One should note that the techniques for breeding rust resistant cultivars or varieties with wheat are from a starting point involving transgenesis or rec-DNA technology and that despite gaining popularity there is always the question made of biosafety from an environmental and consumer standpoint.
Plse. refer to ref.: S. Savadi et al. 2018. Molecular breeding technologies and strategies for rust resistance in wheat (Triticum aestivum) for sustained food security. Plant Pathology 67(4): 771-791.
The most well-known technique for non-GMO breeding of plant crops is marker-assisted selection (MAS) using high-throughput bioinformatics and genomics which has been used with recent wheat rust race Ug99.
The following techniques outlined are of both varieties mentioned above (viz. molecular and breeding):
(a) cisgenesis=transgenesis of a gene that is commercially bred under conventional circumstances; either for same spp. or cross-species.
(b) intragenesis=like the above, but instead involving a DNA fragment.
(c) RNA-dependent DNA methylation (RdDM) which shows a lot of promise with methylation involving plant resistance (a complicated mechanism) to pathogens and can be exploited or manipulated for future breeding purposes for disease resistance in common wheat cultivars.
(d) agroinfiltration=basically involves use of vacuum applied to a liquid culture of cells using A. tumefaciens and transfer of T-DNA with protein expression of the desired gene transiently but with speed and convenience and higher and more consistent protein titre; in other words it is a useful molecular technique for transgenic approach or a study involving it.
(e) reverse breeding=finally, a technique to construct a double haploid from starting plants made haploid for alleles that is dominant for the desired trait such as, for e. g., resistance specifically against wheat rust race Ug99.
We will return again to this discussion on the possible technological horizon for bio-hubbing using feedstock from wheat fibre, viz. high-density alcohols and what is referred to as 'invert' wheat flour from fibre.