New Concepts in Plant Breeding and Genetics

Abstract

Plant breeding is aimed at developing genetically improved crop cultivars with economic benefits for small-scale and commercial farmers. Plant breeders usually make crosses involving elite varieties and the modern cultivation practices of uniform high yielding varieties (HYVs) had reduced crop genetic diversity and predisposed crop plants to disease and insect pest epidemics. To counter these effects, plant breeder need to make deliberate efforts to diversify the gene pools of their crop to reduce genetic vulnerability. Also it is compulsory for breeder to look beyond the advanced germplasm pool to find desirable genes. The desired genes may reside in unadapted gene pools. But the transfer of genes from unadapted genetic resource often associates with linkage drag and unwanted characters. Hence these exotic germplasm often cannot be used directly in cultivar development. Instead the materials are gradually introduced into the cultivar development programme through crossing and selection for intermediate with new traits, while maintaining a great amount of the adapted traits.