HAPLOIDS

Definition; haploids are saprophytes with gametophyte

chromosomes number and have been produced in a variety of plant species using a variety methods.

• Haploids could be produced following delayed pollination, irradiation of pollen ,temperature, shocks colchicines and distant hybridsasation the most imp methods currently being used include

a) Anther cultureb) Ovule culturec) Chromosome ellimination

• Anther and microspore culture production of haploids through culturing anthers

or microspores on artificial culture medium. this leads to the growth of microspores into sporophytes.

After the initial reports of successful production of haploids from anther culture in datura{Guha and maheshwari,1966-1967}

Haploids have been obtained through anther culture in more than 150 species belonging to more than 2 dozen families of angiospem {{{{{{{{{{{[[[[

Parameters for anther and microspore culture• Conditions of growth donor plant• Genotype of donor plant • Pretreatment• The developmental stage of anther\microspore• The culture medium and conditions during culture

growth.

Microspore culture

May preferred over anther culture even through the degree of success is low this callus microspore are first using the fallowing steps.

• Anther dissected as above ,taken in a sterile beaker contain liquid medium and are pressed with glass rod or syringe piston to microspores squeegee out.

• The suspension with anthers and microspores is filtered through a nylon sieve, which allows only the microspores topazes through.

• The filtrate is centrifuged thrice, for 5min each at 500-800rpm {the pellet resuspended in afresh medium each time};

• The microspores are inoculated on solid or in a liquid medium maintained at 25c 16\8hr photoperiod .the microspores may develop directly into embroils within 15 daddy or follow one of the several indirect paths to produced haploid plantlets.

Ovule culture haploids have also been produced from cultured female

gametophyte. Success in this connection gymnosperm like zamia ,ephedra and cycads.

Although initial attempts for the production of haploids from cultured ovules in angiosperm were unsuccessfully ,haploid could be obtained later fractured ovule in anew crop species ,like barley wheat and tobacco, with more efforts in future, haploids from ovule culture will be produced in a number of plant species.

chromosome elimination it has been observed that in many cases of

wide hybridization ,chromosome of the male parent are eliminated after fertilization during the development of embryo.

USE OF HAPLOIDS IN PLANT BREEDING among the different used of haploids their use

in crop improvement is considered to be the most significant and stands out as the most important reason for emphasis on haploids research. Some of the important crops , where haploid plants have been produced like coffee grape, peanut, clover, citrus, rapeseed, potato, pepper, sunflower.

• Use of haploids in species with disomic inheritance

• The