COMPARATIVE SEED YIELD PERFORMANCE OF HIGH-BY-HIGH AND LOW-BY-HIGH CROSSES IN FLAX

Successful identification of a desirable segregant depends partly on t he parents chosen to make the crosses. This experiment was conducted t o compare performance and genetic variability for seed yield, yield co mponents, agronomic traits and harvest index of lines derived from low -and high-yielding flax (Linum usilatissimum L.) crosses, and to ident ify important yield components for flax seed yield improvement. The li nes chosen as high yielding parents for this experiment were 'Linott' and 'Summit'; and the low yielding parents were 'Grant' and CI2395. Th e high-yielding lines produced significantly more seeds per boil and h ad a higher harvest index than the low-yielding lines. Evaluation of 1 61 F-2:6 lines from four crosses among these lines showed that the gre atest genetic variability, highest cross average, and highest F-6 line seed yield occurred in the low x high cross,'Grant' x 'Linott'. All l ow x high crosses exhibited higher genetic variances for seed yield th an the high x high crosses. The high x high cross 'Summit' x 'Linott' had low genetic variance for seed yield. Number of bells per area was determined by linear regression, path coefficient analysis, and stepwi se multiple regression analysis to be the most important component of seed yield. This study showed that hybridization of low and high-yield ing flax lines may be useful to increase genetic variability and obtai n high-yielding flax lines.