Mutation breeding in Plants

Mutation Breeding a faster tool, yet environmentally friendly.

1. Presented By: Yogendra Katuwal AGR-O3 M, 2016 Department of Agronomy AFU, Rampur, Chitwan MUTATION BREEDING A faster tool, yet, Environmentally friendly

2. INTRODUCTION Mutation refers to sudden heritable change in the phenotype of an individual. Mutation may be the change in gene, chromosome or plasmagene (genetic material inside mitochondria and chloroplasts. Mutation occurs in two ways : By alteration in nuclear DNA ( point mutations) By change in cytoplasmic DNA(cytoplasmic mutation). The best example of useful cytoplasmic mutation is cytoplasm male sterility. The term mutation breeding (‘ Mutationszüchtung ’) was first coined by Freisleben and Lein (1944). He referred mutation breeding as the deliberate induction and development of mutant lines for crop improvement. Mutation breeding is a fundamental and highly successful tool in the global efforts of agriculture to feed an ever increasing and nutritionally demanding human population.

3. MILESTONES 1927 - First proof of induced mutations in plants; radium ray treatment of Datura stramonium ( Gager and Blakeslee). 1927 - Muller working with Drosphila provides proof of mutation induction by X-rays that induced mutation for animal and plant breeding and opens a new era in genetics and breeding. 1928 - Stadler in 1928 first used X-rays for induction of mutation in barley. 1936 - The first induced mutant variety was released, tobacco var. ‘ Chlorina ’ using X-rays in Indonesia. 1942 - First report of induced disease resistance in a crop plant; X-ray induced mildew resistance in barley ( Freisleben and Lein , 1942). 1944/46 First reports of chemical induced mutation (Auerbach and Robson, 1944). Father of mutation breeding - Ake Gustafsson .

4. TYPES OF MUTATION A. Spontaneous mutations: Mutation occur in natural populations . B. Induced mutations: Mutation may be artificially induced by various mutagenic agents. Induced mutations are of two types: 1. Macro-mutations: Mutation with distinct morphological changes in the phenotype. 2. Micro-mutations: Mutations with invisible phenotypic changes.

5. MUTATION BREEDING Inducing desirable mutations and exploiting them for crop improvement. Mutation breeding is commonly used to produce traits in crops such as larger seeds, new colors, or sweeter fruits, that either cannot be found in nature or have been lost during evolution.

6. PROCEDURES OF MUTATION BREEDING Choice of material : It should be the best variety available in crop and seed should be pure. Choice of mutagen : Depends upon the plant parts to be treated. Generally, chemical mutagens are more preferred for seed treatment and radiation for treatment of vegetative parts. Mutagenic treatment : In seed propagated species, generally, seed are treated. In vegetatively propagated species, buds, suckers or cuttings are used. LD50 is the dose of mutagen that kills 50% of the treated individuals. Duration of treatment depends on intensity of radiations or concentration of chemical mutagens. Optimum mutagen dose is one, which produces maximum frequency of mutations and causes the minimum killing. Handling of treated material : The handling of mutagen treated material differs in seed propagated species and vegetatively propagated species.

7. MUTAGENS Mutagen : Physical or chemical agent which greatly enhance the frequency of mutation. Mutant: Is an individual, organism, or new genetic character, arising or resulting from an instance of mutation. Types of mutagens: Physical mutagens: 1. Ionising radiation: Particulate radiations: alpha-rays , beta-rays, fast neurons and thermal neurons. Non-particulate radiations: x-rays and gamma rays. 2. Non- ionising radiation: ultraviolet radiation.

8. MUTAGENS B. Chemical mutagens: Alkylating agents: C ause mutation by adding alkyl group at various positions in DNA. Eg : EMS (ethyl methane sulphonate ), methyl methane sulphonate (MMS), sulphur mustard, nitrogen mustard Acridine dyes: They are very effective mutagens. Leads to addition or deletion and cause frame-shift mutations. Eg : P roflavin , acridine orange, acridine yellow Base Analogues: Chemical compounds similar to DNA bases. Eg : 5 Bromo Uracil, 5-chlorouracil. Other mutagens: Nitrous Acid, Sodium Azide .

9. Genetic structure changes: Gene (point mutation) Change in specific sequence of nucleotides in DNA molecules leading to formation of a new type of protein or preventing that of the normally protein Chromosomal mutation: Deletion or deficiency (loss of a chromosomal segment), Duplication (doubling of a chromosomal segment), Inversion (rearrangement of a group of genes in a chromosomal segment in a such a way that their order is reversed) and Translocation (change in position of a chromosome or exchange of chromosome segments) Genome mutation: Changes in sets of chromosomes.

