Cone Set, Seed Yield, Seed Quality, and Early Seedling Development of S2 Generation Jack Pine

Self-pollinations were made on 29 S1 1 trees and S1 l x S1 -mix crosses were also made on 24 of these she S 1 trees. Open-pollinated progenies from seed on the S 1 trees were also analyzed. Eight of the S l self-pollinated trees and 6 of the S1 x S 1 -mix crosses had complete cone abortion. About 69% of the cones in the self-pollinated S1 trees and 58% of cones in the S1 l x S 1 -mix crosses aborted by the end of the first. year; by cone maturity abortion reached 75 and 69%, respectively. Number of filled seeds per cone varied between female parent genotypes and some cones had no filled seeds. The S l self-pollinations yielded less than half as many filled seeds per cone as the S1 l x S1 -mix crosses and S 1 open pollinations. Germination of filled seed was generally high regardless of degree of inbreeding. Inbreeding depression in seedling height of the S 2 progenies averaged 15% after 10 weeks. The results indicate that jack pine is largely self-compatible even in the second selfed generation. A strong correlation between S 2 and S 1 x S 1 -mix progenies in seedling height together with wide within and among progeny variation indicates that selection for growth in inbred lines will be possible for improvement breeding in jack pine.

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Author(s): Thomas D. Rudolph

Publication: Tree Improvement and Genetics - Central States Forest Tree Improvement Conference - 1976