Development of codominant SCAR markers to detect the Pto , Tm2 2 , I3 and Sw5 genes in tomato ( Solanum lycopersicum )

• Published in: Plant breeding 2021-04, Vol.140 (2), p.342-348
• Main Authors: Zhang, Jianbo, Panthee, Dilip R.
• Format: Article
• Language: English
• ISSN: 0179-9541; 1439-0523
• DOI: 10.1111/pbr.12902

Marker‐assisted selection (MAS) can speed up the plant breeding process and reduce the labour and field costs. The sequence‐characterized amplified region (SCAR) marker allows the elimination of the restriction digestion step. Hence, it is more efficient and reliable than the cleaved amplified polymorphic sequence (CAPS) marker in gel‐based screening. But we still only have CAPS marker for many tomato disease resistance genes. By comparing the coding region and its flanking sequences of the disease‐resistant genes between the resistant and the susceptible varieties, we designed primers that can amplify fragments with different sizes from these varieties for the Pto , Tm2 2 , Sw5 and I3 genes conferring resistance to bacterial speck (BS), Tomato mosaic virus (ToMV), tomato spotted wilt virus (TSWV) and Fusarium wilt (FW) race 3, respectively in tomato. We tested these new markers using our tomato breeding lines and hybrids. All the new SCAR markers worked as expected. The fragments' sizes were amplified from the resistant variety, and the susceptible variety is 1,512 and 450 bp for Pto , 885 and 583 bp for Tm2 2 , 521 and 451 bp for Sw5 and 673 and 480 bp for I3 genes. All the new markers are tightly‐linked to the resistant genes; the markers of Pto , Tm2 2 , Sw5 and I3 are 3,306, 4,888, 0 and 8,310 bp from their corresponding coding sequences, respectively. These new markers may be useful for MAS in tomato breeding.