Shoot apex culture of dormant buds in chestnut

Abstract

Chestnuts (Castanea spp.) can be propagated by tissue culture methods such as meristem tip culture, shoot tip culture and bud culture. However, some limiting factors prevent using these methods extensively. For example, the explant collection periods of these methods are short, and the collection time is critical. In addition, shoot formation ratios of explants on the initial media and survival of these shootlets thereafter are generally low due to factors such as infection, browning, and vitrification. In this study the shoot apex of the dormant buds were used as the explants source for the first time. By use of this method the explant collection period was much longer and the mass multiplication probability increased. Three chestnut cultivars native to Turkey - 'Sariaslama', 'Osmanoglu' and 'Haciomer' Castanea sativa Mill. - were used in the study in two years of experiments 2007 and 2008. Two main media were used as initial to obtain shootlets: MS (1/2xNH(4)NO(3) and KNO3) and DKW (Driver-Kuniyuki walnut medium). In multiplication step MS (1/2xNH(4)NO(3) medium was used with 0.5, 1.0, 1.5 mg/L BAP concentrations and in rooting MS (1/2xNH(4)NO(3) with 1.0 and 2.0 mg/L IBA concentrations were used. Shootlet formation from the explants in 2008 was higher (66.66-95.45%) than in 2007 (42.00-75.00%). MS (1/2xNH(4)NO(3) and KNO3) medium has given successful results in this respect. Therefore it can be recommended as a growing medium. The multiplication coefficient varied between 3.12 to 3.57 in 2007 and 3.95 to 4.76 in 2008 according to the cultivars. Rooting of the shootlets was difficult, and no rooted shootlet was obtained. However the experiment is now being continued, and new rooting media will be tested. The results obtained from this study showed that this method can be efficiently used in the mass multiplication of chestnuts.