ABSTRACT
This chapter discusses theory and approaches used to develop fertile doubled haploid plants from cytologically verified, gamete-derived haploid plants of tall fescue. Use of haploids and doubled haploids offers tremendous promise for more rapid genetic improvement of wind-pollinated, highly self-infertile grass plants such as tall fescue. The plants that were regenerated from cytologically verified haploids of tall fescue included some with 21, some with 42, and a few with 84 chromosomes. The three ploidies from a given haploid "parent" plant were useful in evaluation of ploidy effects on various forage characteristics. In progressive order, the evaluations consisted of visual examination of the newly regenerated plantlets; cytological examination of shoot and root tips; exposure to various stress conditions in controlled environments; and field evaluation for plant form, winter survival, and fertility. Visual examinations were continued as the plants progressed through the various stages of regeneration, rooting, early growth, and field evaluation.
