गेहूँ सुधार के लिए डबल्ड हैप्लोइडी तकनीक: एक परिचय 

Doubled haploidy technique is used to generate pure inbred lines for basic research and production of commercial cultivars. These lines are pure and genetically homozygous individuals are produced when spontaneous or induced chromosome duplication of haploid cells occurs.

Double haploids are one of the biggest achievements in plant breeding because of production of completely homozygous plant within a year (Hooghvorst and Nogues., 2021).

The production of doubled haploid lines can accelerate the breeding of new wheat varieties by several years through one step creation of 100% homozygous plants. This technology plays an important role in studying the genetic control of traits in wheat, marker assisted selection, genomics and genetic engineering (Eliby et al., 2022).

Double haploid breeding is useful tool in wheat improvement by providing instant homozygosity, which leads to instant fixation of desirable characters of recombinants as well as reduction in number of generations required to achieve success.

Barclay (1975), initiated chromosome elimination technique in wheat, who recovered the wheat haploids in crosses between the wheat variety Chinese spring and Hordeum bulbosum.

The technique was genotype-specific due to the presence of dominant crossability inhibitor genes Kr1 and Kr2 genes thereby affecting the practical value of the technique. Therefore, wheat x maize system of doubled haploid production, which was genotypic non-specific was used by the researches for doubled haploidy induction in wheat.

Although the wheat × maize system of haploid production is quite successful yet maize crop needs to be grown in the greenhouse to coincide flowering with wheat which increases the haploid production cost.

Of the new, wheat x Imperata cylindrica has been discovered for DH production in wheat. The Imperata cylindrica (2n=20), performs better than maize and crosses with all wheat genotypes and is identified as efficient pollen source. Imperata cylindrica, also known as “Cogongrass” is a member of Gramineae family.

It is a winter season perennial grass which grows wild and is available in the surrounding of the wheat fields. There are some advantages of I. cylindrica in double haploid breeding(Patial et al., 2022; Chaudhary, 2008).

• Imperata cylindrica does not need to be grown in greenhouse as the maize grows and also no need to raising the pollen parent as it is perennial in nature.
• The frequency of haploid embryo formation and regeneration through this grass is higher than maize mediated system.
• cylindrica pollen is insensitive to crossability inhibitor genes therefore it is widely used for haploid plant production.
• The use of cylindrica in double haploid production is reported to be most economical and most efficient due to its genotypic non specificity, simplicity, efficacy, lack of somaclonal variation, time saving ability and low cost coupled with higher regeneration (Patial et al., 2016).

Sharma et al. (2019) reported a cross between triticale × wheat and wheat × rye hybrids. These recombinants were subjected to Imperata cylindrica- mediated chromosome elimination approach of double haploidy breeding. The variability in the haploid induction parameters was observed for the embryo formation and regeneration.

Kishore et al. (2011) conducted intergeneric hybridization in wheat-rye derived backcrosses to study the relative efficiency of maize and I. cylindrica chromosome elimination approaches in haploid plants induction.

The comparison of induction of haploid plants in wheat × rye backcross derivatives showed that the wheat × I. cylindrica was superior compare to the wheat × maize system.

Patial et al. (2017) used two spring and three winter wheat genotypes to develop F₁’s three-way F₁’s.  The wheat F₁’s and three way F₁’s were crossed with I. cylindrica, which resulted in efficient embryo formation (3.54% to 8.13%) and haploid plant regeneration (0 to 11.11%).

Patial et al. (2022a) reported the development of genetic stock for rust resistance in wheat via I. cylindrica-mediated double haploid technique. The developed wheat genetic stock “DH-1” was resistant to yellow and brown rust, has semi-spreading growth habits, erect flag leaf attitude, plant height of 94cm, have scurs and 1000 grain wheat of 36g.

Hence this shows that the production of doubled haploids by I. cylindrica mediated chromosome elimination technique is an effective tool for the development of wheat rust resistant lines in shortest timeframe (Patial et al., 2022b).

