Protocol optimization and assessment of genotypic response for inbred line development through doubled haploid production in maize

Harjot Kaur; Mohammed Kyum; Surinder Sandhu; Gagandeep Singh; Priti Sharma

doi:10.1186/s12870-023-04228-5

Protocol optimization and assessment of genotypic response for inbred line development through doubled haploid production in maize

BMC Plant Biol. 2023 Apr 26;23(1):219. doi: 10.1186/s12870-023-04228-5.

Authors

Harjot Kaur¹, Mohammed Kyum², Surinder Sandhu³, Gagandeep Singh¹, Priti Sharma⁴

Affiliations

¹ Maize Section, Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, Punjab, 141004, India.
² Department of Agronomy, University of Florida, Gainesville, FL, 32608, USA.
³ Maize Section, Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, Punjab, 141004, India. surindersandhu@pau.edu.
⁴ School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana, Punjab, 141004, India.

Abstract

Background: Doubled haploid technology offers the fastest route of inbred line development by rapidly fixing the desirable combinations in a single year. However, the differential response of haploid induction to genetic background of maternal lines accompanied with low induction rate and high mortality rate due to artificial chromosomal doubling of haploid seedlings creates hindrance in doubled haploid production on a commercial scale under tropical conditions. To speed up the hybrid breeding programme in sub-tropical maize, efforts are reported here to optimize the protocol for efficient production of fixed lines using haploid inducers. The second-generation haploid inducers i.e. CIM2GTAILs obtained from CIMMYT, Mexico were used for haploid induction in 13 F₁s of diverse backgrounds. For standardization of chromosomal doubling protocol, various concentrations of colchicine and two seedling growth stages were used to determine the extent of chromosomal doubling and survival rate of doubled haploid plants.

Results: A high mean haploid induction rate is obtained from CIM2GTAIL P2 (10%) as compared to CIM2GTAIL P1 (7.46%). Out of four treatments, CIMMYT reported protocol of chromosome doubling in tropical maize comprising combination of 0.07% colchicine and 0.1% DMSO at V₂ stage is highly effective for acquiring doubled haploid plants in sub-tropical adapted maize with high survival rate of 52.7%. However, increasing the colchicine concentration from 0.07 to 0.1% led to high mortality rate.

Conclusion: According to the findings, the haploid induction rate, survival rate and overall success rate varied depending upon the genotype of the inducer and the source population along with the concentrations of chemical used. The optimized protocol developed using CIMMYT haploid inducer CIM2GTAIL P2 for efficient doubled haploid production will not only fasten the breeding programme but will also reduce the production cost of doubled haploid with great efficiency in sub-tropical maize.

Keywords: Chromosomal doubling; Colchicine; Doubled haploid; Haploid induction rate; Sub-tropical maize.

MeSH terms

Chromosomes, Plant / genetics
Genotype
Haploidy
Plant Breeding* / methods
Zea mays* / genetics