Grain yield, adaptation and progress in breeding for early-maturing and heat-tolerant wheat lines in South Asia

S Mondal,R.P Singh,E.R Mason,J Huerta-Espino,E Autrique,A.K Joshi

doi:10.1016/j.fcr.2016.04.017

S Mondal, R.P Singh + Show 4 more

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https://doi.org/10.1016/j.fcr.2016.04.017

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Abstract

Maintaining wheat productivity under the increasing temperatures in South Asia is a challenge. We focused on developing early maturing wheat lines as an adaptive mechanism in regions suffering from terminal heat stress and those areas that require wheat adapted to shorter cycles under continual high temperature stress. We evaluated the grain yield performance of early-maturing heat-tolerant germplasm developed by CIMMYT, Mexico at diverse locations in South Asia from 2009 to 2014 and estimated the breeding progress for high-yielding and early-maturing heat-tolerant germplasm in South Asia. Each year the trial comprised of 28 new entries, one CIMMYT check (Baj) and a local check variety. Locations were classified by mega environment (ME); ME1 being the temperate irrigated locations with terminal high temperature stress, and ME5 as hot, sub-tropical, irrigated locations. Grain yield (GY), days to heading (DTH) and plant height (PH) were recorded at each location. Effect of temperature on GY was observed in both ME1 and ME5. Across years, mean minimum temperatures in ME1 and mean maximum temperatures in ME5 during grain filling had significant negative association with GY. The ME1 locations were cooler that those in ME5 in the 5 years of evaluations and had a 1–2t/ha higher GY. A mean reduction of 20days for DTH and 20cm in PH was observed in ME5. Negative genetic correlations of −0.43 to −0.79 were observed between GY and DTH in South Asia during 2009–2014. Each year, we identified early-maturing germplasm with higher grain yield than the local checks. A positive trend was observed while estimating the breeding progress across five years for high-yielding early-maturing heat tolerant wheat compared to the local checks in South Asia. The results suggests the potential of the high-yielding early-maturing wheat lines developed at CIMMYT in improving wheat production and maintaining genetic gains in South Asia.

Highlights

Wheat, an important source of calories and proteins is a key cereal crop that impacts the global economy and food security
The Cereal Systems Initiative in South Asia (CSISA)-HT-EM trials were evaluated in a diverse set of locations across the major wheat producing areas of South Asia with India having the largest number of locations each year (Table 1, Supplementary Table 1)
The CSISA-HT-EM trials were evaluated at major wheat producing areas in South Asia that represented the diverse temperature ranges in which wheat is grown in these regions

Summary

Introduction

An important source of calories and proteins is a key cereal crop that impacts the global economy and food security. Though wheat production in South Asia has increased dramatically since the Green Revolution, multiple challenges such as high temperature stress and reduced water availability are major concerns. Warmer temperatures have already been determined to be one of the major factors in slowing the wheat productivity growth in South Asia and globally (Gourdji et al, 2013; Pask et al, 2014; Lobell et al, 2012; Sharma et al, 2007; Joshi et al, 2007a). Estimated GY losses in South Asia can range from 6 to 10% per ◦C rise in temperature during the grain-filling period (Lobell et al, 2008; Mondal et al, 2013; Asseng et al, 2015). The current estimates by the World Bank indicate a population of 1.6 billion in South Asia, which is nearly 24%

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