Crosses with spelt improve tolerance of South Asian spring wheat to spot blotch, terminal heat stress, and their combination

Ajeet Kumar Pandey,Arun Kumar Joshi,Sudhir Navathe,Ramesh Chand,Vinod Kumar Mishra,Sandeep Sharma,Neeraj Budhlakoti,Jayasudha Srinivasa

doi:10.1038/s41598-021-85238-x

Abstract

Spot blotch and terminal heat are two of the most important stresses for wheat in South Asia. A study was initiated to explore the use of spelt (Triticum spelta) to improve tolerance to these stresses in spring wheat (T. aestivum). We assessed 185 recombinant inbred lines (RILs) from the cross T. spelta (H + 26) × T. aestivum (cv. HUW234), under the individual stresses and their combination. H + 26 showed better tolerance to the single stresses and also their combination; grain yield in RILs was reduced by 21.9%, 27.7% and 39.0% under spot blotch, terminal heat and their combined effect, respectively. However, phenological and plant architectural traits were not affected by spot blotch itself. Multivariate analysis demonstrated a strong negative correlation between spikelet sterility and grain yield under spot blotch, terminal heat and their combination. However, four recombinant lines demonstrated high performance under both stresses and also under their combined stress. The four lines were significantly superior in grain yield and showed significantly lower AUDPC than the better parent. This study demonstrates the potential of spelt wheat in enhancing tolerance to spot blotch and terminal heat stresses. It also provides comprehensive evidence about the expression of yield and phenological traits under these stresses.

Highlights

IntroductionIt is estimated that 10 Mha of wheat are affected by spot blotch in South Asia, of which 9 Mha are within India a lone[6]
Spot blotch and terminal heat are two of the most important stresses for wheat in South Asia
Even in the absence of rainfall, high relative humidity arising from soil residual moisture along with foggy days cause prolonged wetness on leaf blades and sheath that can last until late January to first fortnight of February, creating ideal conditions for the establishment and multiplication of p athogen[20]

Summary

Introduction

It is estimated that 10 Mha of wheat are affected by spot blotch in South Asia, of which 9 Mha are within India a lone[6] Most of it falls under the rice–wheat cropping system which often provides an environment favourable for the survival and multiplication of foliar blight pathogens, due to late sowing of wheat after the preceding paddy crop[6]. This disease has become a major wheat production constraint in the EGP and in warmer regions worldwide[6,8] including North and Latin A merica9, Brazil[10], and to some extent in parts of Europe Terminal heat, another major stress in wheat, is estimated to affect approximately 13.5 Mha of the wheatgrowing area (~ 40% of the total irrigated area) in India alone[11]. Common tolerance mechanisms have sparsely been reported to combat both spot blotch and terminal heat stress

Methods

Results

Conclusion