissues was demonstrated after pretreating mature nuts to eliminate associated endogenous contaminants. Cultured cotyledon segments were induced to form adventitious roots in a medium with 50 μm NAA. A regeneration medium with 20 μm BA and 5 μm IBA stimulated prolific axillary shoot production from the embryonic axis without causing cotyledon abscission. Cotyledon retention was essential for shoot initiation and long-term development. Eighty-five percent of the shoots emerging from embryonic axes formed at the cotyledonary nodes. Thirty percent of the microshoots rooted on an auxin-free medium after preculture in a medium with 20 μm IBA. TDZ (25 μm) stimulated callus production from the cotyledonary nodes and radicles. Adventitious buds emerged on the callus surface and internally in callus. Chemical names used: a -naphthaleneacetic acid (NAA); 6-benzylaminopurine (BA); indole-3-butyric acid (IBA); N-phenyl-N'-1,2,3-thidiazol-5-ylurea (TDZ).
Kenneth W. Mudge and Chin-Chang Chu
In vitro asymbiotic seed germination, subculture, and outplanting of orchids is presented as a laboratory exercise suitable for students of plant propagation or tissue culture. Dendrobium antennatum (Lindley), Phalaenopsis (Blume) white hybrid, or both, are used in this exercise because they flower predictably in the greenhouse, are reliable for seed production, and germinate and grow rapidly in vitro. The exercises can be used to instruct students in the skills involved in orchid seed sterilization, sowing, and culture, as well as instruct students in the unique features of orchid reproductive biology and symbiosis. A schedule is suggested for stock plant flower pollination, capsule harvest, seed sowing, and seedling subculture so that the necessary plant material is available for students to sow, subculture, and outplant seedlings during a single laboratory session.
Alberto C.Q. Pinto, Suzanne M. Dethier Rogers, and David H. Byrne
The influence of medium formulation, methods of ovule support, and ovule perforation on in vitro growth of immature peach [Prunus persica (L.) Batsch] embryos (4.0 to 8.7 mm long) was investigated. Maximum embryo dry weights were attained with vermiculite support, ovule perforation, and 10% sucrose in the medium. At high sucrose levels, all three tested media (Monnier, modified Murashige and Skoog, or modified Stewart and Hsu medium) performed similarly. Adding IAA and kinetin to culture media did not enhance embryo growth. Using the vermiculite support system, small embryos of early maturing peach cultivars, obtained at fruit maturity, were cultured successfully and used as maternal parents in breeding programs. Chemical name used: indole acetic acid (IAA).
M.A.R. Mian, R.M. Skirvin, M.A. Norton, and A.G. Otterbacher
To study the causes of low germinability in dried blackberry seeds, seeds harvested from fresh `Thornless Evergreen' (TE) blackberry (Rubus laciniatus Willd.) were either air-dried (12, 24, 36, 48, 60, 72, 96, or 120 hours) or explanted directly onto growth-regulator-free medium after bleach disinfestation. Seeds were either cut in half before explanting or kept intact. None of the intact seeds germinated. Fewer of the halved seeds dried 12 hours or more germinated than control (fresh moist) seeds (42.7% and 54.5%, respectively). Germination decreased to <12% following >48 hours of air-drying. In a separate study, fresh seeds of TE and `Navaho' were either dried as described or held in sealed petri dishes on moist filter paper (moist treatment) for up to 60 hours. After 60 hours, germination of dried seeds of both cultivars had decreased significantly; there was no significant change in germination percentage for moist seeds. Since moist halved seeds germinated well and dried halved seeds did not, the inability of dried blackberry seeds to germinate is due to more factors than just the hard seedcoat typical of the genus.
Arancha Arbeloa, Ma Elena Daorden, Elena García, Pilar Andreu, and Juan A. Marín
germination to embryo size in peach ( Chaparro and Sherman, 1994 ), apricot ( Burgos and Ledbetter, 1993 ), or interspecific peach hybrids ( Liu et al., 2007 ). Fruit breeding programs specifically use in vitro embryo culture because fruit tree breeding is a
Natalie Anderson, David H. Byrne, and Maria B. Raseira
A major obstacle faced by programs that breed early-ripening peach cultivars [Prunus persica (L.) Batsch] is the low viability of the embryos from the early-ripening parents that are used as females. Embryo culture techniques have been developed to allow embryos to mature in vitro, thus increasing the chances of germination and survivability. Several media types exist for Prunus embryo culture. Two types, Woody Plant Medium (WPM) and Smith, Bailey, and Hough (SBH) were investigated for this report. The WPM type was studied in two forms, one made from scratch and the other in a prepackaged form. The SBH type was studied with the addition of vitamins and without vitamins. Eight peach genotypes with embryo lengths ranging from 9.6 to 12.7 mm were used. Surprisingly enough, it was found that WPM from scratch performed better than WPM from a prepackaged mix. For all eight genotypes studied, WPM from scratch resulted in as good as or better germination than SBH with or without vitamins. A large media by genotype effect was found, which is partially attributed to the embryo size. The genotypes with larger embryos (>11 mm) tended to perform equally on all media tested whereas the embryos <10.5 mm germinated better on WPM as compared to SBH.
Paula P. Chee
An embryo culture method overcomes the lengthy dormancy requirement of Taxus L. spp. (yew) seeds. When zygotic embryos excised from mature T. brevifolia L. seeds were cultured in darkness for 4 weeks on one of three basal salt media (B5, Litvay, and Murashige and Skoog), radicle emergence and seedling development was highest on B5 basal salt medium. After 1 to 2 weeks on B5 basal salt medium, seedling development of T. brevifolia, T. cuspidata L., T. baccata L., and T. baccata stricta L. ranged from 2% to 36%. BA at 2.25 μm had no effect on radicle emergence; 22.5 μm prevented it. Embryos excised from mature or nearly mature seeds had the highest frequency of radicle emergence and seedling development. Cultured embryos developed seedlings in only 8 to 10 weeks. Chemical name used: N 6-benzyladenine (BA).