Application of marker-assisted selection for ahFAD2A and ahFAD2B genes governing the high-oleic acid trait in South African groundnut cultivars (Arachis hypogaea L.)

摘要

One of the major shortcomings in cultivated groundnut in South Africa is the short shelf-life of the product due to rancidity of the oil rich seeds. Polyunsaturated fatty acids are more susceptible to oxidation than mono-unsaturated residues. Thus, it would be preferable to adjust the oleic acid: linoleic acid ratio to a more favourable one. The high-oleic acid trait in groundnut was reported to be dependent on two homeologous oleoyl-PC desaturase genes,?ahFAD2A?and?ahFAD2B. Breeding of new cultivars with this characteristic can be time-consuming and expensive when doing fatty acid analysis in every generation for selection of the progeny with the highest oleic acid: linoleic acid ratio. Marker-assisted selection was applied to the local groundnut breeding program with the utilization of Real-Time PCR. The inheritance of the high oleic trait was followed in the 4th?backcross progeny and revealed that all combinations of the two genes were found, except the?ol2ol2?homologous mutant. The highest oleic acid percentage was found in progeny with all four mutant alleles (ol1ol1ol2ol2).