Review Paper on Approaches in Developing Inbred Lines in Cross-Pollinated Crops

Abstract

Plant breeding aims to constantly develop crop cultivars with improved yields and quality and tolerant to droughts, diseases and pests. Use of genetically improved crop cultivars and better management practices are among the best strategies to increase food production and meet a projected doubling of food demand. Inbred lines are homozygous genotypes produced by repeated selfing with selection over several generations. It is developed and maintained by repeated selfing of selected plants. In cross-pollinated species with strongly expressed self-incompatibility, various techniques are used to overcome the incompatibility. The technique of doubled haploids may be used to produce complete homozygous diploid lines in just 1 year (versus more than 4 years in conventional breeding) by doubling the chromosome complement of haploid cells. Doubled haploidy is and will continue to be a very efficient tool for the production of completely homozygous lines from heterozygous donor plants in a single step. Haploids contain half the chromosome number of somatic cells. Anthers/stigma Contain immature microspores or pollen grains with the haploid (n) chromosome number. If successfully cultured (anther culture), the plantlets resulting will have a haploid genotype. To have maximum genetic variability in the plantlets, breeders usually use anthers from F1 or F2 plants. Usually, the haploid plant is not the goal of anther culture. Rather, the plantlets are diplodized (to produce diploid plants) by using colchicine for chromosome doubling. This strategy yields a highly inbred line that is homozygous at all loci, after just one generation.