a) Haploids are used to study the chromosome behavior during meiosis. Study of chromosome pairing in mono-haploids indicates the presence of duplications in the chromosomes.
b) Study of chromosome pairing in haploids indicates the origin of different species of a plant.
c) Information on the ancestry of species can be obtained through the study of homoeologous chromosome pairing in the haploids of different allopolyploid species.
d) In cross-pollinated species, haploidy is an effective method for selecting viable combinations of genes which are then used as inbreeds after chromosome doubling.
e) In cases of self-incompatibility, inbred lines are readily produced by doubling the chromosome number of haploids.
f) Haploid tissues can be maintained in vitro in undifferentiated condition and they provide a source of suspension of haploid cells. Like micro-organisms, these haploid cells of higher plants can also be used to carry out new genetic researches such as mutational studies at physiological levels and biochemical analyses..
g) New genotypes can be incorporated into alien cytoplasm through androgenetic haploidy (androgenetic haploids may be produced by semi gamy and disruption of egg nucleus by irradiation). This method enables the transfer of a new genotype into the cytoplasm possessing factors for male sterility.
h) Haploidy can be used in specific breeding schemes for dioecious plants, such as, Asparagus officinalis.
i) Through chromosome doubling in haploids, homozygous lines can be produced for various climatic regions in one laboratory.
j) Haploids may be used to produce translocation stocks and aneuploid stocks which are of cytogenetic importance and can be used in improvement of crop plants.