Gene pyramiding-a broad spectrum technique for developing durable stress resistance in crops.

Abstract

The development of molecular genetics and associated technology like MAS has led to the emergence of a new field in plant breeding-Gene pyramiding. Pyramiding entails stacking multiple genes leading to the simultaneous expression of more than one gene in a variety to develop durable resistance expression. Gene pyramiding is gaining considerable importance as it would improve the efficiency of plant breeding leading to the development of genetic stocks and precise development of broad spectrum resistance capabilities. The success of gene pyramiding depends upon several critical factors, including the number of genes to be transferred, the distance between the target genes and flanking markers, the number of genotype selected in each breeding generation, the nature of germplasm etc. Innovative tools such as DNA chips, micro arrays, SNPs are making rapid strides, aiming towards assessing the gene functions through genome wide experimental approaches. The power and efficiency of genotyping are expected to improve in the coming decades. The present review discusses the design parameters in a gene pyramiding scheme, potential application of gene pyramiding in crop plant improvement, and the prospect and challenges in integrating MAS based gene pyramiding with conventional plant breeding programmes.   Key words: Gene pyramiding, marker-assisted selection, durable resistance