GROWTH AND CROWN VIGOR OF 25-YEAR-OLD SHORTLEAF PINE PROGENIES ON A LITTLELEAF DISEASE SITE

Control-pollinated progenies of shortleaf pines that appeared to be re sistant to littleleaf disease were planted on a test site near Union, SC, in 1965. The planting was assessed at ages 17 and 25 to identify p rogenies with superior growth and resistance to pest problems associat ed with littleleaf disease sites. Among the 30 progenies in the experi ment, 2 produced more than 12 cubic feet of total volume growth per tr ee and an additional 5 produced more than 11 cubic feet per tree. Howe ver, at age 25 even the best growing progeny had individual trees with visual crown symptoms of littleleaf disease. A control seedlot from o pen-pollinated shortleaf pines ranked low in performance (7 ft(3)/tree ) and crown vigor. All trees with crown densities of less than 50 perc ent, regardless of parents, were growing poorly and in accelerated dec line. There was a close relationship between rankings in volume growth at ages 17 and 35, indicating that candidates for future tree improve ment programs can be reliably selected at an early age.