Chromosome manipulations for crop improvement

Abstract

For numerous crops, a series of cytogenetic stocks have been prepared. These stocks were haploids, monosomic, trisomic, autotetraploids, extracted alloploids, synthetic alloploids, alien chromosome substitution, and alien chromosome addition lines. Before this, the groundwork of cytogenetics was laid, during 1900-1904, on the basis of parallelism recognized between the chromosomal theory of inheritance and Mendel's laws of inheritance. Molecular cytogenetic methods like, genomic in situ hybridization, fluorescence in situ hybridization (FISH), fiber-FISH, chromosome image analyzing system, chromosome banding, chromosome microdissection, chromosomal flow sorting, and plant artificial chromosomes (PACs). Cytogenetic stocks can be characterized cytologically and genetically. These stocks are being used for constructing comparative, physical, genetic, and molecular maps. Numerous breeding lines have been developed by haploid breeding and many varieties have been released. Many varieties have also been prepared using Autotetraploids. A variety of amphiploids and interspecific hybrids have also been produced. Great success has also been achieved in the development of alloploids by crossing polyploids or diploids with synthetic alloploids and manipulating the alien addition lines and alien substitution lines. With the help of different tools, useful genes have been transferred, for resistance against many diseases, abiotic stress, insect resistance, and improvement of gain quality, in oats, wheat, rice, cotton, Brassica, and many other horticulture plant species. Introgression for disease resistance has also been done.