Success Stories in MAS

Abstract

There is a tremendous amount of publications reporting the identification of new QTLs in crop plants since its first description in tomato during 1988. However, reports on the successful application of MAS in plant breeding programs are still limited. This fact is discussed in several papers and reviewed the current status and applications of molecular markers in public and private sector breeding programs (see further readings). Most of the critical reviewers have come to the conclusion that rate, scale and scope of uptake of genomics and MAS in crop breeding programs continually lag behind expectations. Thus, it has been repeatedly stated that the vast majority of the favourable alleles at these identified QTL reside in publications rather than in cultivars that have been improved through the introgression or selection of such QTLs. However, the aim of this book is to show the successful detection of QTLs by circumventing all the challenges that limit the transfer of knowledge from QTL mapping to routine MAS in plant breeding program. The previous chapters have addressed those approaches, and this chapter describes how those approaches have successfully applied in development of new crop cultivars. Critical analysis of published reports brought an impression that MAS has great potentials in genetic improvement of crop plants, if the limitations are properly looked for. Among the different MAS-based breeding strategies applied (refer chapter x), MABC/introgression is the main strategy that has been used in most of the publications. Regarding the breeding objective, breeding for disease/pest resistance is clearly dominating among publications since they are mainly controlled by major genes and detection of such QTLs is more or less accurate. However, few studies reported the successful application of MAS for improved yield, quality traits, abiotic stress tolerance, variety detection or growth character (see below). Another important fact among MAS studies is that the main marker technologies applied are predominantly microsatellite markers. Though almost all the publications are results from public breeding programs, it would be incorrect to conclude that MAS is mainly conducted in public breeding programs. What has to be considered is that publishing is of little or no importance for private plant breeders, while it is one of the main aims in public research institutes and at universities. The following section provides success stories made in different crops that employed MAS, and the list is not exhaustive. Due to space constraints, only few examples in each crop have been shown, merely to showcase that MAS has been widely employed in crop plants for their genetic improvement. Please refer the further readings to get more examples.