ADAPTIVE PROPERTIES OF PICEA-ABIES PROGENIES ARE INFLUENCED BY ENVIRONMENTAL SIGNALS DURING SEXUAL REPRODUCTION

Several independent tests have shown that climate and weather during s exual reproduction influence the adaptive properties of the Picea abie s progenies. This phenomenon is expressed in seed orchards established by moving parent trees, propagated as grafts, from north to south, fr om high to low elevation, or from outdoor to indoor greenhouse conditi ons. The progenies exhibit delayed flushing in the spring, later growt h cessation of leader shoots in the summer, delayed bud-set, higher fr equency of lammas shoots and delayed development of frost hardiness in the autumn compared to progenies reproduced in the colder native envi ronment. The altered performance is during meiosis and pollen producti on. However, when crosses were made in early spring (March), inside a heated greenhouse (short day, high temperature), the progenies are les s frost hardy during cold acclimation than progenies from identical cr osses performed in late spring (May; long day high temperature) in the greenhouse. The most hardy offspring were from crosses performed unde r outdoor conditions in May (long day, low temperature). These results indicate that some stages in reproduction, such as female meiosis, po llen tube growth, syngamy and early embryo development, are sensitive to temperature and/or photoperiod which then alter the phenotypic perf ormance of the offspring. The most likely explanation is the existence of a regulatory mechanism affecting the expression of genes controlli ng adaptive traits. If this is true, it must have implications for the genetic interpretation of provenance differences in Norway spruce.