Submitted to: Acta Horticulturae
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/30/2005
Publication Date: 7/30/2006
Citation: Anderson, N., Byrne, D.H., Ramming, D.W. 2006. In ovule culture success as affected by sugar source and fruit storage duration for nectarine embryos. Acta Horticulturae. 713:89-92. Interpretive Summary: Peach and nectarine embryos from early ripening varieties are not developed enough at fruit maturity to survive stratification and germinate without dying or decaying. Embryo rescue methods have provided a way to grow plants from these early ripening varieties so they can be crossed with other early ripening varieties. Many times facilities are limited for culturing embryos. If the fruit could be stored and the embryos cultured at a later date, a larger number of embryos could be processed making the program more efficient. It was found that storage of very small embryos for three weeks before in ovule/embryo culture was detrimental to embryo growth and survival, making it impractical for breeding.
Technical Abstract: Green [Prunus persica (L.) Batsch] fruit from two nectarine varieties was collected and cultured within a week of harvest and then again three weeks later. Ovules with small immature embryos (1.5 to 2.4 mm in length) were extracted from the fruit and cultured on Stewart and Hsu Medium with 1% activated charcoal and a sugar source of either 6% sucrose, 6% fructose, or a combination of 3% sucrose and 3% fructose. These were grown in the dark at 25ºC for 4 weeks in ovule at which time the viable embryos were extracted and cultured on Woody Plant Media with 2% sucrose. After 10 weeks in a cold room at 4ºC, the embryos were removed and placed under lights at 18ºC. The plants were rated for their shoot and root growth after 2 weeks under the lights. There were no differences observed among the carbohydrate treatments in either top or root growth although in general the 6% sucrose and the 3% sucrose-3% fructose treatments had more or equal embryo growth and better survival than the 6% fructose treatment. The 3 week storage period had a large detrimental effect on both embryo growth and survival.