Pinus patula GENETIC PARAMETERS IN A PROGENY TEST AT TWO ALTITUDES

Abstract

In 2001, a Pinus patula Schiede ex Schltdl. et Cham improvement program was in Aquixtla, Puebla an improvement program with and aimed to increase bole volume and adaptation. In july 2005, a progeny test was established in two sites located at different elevation (S1 = 2660 m and S2 = 2980 m). Each trial included 84 half-sib families in an incomplete block design with 19 repetitions at random, with single tree plots. Plant height (HT), stem diameter at 30 cm (D030) and 1.3 m (DBH), whorls number (WN), volume (VOL) and survival were recorded. At 4 years, old only HT, D030 and NW were recorded, while at 5 years all traits were analized. Individual heritabilities (h²_i) in S1 for HT, D030 and NW at 4 years, and HT, D030, DBH, NW and VOL at 5 years were 0.16, 0.08, 0.18, 0.18, 0.09, 0.15, 0.16 and 0.16, respectively. Mean values for those variables were: 2.86 m, 5.62 cm, 8.2, 3.85 m, 7.44 cm, 4.53 cm, 10.8 and 4.43 dm³, respectively. Mean survival value in this study was 83 % (among families, 57 to 100 %), 1.1 % of trees appeared to be killed by cold (0 to 14.3 % among families). In S2 the h²_i found for the variables above mentioned and in the same order were 0.07, 0.04, 0.03, 0.13, 0.09, 0.12, 0.12, and 0.09; likewise, the means obtained for each variable were 1.45 m, 3.05 cm, 6.3, 2.19 m, 4.97 cm, 2.13 cm, 8.4 and 0.73 dm³, respectively. Average survival in S2 was 66 % (among families, 37.5 % to 100 %), 6.2 % of trees were killed by cold (0 to 26.7 %, among families).