About the Project

Phase II (2019-2024)

The HTMA Phase II initiated from 2019 to 2023, and one year no cost extension upto  The second phase of the “Heat stress tolerant maize for South Asia through public-private partnership” (HTMA-II) will further strengthen the existing partnership between public and private institutions with required technical expertise and complementary strengths. It will take forward the genomics knowledge generated on heat stress tolerance and will further validate and utilize the same in generating next generation maize varieties that are equipped to tolerate heat or heat plus drought in the Asian tropics. The accelerated deployment and scaling-out of the new climate-resilient hybrids with enhanced levels of stress tolerance will be made possible through the strong public-private partnerships established under HTMA-I, equipped with gender inclusive delivery and benefit sharing, which will be further strengthened in HTMA-II through partnerships with International maize improvement consortium for Asia (IMIC-Asia), an alliance with Asian seed companies, led by CIMMYT.

The elite stress tolerant maize germplasm base developed through HTMA-II will help strengthen the breeding programs of the national partners in Bangladesh, India, Nepal and Pakistan, besides SME seed company partners, for sustained development and deployment of improved maize varieties in the stress prone agro-ecologies of South Asia beyond the project duration. Through capacity strengthening, the project also aims to generate a new breed of professionals that are better equipped in terms of technically as well as socially solid maize technologies for South Asia.

The major deliverables of the HTMA-II project will be: a) precision phenotyping network established for heat and combined heat and drought stress with high throughput platform based on remote and/or proximal sensing; b) Genomic regions for heat stress tolerance validated and deployed in elite genetic materials from CIMMYT and/or willing partners; c) An integrated conventional and molecular marker-assisted breeding pipeline implemented for developing stress resilient maize germplasm in South Asia; d) Genetically enhanced maize germplasm with improved heat and combined heat and drought tolerance utilized in product pipelines of CIMMYT, NARS and seed company partners in South Asia; e) New wave of elite stress-resilient maize hybrids from CIMMYT formally licensed to public and private sector partners for large scale evaluation in their target geographies/markets, and selected best-bet hybrids released and commercialized; f) At least 2000 metric tons of certified/truthfully labelled seed of first generation heat tolerant maize hybrids produced and delivered by seed company partners to maize farmers in stress-prone ecologies of South Asia, benefitting approximately 0.2 million smallholder farm families or about 1.4 million people by 2020, and sex-disaggregated data collected on ultimate beneficiary by each deployment partner trained on gender-responsive product deployment strategy; g) At least 100 scientists/technicians/students, respecting gender balance in participation, from partner institutions in South Asia trained on precision phenotyping, gender-responsive research and development, breeding for stress tolerance, and application of modern breeding tools (GS and DH technology) for accelerated development of elite maize hybrids.

The project will be implemented by CIMMYT in collaboration with national maize programs of the four maize growing countries in South Asia (Bangladesh, India, Nepal, and Pakistan) and seed company partners, including one MNC (Pioneer-Asia) and 23 SME seed company partners from Bangladesh (5), India (14), Nepal (1), and Pakistan (2), which are actively involved in maize seed business in the region.

Phase-I

The impact of climate change on agricultural production will be greatest in the tropics and subtropics, with South Asia projected to be particularly vulnerable from multiple stresses and low adaptive capacity (IPCC, 2007; Rodell et al., 2009; Niyogi et al., 2010; ADB, 2009). Many climate modeling studies suggest that high day- and night-time temperatures will become more common in the future and may represent a tremendous environmental hurdle to global food production (Lobell et al., 2011; Stebbins, 2011; Cairns et al., 2012). Maize is particularly vulnerable to the reproductive stage heat stress (Cairns et al., 2012). A recent study showed that each degree day spent above 30°C reduced the final yield of maize by 1% under favorable growing conditions and 1.7% under drought stressed environments (Lobell et al., 2011b). Most of the tropical maize growing areas in South Asia are highly vulnerable to drought and high temperature stress. Spring maize is an important option for intensifying and diversifying cropping systems in South Asia, especially in the in the upper and middle Indo-Gangetic plains, but is prone to severe heat stress during flowering/early grain filling stages (Prasanna, 2011).

Systematic efforts to develop maize cultivars with high temperature tolerance have only recently been initiated. Initial experiments undertaken by the CIMMYT-Asia team to identify heat stress tolerant tropical maize lines among the elite, drought tolerant (DT) maize germplasm developed in Mexico, Asia and Africa revealed: (a) high vulnerability of most of the tropical maize germplasm, including commercial cultivars in South Asia, to reproductive stage heat stress; and (b) poor correlation between drought and heat tolerance, indicating that physiological mechanisms that contribute to heat stress tolerance in maize may be different from those that contribute to drought tolerance (Zaidi and Cairns, 2011; Cairns et al., 2012). However, CIMMYT-Purdue University collaborative studies in the last two years showed considerable genetic variation for the target trait, including identification of some highly promising Asia-adapted, tropical maize lines developed by CIMMYT with tolerance to high temperature.

Accelerated development and deployment of heat stress resilient maize varieties requires: (a) carefully undertaken field-based phenotyping in several relevant sites as well as under technically demanding managed-stress screens, both of which are often beyond the capacity of individual breeding programs; (b) an understanding of the genetic architecture of the target trait, coupled with application of modern molecular breeding tools, including genome-wide association studies (GWAS), genomic selection (GS), and doubled haploid (DH) technology for rapid development of improved products; and (c) effective partnerships with committed seed companies in the target regions for sustainable delivery of climate resilient cultivars.

The proposed outputs of the project are: (a) generation of knowledge about the genetic architecture of heat stress tolerance in tropical maize germplasm, including biomarkers and bioassays for heat tolerance for utilization in breeding strategies; (b) elite heat stress tolerant tropical donors with/without drought tolerance identified and shared with the public and private partners; (c) South Asia-adapted maize lines with enhanced levels of heat stress tolerance, coupled with other adaptive traits, developed using molecular marker-assisted breeding through GWAS and  Genomic selection GS; (c) best-bet heat stress-resilient maize hybrids with high yield and other adaptive traits for potential deployment by NARS and private seed partners; and (d) well-trained human resources in precision phenotyping and selection for heat stress tolerance, and (e) application of modern tools (GWAS, GS and DH technology) for accelerated development of abiotic stress resilient crop varieties.