engleski

Phenological differences in clonal seed orchards of non – infected narrow leaf ash (Fraxinus angustifolia Vahl) - monitoring Chalara fraxinea

In Croatia, narrow-leaved ash (Fraxinus angustifolia Vahl) is widely distributed in the Pannonian lowland area, along the rivers Sava, Drava and Danube. The greatest portion of its genetic variability is localized through Sava river region. In this area we have established two clonal seed orchards. First clonal seed orchard of narrow leaf ash (Nova Gradiška) was established in 2005 in the area of 3.5 ha with 56 clones. The grafts were planted with 4 × 4 m spacing. Second clonal seed orchard of narrow leaf ash (Čazma) was established in 2007 in the area of 7, 3 ha, and the grafts were planted with 5 × 5 m spacing and it contains 50 clones. Through the period of two years we observed the phenological differences in monitoring the six flushing phases on different clones with four repetitions, on wich we based our strategy to determine interclonal and intraclonal discrepancies and variations. Also the temperature and humidity was measured in the seed orchards and compared with the results of the flushing phases. In this period seed orchards where continuously monitored and checked for the presence of Chalara fraxinea, but it was not confirmed, and on the clones there were no simptoms that would indicate its presence. With the results gathered from this monitoring we where able to determine and classify clones into early and late flushing groups, which has a high practical value not only for seed orchard protection and maintaning the high vitality of the clones, but also for the distribution and application of seed from the seed orchard. Furthermore for some clones we have determined substantial intraclonal variations in flushing phases.

Narrow leaf ash (Fraxinus angustifolia); Chalara fraxinea; clonal seed orchards; phenological differences; flushing phases

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