Alternative Backcross Methods for Introgression of Variability into Triticle via Interspecific Hybrids
1989
Barker, T. | Varughese, G. | Metzger, R.
In order to transfer genetic variability from bread wheat (Triticum aestivum L. em. Thell) to triticale (X Triticosecale Wittm.), interspecific hybrids are made and then backcrossed to triticale to recover desired phenotypes. The interspecific F₁'S are normally used as females in the backcrosses, but a high rate of aneuploidy is transmitted to the BC1 through the hybrid ovules. A study was conducted to evaluate backcrosses using the F₁ as female vs. the reciprocal crosses using triticale as female. Data from two sets of crosses were collected on number of seedset per spike, percent recovery of viable plants, percent recovery of 42-chromosome plants, mean seed yield per plant, and number of plants selected. Using the F₁ as male parent and triticale as the female resulted in 58.0 to 81.7% recovery of viable plants vs. 3.8 to 34.0% for the TCL-male backcrosses. The percentage recovery of 42-chromosome plants ranged from 31.9 to 35.6% from Frmale backcrosses vs. 0.3 to 18.6% from TCL-male backcrosses. However, the difference in number of seeds set per spike and the per-plant seed yield increase for F₁-male crosses were not statistically significant. The F₁-male mating system, which utilizes pollen screening (elimination of inviable gametes), appears permit recovery of more viable plants and a higher proportion of euploid triticales following a single backcross.
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