Marker assisted stacking of Ty3, Mi1.2 and Ph3 resistance alleles for leaf curl, root knot and late blight diseases in tomato

Developing multiple disease resistance through naturally available host resistance alleles is a challenging as well as rewarding area of research. Availability of host resistance alleles and the reliability of their identification through diagnostic molecular markers have paved the way for stacking of these resistance alleles for developing important genetic resources in tomato. Here we report the marker assisted stacking of Ty3, Mi1.2 and Ph3 alleles, governing leaf curl, root knot and late blight disease resistance, respectively, in superior F(4 )segregants of tomato derived from two diverse parents (i.e., BRDT-1 and H-88-78-1). Marker assisted selection was applied only on morphologically superior segregants at F-2 and F-3 generations, which helped us in identifying suitable lines even from a relatively small population. The diagnostic values of the employed molecular markers advocate that the identified superior segregants, carrying all the three aforementioned resistance alleles in homozygous condition, are suitable to be explored as valuable genetic resources for developing multiple disease resistance through rapid introgression of these genes in different genetic background of tomato. Identification of suitable segregants derived from these lines should be promising for obtaining improved cultivars in near future. Nevertheless, these lines might be further explored to decipher the intrinsic details of host's resistance mechanism involving genetic interactions between different resistance factors.

Automated summary

Developing multiple disease resistance in tomato through the stacking of naturally available host resistance alleles is a challenging yet rewarding area of research. In this study, we successfully applied marker assisted selection to identify superior segregants carrying three resistance alleles for leaf curl, root knot, and late blight disease, respectively. These segregants, derived from two diverse parents, have the potential to be valuable genetic resources for developing multiple disease resistance cultivars through rapid introgression of these genes.