Cechy przyrostowe i jakościowe modrzewia polskiego [Larix decidua subsp. polonica (Racib.) Domin] z Góry Chełmowej w 37-letnim doświadczeniu rodowym

We have investigated among−family variation in growth and quality traits of Polish larch [Larix decidua subsp. polonica (Racib.) Domin] from Góra Chełmowa and Bliżyn. Growth traits were measured several times during the 37 years of growth in a progeny test in Kórnik (52 15’N and 17 04’E), while quality traits were investigated at age 22. We have found significant among−family variation in survival rate at age 15; DBH at age 15, 20, 22 and 37; and stand productivity at age 22. Family heritability was high for DBH (0.6−0.8), except after the thinning (0.41). For basal area it was increasing from about 0.4 at age 15 to about 0.7 at age 37. The larch population from Góra Chełmowa is distinguished by a characteristic deformation of a lower trunk (saber−shape). Such a deformation was also observed in this experiment with a high family heritability (0.83). Other quality traits – self−prunning, branch thickness and branch length – did not vary among families. In all traits, the larch family from Bliżyn was better−performing than families from Góra Chełmowa. However, a high variation among tested families and high values of heritability estimates lend possibility of selecting best parents that could potentially be crossed with other highly productive ones of better quality to transmit into progeny other favorable traits of larch from Góra Chełmowa – high resistance to abiotic stresses and low susceptibility to larch cancer. Value of such progeny should be tested in the future.