10. HANDLING OF SEGGREGATING POPULATION M1 GENERATION Seeds treated with chemical mutagens should be washed thoroughly and be planted as soon as possible. Large M1 generation is raised from treated seeds (Wider spacing). E.g : 25,000 plants are to be grown to obtain a useful mutation in M1 generation. Mutagens if has high mutation frequency, then M1 generation size can be reduced. The M1 plants should not be allowed to cross pollinate. Dominant mutations are selected and each plants are selfed and harvested separately for M2 M2 GENERATION Two methods of sowing M2 generation can be followed M1 plant to row where all seeds produced from a single plant are grown in row M1 spike or branch to row

11. SCREENING/SELECTION Mainly three types screening/selection techniques are used in M2 and subsequent generation. 1. Visual: Most effective and efficient method for identifying mutant phenotypes. 2. Mechanical/Physical: Very efficient for seed size, shape, weight, density, etc. using appropriate sieving machinery. 3. Other methods: Low alkaloid content mutants can be selected using colorimetric tests. Chromatographic or electrophoresis techniques may be used to select isolate protein variants

12. ADVANTAGES OF MUTATION BREEDING Mutation breeding is a cheap and rapid method of developing new varieties. Induction of desirable mutant allele, which is not present in germplasm . Induced mutagens is used for the induction of CMS. Ethidium bromide (EB) has been used for induction of CMS in barley. Mutation breeding is more effective for the improvement of oligogenic characters. Production of haploids by irradiating pollens. Mutation breeding is the simple, quick and the best way when a new character is to be induced.

13. More than 3,200 mutant varieties including numerous crops (75 %), ornamentals and trees (25 %) have officially been released for commercial use in more than 210 plant species from over 70 countries (Source: FAO/IAEA Mutant Varieties Database ). PERCENTAGE OF MUTANT VARIETIES BY CROP TYPE

14. GLOBAL DISTRIBUTION OF MUTANT VARIETIES

15. HIGHLIGHTS OF SOME GLOBAL MUTANT VARIETIES 1 GENETIC ENHANCEMENT OF RICE The impact of induced rice mutants in applied research is best exemplified by the development of improved rice varieties through mutation breeding. During the past five decades, more than 800 varieties of rice have been developed across the globe, either directly from induced mutations or as a result of crossing such mutants with other breeding lines. The first rice varieties KT 20-74 and SH 30-21, developed through induced mutation, were released in China in 1957 Afterwards, the semi dwarf mutant Reimei was released in Japan which have significantly increased yield because of their lodging resistance. Calrose 76 and Basmati 370, semi dwarf varieties of rice with short and stiff straw has revolutionized the rice production in USA and Pakistan respectively.

16. contd 2 DEVELOPING DROUGHT AND SALINITY TOLERANCE IN WHEAT CROP ‘ Sharbati Sonora’, a semi dwarf and non-lodging mutant variety has made a significant contribution to wheat production in India. ‘ Sharbati Sonora’ was produced from red grained Mexican variety ‘ Sonara 60’ by gamma irradiation at the IARI, New Delhi, India. A high yielding mutant Stadler, developed in Missouri, USA had resistance to leaf rust and loose smut, better lodging resistance and early maturity. In Italy Durum wheat cultivation area was significantly expanded due to the cold tolerant mutant varieties.

17. contd 3 Enhancing lodging resistance in Barley crop Mutation breeding has been very successfully used in breeding barley, the introduction of ‘Diamant’ and ‘Golden Promise’ a gamma-ray induced semi-dwarf mutant revolutionized brewing industry in Europe. ‘Luther’, gamma ray induced mutant had 20% increased yield, higher tillering and lodging resistance and ‘ Pennrad ’, had winter hardiness, better lodging resistance and early ripening [46]. 4 Developing early maturing varieties of Peanut 5 High yielding and wilt disease resistant chickpea mutants 6 Improvement in Ornamental plants 7 Major economic successes in USA (rice, barley, sunflower, grape fruit), Pakistan (cotton), India ( blackgram ), Australia & Canada (linseed), Japan (pear), China (rice)

18. LIMITATIONS The process is generally random and unpredictable. Useful mutants are rare and predominantly recessive. Mutants can have strong negative pleiotropic effects on other traits. Health risks: handling, chemical mutagens; radiations, fast neutrons treatments. Most mutants are of no use to breeding even if a large number of mutants can be produced. Field trialing and germplasm storage can be expensive and require a lot of space and careful management if large mutant populations are handled.

19. CONCLUSION Applied since the 1930s to accelerate the process of developing and selecting new valuable agronomic traits, mutation breeding uses a plant’s own genetic make-up, mimicking the natural process of spontaneous mutation. The mutation process generates random genetic variations, resulting in mutant plants with new and useful traits. Mutation breeding is built on mutation induction and mutation detection. It has many comparative advantages: it is cost effective, quick, proven and robust. It is also transferrable, ubiquitously applicable, non-hazardous and environmentally friendly. Crop varieties generated through the exploitations of mutation breeding are significantly contributing to global food and nutritional security and improved livelihoods.

20. THANK YOU