Synthetic hexaploids and its utilization in crop improvement

 

 

 Synthetic hexaploid (SH) are widely exploited in wheat wheat (AABBDD), it is developed by artificially generating a fertile hybrid between tetraploid durum wheat (Triticum turgidum, AABB) and diploid wild goat grass (Aegilops tauschii, DD).Wheat is an important staple food for 35% of world population and enormously grown cereal of the world. Efforts are being made to increase wheat productivity and a remarkable success named "Green Revolution" boosted the wheat productivity in 1960s. Synthetic cultivars proved to be a great source of unexplored genetic variability and possess an improved trait like high yield, tolerance to abiotic and biotic stresses, etc. The abundant genetic diversity in Synthetic Hexaploid Wheat(SHW) and triticale can effectively make breakthroughs in wheat genetic improvement through the inclusion of increased variation 1.

The source of elite genes for hexaploid wheat improvement are triticale, durum wheat cultivated diploid rye. Synthetic Backcross derived Lines (SBLs) are developed by crossing to an adapted local bread varieties), these show enhanced yield across the diverse range of environments, demonstrating their potential for improving wheat productivity worldwide. This is particularly an evident in moisture limited environments. The use of SBLs, advanced backcross QTL analysis, chromosome introgression lines, and whole genome association mapping is contributing to the elucidation of the genetic architecture of some of the traits 2. The production of Secondary Hexaploid Recombinants (SHR) from the crosses between octoploid and hexaploid triticale had become a widely used method in triticale improvement. Jan et al. (2017) conducted an experiment to examine salinity tolerance in SHW as compared to three commercial wheat varieties (Zarghoon-79, Kharchia and Shorawaki). All genotypes were grown at various salinity levels (0 mM, 50 mM, 100 mM, 150 mM and 200 mM) and then screened out for different parameters. They identified synthetic lines (genotypes 1 to 10) showed a significant tolerance to different levels of salt (Sodium Chloride; NaCl) as compared to commercial wheat cultivars. Two synthetic lines; genotypes 2 and 4 performed the best under stress condition. Synthetics produces new genetic variation for a range of biotic, abiotic, and quality-related traits. Synthetic derivatives, developed by crossing synthetics with adapted cultivars, have enhanced resistance to biotic and abiotic stresses. Thus combining novel genetic diversity in synthetics with that existing in the wheat gene pool can be expected to significantly enhance the adaptation and marketability of wheat and Triticale.

REFERENCES:

1. LI J., WAN, H.S., YANG, W.Y., WANG, Q., ZHU, X.G., HU, X.R., WEI, H.T.,TANG, Y.L., LI, C.S., PENG, Z.S. AND ZHOU, Y. H.,2014. Dissection ofgenetic components in a new high‐yield wheat cultivarChuanmai 104. Scientia. Agricultura.Sinica. 47: 2281–2291.(in Chinese)

2. MUJEEB-KAZI, A., KAZI, A.G., DUNDAS, I., RASHEED, A., CHEN, P., KISHI, M., BONNETT, D., WANG, R.R.C., BUX, H.,FARRAKH, S., 2013. Genetic diversity for wheat improvement as a conduit for food security. In:Donald Sparks (eds) Advances in Agronomy (in press) 3. JAN, S.U., JAMIL, M., ALIPOUR, H., BHATTI, M.F. AND GUL, A., 2017. Analysis of salinity tolerance potential in synthetic hexaploid wheat. Pak. J. Bot., 49 (4): 1269-1278.