This manual is an in-house publication intended for training purposes only and .... drought tolerance planting has to be done after cessation of the rainy season ...
INDIA- AFRICA FORUM SUMMIT III SHORT TERM TRAINING PROGRAMME 2018
“Genetic Improvement of Tropical Tuber Crops through Conventional and Biotechnological Approach” Sponsored by Ministry of External Affairs, East & Southern Africa Division, New Delhi
Training Manual 01-15 March 2018
ICAR-Central Tuber Crops Research Institute (Indian Council of Agricultural Research, Department of Agricultural Research & Education Ministry of Agriculture and Farmer’s welfare, Government of India, New Delhi) Sreekariyam, Thiruvananthapuram-695017, Kerala, India
Published by Dr. Archana Mukherjee Director ICAR-CTCRI
Organized by Dr. M.N.Sheela (Course Director) Dr. Asha K.I. (Course coordinator) Dr. Asha Devi A. (Course coordinator)
Compiled & Edited by Dr. M. N. Sheela (Course Director) Dr. Shirly Raichal Anil Dr. Krishna Radhika N. Dr. Senthilkumar K. M. Dr. Visalakshi Chandra C.
This manual is an in-house publication intended for training purposes only and is not for public circulation. Copyright© 2018 ICAR-CTCRI. All rights reserved. Reproduction and redistribution is prohibited without approval.
Breeding for Drought Tolerance in Cassava A. V. V. Koundinya, Scientist, Division of Crop Improvement, ICAR-CTCRI, Thiruvananthapuram Roots and tubers have so far been regarded as inferior and neglected food crops even in areas where they are staples. For several decades, studies have examined the problems and potentials of root/tuber crops production, but limited progress has been made in improving the productivity of most of these crops under drought conditions (Daryanto et al. 2016). Cassava (Manihot esculenta Crantz.) is one of the major tropical tuber crops grown across the tropical regions of the world starting from Southern America to South East Asia and Australia through the Sub-Saharan Africa. It is an important source of energy for the millions of people in the tropical and subtropical parts of the world (Yan et al. 2013). Climate change is an undeniable truth and its consequences are being experienced by us. Drought is one of the most important outgrowths of erratic rainfall and shift in monsoon patterns. Under changing climatic situations, Kerala is facing severe drought since past few years. All the districts in Kerala received a low amount of rainfall during Southwest monsoon ranging from 24% deficit in Ernakulam to 59% deficit in Wayanad in 2016 while Thiruvananthapuram had 34% deficit. In the last year up to 19th July (2017), Kerala experienced 24% deficit in SW monsoon rainfall. Thiruvananthapuram has received 26% less rainfall while Wayanad received 57% less rainfall akin to previous year (IMD 2017). Cassava survives under moisture stress conditions, but, at the cost of tuber yield. The drought tolerance in cassava has not been quantified and it appears to be more related to survival, not the yield (Daryanto et al. 2016). The critical period of irrigation in cassava is initial 3-4 months after planting (George et al. 2001; Laban et al. 2013). Moisture stress, during this period, leads to the death of the plants. In Uganda, 84.27% mortality due to early period drought stress was observed (Laban et al. 2013). In Kerala, planting of cassava begins with the onset of Southwest monsoons (May to July). But, the delay in planting due to the delay in monsoons followed by drought significantly reduce the crop yield up to 30% further affecting root bulking (George et al., 2001). Subsequently the cassava passes through a dry spell from December to March during which the mean annual rainfall is
