Developing elite lines and varieties requires breeders to combine traits from multiple parents and this process is called as gene pyramiding or stacking. Achieving this through conventional approach is time-consuming and often inefficient, requiring extensive phenotypic evaluation and relying on chance events for the accumulation of desired traits. Marker-assisted gene pyramiding offers a strategic alternative, integrating molecular markers with traditional breeding techniques3.

With the aid of marker assisted gene pyramiding breeders have introgressed multiple biotic and abiotic stress resistance/tolerance genes such as Pi9 gene for blast, Xa4, xa5, xa13 and Xa21 genes for Bacterial leaf blight, Bph3 and Bph17 genes for Brown plant hopper, Gm4, Gm8 genes for Gall midge and qDTY1.1 and qDTY3.1 QTLs for drought tolerance in a single cultivar of Rice (Swarna). This has enhanced the breeding efficiency and brought down the breeding time for multiple traits1.

Tomato is one of the leading and widely cultivated vegetable crops encountered by a number of diseases of which tomato leaf curl virus is the most devastating disease. Hence, a study conducted to stack four resistant genes (Ty-1/Ty-3, Ty-2, ty-5, and ty-6) into a commercial tomato hybrid JKTH811 using marker-assisted backcross breeding and genome recovery using ddRAD-seq revealed that the resulting parental lines and F1 hybrids exhibited significantly lower disease severity against Tomato leaf curl virus (ToLCV). Disease severity of Ty genes pyramided female lines and F1 hybrids were found as significantly lower when compared to original parental lines and hybrid2.

In conclusion, marker-assisted gene pyramiding represents a transformative approach to cultivar development. By harnessing the power of molecular markers, breeders can streamline the selection process, expedite trait accumulation, and create cultivars with enhanced performance and adaptability. This synergy between molecular genetics and traditional breeding methods paves the way for a more efficient and sustainable future in agriculture, benefiting farmers, consumers, and the global food system as a whole. 

REFERENCES 

1. DIXIT, S., SINGH, U. M., SINGH, A. K., ALAM, S., VENKATESHWARLU, C., NACHIMUTHU, V. V., YADAV, S., ABBAI, R., SELVARAJ, R., DEVI, M. N. AND RAMAYYA, P. J., 2020, Marker assisted forward breeding to combine multiple biotic-abiotic stress resistance/tolerance in rice. Rice., 13: 1-15.

 2. PRABHANDAKAVI, P., POGIRI, R., KUMAR, R., ACHARYA, S., CHAKRABORTY, M., PINNAMANENI, R. AND PALICHERLA, S. R., 2021, Pyramiding Ty-1/Ty-3, Ty-2, ty-5 and ty-6 genes into tomato hybrid to develop resistance against tomato leaf curl viruses and recurrent parent genome recovery by ddRAD sequencing method. Plant Biotechnol J., 30(3): 462-476.

3. YE, G. AND SMITH, K. F., 2008, Marker-assisted gene pyramiding for inbred line development: basic principles and practical guidelines. Int J Plant Breed., 2(1): 1-10.