| Agronomic performance of randomly derived alloplasmic
wheats1 K.D. KOFOID and S.S. MAAN Dept. of Agronomy, North Dakota State University, Fargo, ND 58105, USA Utilizing alien cytoplasms has been suggested as a method to increase the genetic variability of wheat (Triticum aestivum L.) (1, 2). However, little work has been done to determine if lines can be extracted from segregating populations in an alien cytoplasm which equal or exceed the performance of lines extracted from segregating populations in normal wheat cytoplasm. BUSCH and MAAN (2) reported that some of the progeny of alloplasmic 'Chris' in Aegilops sqwarrosa L. cytoplasm exceeded the yield of euplasmic Chris, while none of the progeny of alloplasmic Chris in Ae. cylindrica Host., Ae. ventricosa Tausch, or Ae. juvenalis (Thell) Eig cytoplasm equalled the check. Their study was with nonsegregating genotypes and the expression of heterosis of segregating nuclear genes was not evaluated. The objectives of this study were to compare the agronomic performance of randomly derived lines from crosses involving euplasmic and alloplasmic parents and to determine if superior individuals could be obtained in an alien cytoplasm. Materials and Methods Two hard red spring wheat cultivars, 'Chris' and 'Selkirk', were used as male recurrent parents to substitute their nuclear genomes into the cytoplasm of Ae. squarrosa and Ae. bicornis (Forsk.) Jaub. & Spach. The alloplasmic lines thus produced were reciprocally crossed to Chris and Selkirk. The F1 was selfed and 20 F2 plants were randomly selected from each set of crosses. In addition, 20 plants were randomly selected from each of the euplasmic and alloplasmic parents. Each individual progeny was advanced as a bulk to the F8. The pedigree, cytoplasm source, and number of F2-derived F8 lines from each parent and cross are given in Table 1. The lines were tested in an incomplete block arrangment of a randomized complete block design with two replications at Fargo, ND in 1979. Each incomplete block consisted of all lines from any individual family. Each line was evaluated in two 2.4 m rows with 0.3 m between the rows. The traits measured on each line were: days to head, days from planting until 50% of the spikes had emerged from the flag leaf sheath; plant height, height from the ground to the tip of the spike in cm; grain yield, weight of the grain harvested from each plot converted to kg/ha ; and test weight, weight of a given volume of grain expressed as kg/hl. Results and Discussion All of the traits studied in the parents were affected by the Ae. bicornis cytoplasm (Table 2). The Ae. bicornis cytoplasm caused a significant delay in days to head with a significant decrease in plant height, grain yield, and test weight in both alloplasmic Chris (family 1 vs family 2) and Selkirk (family 6 vs family 7). The only significant effect of the Ae. squarrosa cytoplasm was a decrease in test weight of alloplasmic Chris (family 1 vs family 3). When the alloplasmic lines were crossed as male to the euplasmic lines, the mean performance of the progeny indicated that the deleterious effects of the alien cytoplasm were not transmitted to the progeny (family 2 vs family 4 , and family 7 vs family 9). Thus, the deleterious effects observed in the alloplasmic lines with the Ae. bicornis cytoplasm were caused by the Ae. bicornis cytoplasm. The yield level of the euplasmic lines derived from crosses of euplasmic controls by alloplasmic parents equalled the euplasmic controls, (families 4 and 5 vs 1 , and families 9 and 10 vs 6) and in the case of crosses involving alloplasmic Chris, the derived euplasmic progeny exceeded the control, although not significantly. |
| 1) Published with the approval of the Director, N.D. Agric. Exp. Stn. as Journal Article No.1072 |
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