“Numerical Chromosomal Aberrations and Their Utility in Plant Breeding”

UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE

DEPARTMENT OF GENETICS AND PLANT BREEDING

M.Sc. Seminar - GPB 582 (0+1)

“Numerical Chromosomal Aberrations and Their Utility in Plant Breeding”

Numerical chromosomal aberrations, also known as aneuploidy, refer to changes in the number of chromosomes within a cell or organism, where there are either extra or missing chromosomes compared to the normal diploid number. These aberrations arise from errors during cell division, specifically when chromosomes fail to separate properly during meiosis or mitosis².

Aberrations are classified into aneuploids and euploids. Aneuploids involve either extra chromosomes (trisomy or tetrasomy) or missing chromosomes (monosomy or nullisomy). Euploids refer to changes in the whole set of chromosomes, including haploidy, triploidy, or tetraploidy. Depending on the type, aberrations show unique meiotic behaviour compared to their diploids and may form univalents, trivalents, or multivalents during meiosis, which are valuable tools in plant breeding. They can be leveraged to enhance desirable traits like increased yield, disease resistance, and tolerance to environmental stresses, along with the creation of new plant varieties and mapping of genes on chromosomes³.

Neo-tetraploid rice Huaduo 4 and Huaduo 5 lines exhibited a high number of genetic variations compared to their autotetraploid parents Jackson-4x (maternal, T45) and 96025 (paternal, T44), with notable levels of heterozygosity. The variation patterns showed active genomic differentiation in genes Os01g0719100, Os04g0572600, Os05g0392400, especially in comparison to the paternal parent (T44), and were experimentally validated¹.

Numerical chromosomal aberrations, such as aneuploidy and euploidy, offer significant potential for plant breeding, particularly in developing new crop varieties with enhanced traits and improved productivity. While challenges exist, advancements in technologies like CRISPR-Cas genome editing and high-throughput phenotyping are expanding the possibilities for utilizing chromosomal aberrations in plant breeding.

REFERENCES

1. Bei, X., Shahid, M.Q., Wu, J., Chen, Z., Wang, L. and Liu, X., 2019. Re-sequencing and transcriptome analysis reveal rich DNA variations and differential expressions of fertility-related genes in neo-tetraploid rice. PLoS One, 14(4): 0214953.

2. Gupta, P.K., 2016. Cytogenetics, 1st ed., pp. 109–252.

3. Sattler, M.C., Carvalho, C.R. and Clarindo, W.R., 2016. The polyploidy and its key role in plant breeding. Planta, 243: 281–296.