Site Loader
Rock Street, San Francisco

Being origin in tropical and subtropical regions, rice is more sensitive to cold stress than other cereal crops (da Cruz et al. 2013). More than 15 million hectares of rice crop worldwide suffer from considerable cold stress (Sthapit and Witcombe 1998) at one or more stages of crop growth (Zhang et al. 2014). Cold damage is very severe in high altitude and temperate regions. Winter rice in tropical and subtropical regions is also affected by moderate chilling damage at different developmental growth stages in rice. The chilling injury causes poor crop establishment in direct seeded crops and seedling mortality at early establishment of transplanted Boro rice (winter rice) in Bangladesh and in some parts of India and Nepal (Sthalpit 1992, Kabir et al. 2015). Worldwide crop loss due to low-temperature damage accounts for approximately $ 2 billion annually. In Korea, in 1980 and 1993, low temperatures seriously damaged the Korean rice crop, with grain yields dropping by 26% and 9.2%, respectively, compared with the national average yield (MOAF 1994). In Australia, once in four years, rice crop suffers from cold damage at the reproductive stage leading to spikelet sterility, which accounts for the loss of $23.2 million annually (Farrell et al. 2001). In Bangladesh, boro rice in the northern districts and northeaster haor areas are frequently affected by low temperature. Short duration rice in the hoar regions (a deep basin area, which remains submerged during the whole monsoon), which needs to be harvested before the onset of the flash flood in early April, often suffers from cold shock at booting to flowering stage. However, farmers often take risk of late growing of short duration varieties to avoid cold damage which results in many a times into inundation of ripening crop. In 2017, around 0.3 million hectares of rice crop was inundated at grain filling to maturity stage (Islam 2018) accounting for a loss of around $450 million. Assuming flash floods occur once in three years, annual crop loss in the haor areas would be $150 million. Since, Sub1A or other submergence tolerance gene does not work for submergence at ripening stage of rice, the only option, development and adoption of cold tolerant varieties could help farmers save their ripening rice crop from the flash flood. Recent advances in mapping QTLs, sequencing and identification of candidate genes show promise for the rapid development of locally adapted cold tolerant rice variety. Use of rapid generation advance (RGA) technology might expedite this process. Furthermore, use of GS in the breeding program together with forward breeding for few target loci might result into the rapid improvement of the whole breeding program to develop cultivars having durable tolerance to cold stress. Thus, crop loss due to cold damage could be minimized. It has been shown that the potential benefit from developing a variety that could withstand cold temperature 1°C below the current minimum threshold temperature for the existing varieties are US$ 79 per ha per year (Singh et al. 2005).

Post Author: admin


I'm Eric!

Would you like to get a custom essay? How about receiving a customized one?

Check it out