Genome-wide association study to identify genomic regions influencing spontaneous fertility in maize haploids

Genome-wide association study to identify genomic regions influencing spontaneous fertility in maize haploids

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Efficient production and use of doubled haploid lines can greatly accelerate genetic gains in maize breeding programs. One of the critical steps in standard doubled haploid line production is doubling the haploid genome using toxic and costly mitosis inhibiting chemicals to achieve fertility in haploids. Alternatively, fertility may be spontaneously restored by natural chromosomal doubling, although generally at a rate too low for practical applications in most germplasm. This is the first large-scale genome-wise association study to analyze spontaneous chromosome doubling in haploids derived from tropical maize inbred lines.

Induction crosses between tropicalized haploid inducers and 400 inbred lines were made, and the resulting haploid plants were assessed for haploid male fertility which refers to pollen production and haploid fertility which refers to seed production upon self-fertilization. A small number of genotypes were highly fertile and these fertility traits were highly heritable.

Agronomic traits like plant height, ear height and tassel branch number were positively correlated with fertility traits.

In contrast, haploid induction rate of the source germplasm and plant aspect were not correlated to fertility traits. Several genomic regions and candidate genes were identified that may control spontaneous fertility restoration.

Overall, the study revealed the presence of large variation for both haploid male fertility and haploid fertility which can be potentially exploited for improving the efficiency of doubled haploid derivation in tropical maize germplasm.

 

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Posted on , November 17, 2019

jbossuet

Agriculture expert and research-for-development communications specialist with 20 years international development experience including food and nutrition security projects in Africa and Asia. I work at the International Maize and Wheat Improvement Center (CIMMYT) in Nairobi to showcase the impact of maize and wheat science for better livelihoods in Africa. I am interested in any new solutions to key development challenges like fight against malnutrition, gender gap, how to scale sustainable intensification practices.
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