VARIATION IN REPRODUCTIVE TRAITS AND GERMINATION OF Pinus leiophylla Schiede ex Schltdl. & Cham.

Abstract

Variability in reproductive traits and seed germination in a seed orchard of Pinus leiophylla Schiede ex Schltdl. & Cham. was determined. The dried weight of each of 20 cones per tree was measured. The number of variables registered were: potential seeds, percentages of filled and empty seeds, percentage of abortive ovules, average weight per seed, inbreeding depression index and reproductive efficiency. Seeds were germinated on dumped cloth in plastic boxes set in a germination chamber. There were significant differences among trees for all included traits. The overall average of a dried cone weight was 15.2 g. The mean number of potential seeds per cone was 108. The percentage of abortive ovules was 63.7 % of the seed potential. Filled and empty seeds represented 17.7 % and 18.6 % of the seed potential, respectively. The average weight per seed was 11.6 mg (86 200 seeds per kg). The average inbreeding depression index (0.50) showed a high self-fertilization rate. The reproductive efficiency was 15.9 mg of seed per gram of cone. The germination capacity (82.5 %), peak value (8.5) and germination value (29.4) revealed a high seed quality. Trees contributed with 41.3, 29.3 and 36.9 % for germination capacity, peak value, and germination value, respectively, to the total variation, thus indicating high genetic variability for germination parameters and reproductive traits. In spite of the high inbreeding depression and the low number of filled seeds, the trees in the P. leiophylla orchard were able to produce sound seeds of high quality, according to germination results.