Articles containing the keyword 'grafting'

Seed production of micropropagated plants, seedlings and grafts of Silver birch (Betula pendula Roth) in a polyethylene greenhouse experiment was followed for five years. The grafts started flowering and seed production at the age of two years, one year earlier than other two types of material. At the age of three the seed production of both micropropagated plants and seedlings was already more than two times higher than that of the grafts. Variation between the clones was high and plant type x clone interaction was significant. At the age of four, in 1993, seed production was high in all three types of material. Seed production of the micropropagated plants was two times higher than that of the grafts but about 75% of that of the seedlings. In 1994 seed production of all three plant types was very low, which shows large variation between different years. The early development of the plant material types suggests that micropropagated plants have higher seed production than grafts and could well be used instead of grafts in polythene greenhouse seed orchards.

• Viherä-Aarnio, E-mail: av@mm.unknown
• Ryynänen, E-mail: lr@mm.unknown

In two separate studies, seedlings from 20 loblolly pine (Pinus taeda L.) families and Virginian pine (Pinus virginiana Mill.) were used as root stocks for grafting loblolly pine seed orchard clones. The rootstocks were open-pollinated seedlings from orchard clones chosen to represent a wide range of flowering and survival capabilities, based on their performance in a first-generation seed orchard. Scions were derived from the same 20 loblolly clones. The effects of scion clone were significant and large for nearly all measured traits. Rootstock significantly affected survival, growth, flowering and foliar nutrients of the grafted ramets. Neither survival nor growth of the crafts was related to survival of growth of the orchard clones from which their rootstocks were derived, however. Survival of incompatible clones was enhanced by grafting on genetically related rootstocks.

The PDF includes an abstract in Finnish.

• Schmidtling, E-mail: rs@mm.unknown

The mating system was analysed in the upper and lower crown of two groups of European larch (Larix decidua Mill.) clones divided according to the percentage of full seeds in the upper and lower crown parts. The overall multilocus estimate of outcrossing rate (t) was calculated to be 0.929. The differences of outcrossing rates between crown levels and clonal groups respectively were not statistically significant. The t estimates were greater for the upper crown level and for clones with higher percentage of full seeds in the upper crown level. However, among all observations there was no correlation between outcrossing rates and percentages of full seeds for particular crown levels and groups of clones. Observed similarity of outcrossing among grafts of the same clones may indicate genetic control of self-fertilization rate in individual European larch. 

The PDF includes an abstract in Finnish.

• Burczyk, E-mail: jb@mm.unknown
• Kosiński, E-mail: gk@mm.unknown
• Lewandowski, E-mail: al@mm.unknown