|Graybosch, Robert - Bob|
Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/1/2003
Publication Date: 11/1/2003
Citation: Kumlay, A., Baenziger, P.S., Kill, K., Shelton, D.R., Graybosch, R.A., Lukaszewski, A., Wesenberg, D. 2003. Understanding the effect of rye chromatin in bread wheat. Crop Science. 43:1643-1651. Interpretive Summary: Wheat has a number of close relatives that may be used as a source of valuable genes for disease resistance and agronomic improvements. These genes may be introduced to wheat via the process of chromosome engineering, whereby pieces of chromosomes from related species are introduced to wheat, replacing pieces of wheat chromosomes. Among wheat¿s close relatives, rye has proven to be the most valuable. Fragments of rye chromosomes introduced to wheat have been used to improve grain yield, enhance resistance to drought stress, and to provide resistance to fungal and insect pests. Unfortunately, introductions of rye chromosomes often have the negative effect of reducing processing quality. This study was conducted to investigate whether placement of the rye chromosome introgression has an effect on agronomic performance and quality of the recipient wheat lines. The short arm of rye chromosome 1RS was introduced to wheat at three different positions, attached to the long arms of wheat chromosomes 1A, 1B and 1D. Attachment to 1A was found to be the least detrimental to wheat quality. Attachment to 1B was found to be the most advantageous for agronomic performance. Chromosome arm 1RL or rye also was introduced, but had no perceived agronomic advantages.
Technical Abstract: Many researchers have studied the effect of 1RS.1BL and 1RS.1AL translocations in wheat (Triticum aestivum L.), but they could not separate the effects of the introgression of the rye (Secale cereale L.) chromosome arm from the absence of a corresponding wheat chromosome arm. The objective of this research was to separate these effects by determining the agronomic and end-use quality effects of the individual wheat and rye group-1chromosome arms in wheat in various substitutions and translocations. Five group-1 ditelosomics, six 1R substitutions and 16 translocations of 1R in Pavon 76 wheat and their appropriate controls were studied. All ditelosomic lines of Pavon 76 were significantly different from Pavon 76 for 1000-kernel weight, flour protein, Mixograph peak time, Mixograph tolerance, and sodium dodecyl sulfate sedimentation volume. Among the long arms, 1DL was the most important for end-use quality and 1AL appeared to be the least important; the contribution of the short arms 1AS, 1BS or 1DS was low. All substitutions of complete 1R negatively impacted agronomic performance with the long arm being entirely responsible for this effect. Among translocation lines, that with 1RS.1BL had the highest average yield and 1RS.1DL the lowest. Negative impact of all translocations of 1RS to 1L arms on the end-use quality was greater than the impact of the absence of the corresponding 1S arms of wheat. This clearly demonstrates a negative contribution of 1RS to the reduction of quality of the translocations lines. Translocation 1RS.1AL appeared to be the least detrimental to quality and 1RS.1DL the most detrimental. The 1RL tested appeared to positively affect quality when replacing 1AL but it was unable to compensate for the absence of 1BL or 1DL. Both the sources of the rye chromatin and its position in the wheat genome appeared to affect agronomic performance and quality. These results suggest that it may be possible to create new translocations of 1RS in wheat with improved performance relative to the existing translocation lines. Of the three possible locations of 1RS, translocation to 1AL are preferred from the quality point of view; that to 1BL appears more beneficial for agronomic performance.