Double haploid technique is very efficient and successful tool to shortens the time period to release a variety. Double haploid lines have applications in basic and applied researches.

There are many unique advantages of double haploid breeding like it saves time, space and labour, small selection population sizes, elimination of deleterious mutations, useful in the development of transgenics, additional variation in the form of gametoclonal variations and elimination of dominant alleles controlling undesirable traits (Patial, 2016).

References

1. Barclay, I.R. (1975). High frequencies of haploid production in wheat (Triticum aestivum) by chromosome elimination. Nature, 256(5516), 410–411. https://doi.org/10.1038/256410a0
2. Hooghvorst, I., Nogues, S. (2021). Chromosome doubling methods in doubled haploid and haploid inducer-mediated genome-editing systems in major crops. Plant Cell Rep40, 255–270.
3. Eliby S., Bekkuzhina, S., Kishchenko, O., Iskakova, G., Kylyshbayeva, G., Jatayev, S., Soole, K., Langridge, P., Borisjuk, N., Shavrukov, Y. (2022). Developments and prospects for doubled haploid wheat. Biotechnology Advances 60,108007.
4. Chaudhary, H. (2008). Dynamics of wheat x Imperata cylindrica - a new chromosome elimination mediated system for efficient haploid induction in wheat.
5. Patial, M., Chaudhary, H.K., Sharma, N. et al.(2022a). Developing genetic stock for yellow and brown rust resistance in Triticum aestivum via Imperata cylindrica-mediated doubled haploidy technique. CEREAL RESEARCH COMMUNICATIONS 50, 439–448. https://doi.org/10.1007/s42976-021-00180-y
6. ­Patial M., Pal, D., Chaudhary H.K., Kumar J. and Thakur, A. (2016) Exploring the potential of Imperata Cylindrica, a Wild Grass for development of doubled haploids in wheat. International Journal of Tropical Agriculture Vol. 34, No. 5.
7. Patial, Chauhan R., Chaudhary, H.K., Pramanick,K.K., Shukla, A.K., Kumar V. and Verma, R.P.S. 2022b. Au-courant and novel technologies for efficient doubled haploid development in barley (Hordeum vulgare L.). https://doi.org/10.1080/07388551.2022.2050181
8. Kishore, N., Chaudhary, H.K., Chahota, R.K., Kumar, V., Sood, S.P., Jeberson, S. and Tayeng, T. (2011), Relative efficiency of the maize- and Imperata cylindrica-mediated chromosome elimination approaches for induction of haploids of wheat-rye derivatives. Plant Breeding, 130: 192-194.
9. Patial, M., Pal, D., Chaudhary, H. K., Kumar, J., & Prabhu, K. V. (2017). Exploration of wild grass Imperata cylindrica for development of doubled haploids in winter x spring wheat (Triticum aestivum) hybrids accompanied with combining ability and hybrid potential estimation. INDIAN JOURNAL OF GENETICS AND PLANT BREEDING, 77(02), 316–320. https://doi.org/10.5958/0975-6906.2017.00043.8
10. Sharma, P., Chaudhary, H.K., Manoj, N.V. et al.Haploid Induction in Triticale × Wheat and Wheat × Rye Derivatives Following Imperata cylindrica-Mediated Chromosome Elimination Approach. CEREAL RESEARCH COMMUNICATIONS 47, 701–713 (2019). https://doi.org/10.1556/0806.47.2019.46

Authors:

Tanvi Verma^a, Silky Gandhi^a, Santosh Kumar Bishnoi^b, Charan Singh^b, K.K. Pramanick^a, Dharam Pal^a, A.K. Shukla^a, Anjana Thakur ^c, Manoj Kumar^a and Madhu Patial^a*

^a ICAR-IARI, Regional Station, Tutikandi Centre, Shimla (H.P), India

^b ICAR-IIWBR, Karnal, India

^cCSK HPKV, Palampur, H.P

*Email: This email address is being protected from spambots. You need JavaScript enabled to view it.