Selection of M5 mutant lines of wheat (Triticum aestivum L.) for agronomic traits and biomass allocation under drought stress and non-stressed conditions

Athenkosi Makebe; Hussein Shimelis; Jacob Mashilo

doi:10.3389/fpls.2024.1314014

Selection of M5 mutant lines of wheat (Triticum aestivum L.) for agronomic traits and biomass allocation under drought stress and non-stressed conditions

Front Plant Sci. 2024 Feb 14:15:1314014. doi: 10.3389/fpls.2024.1314014. eCollection 2024.

Authors

Athenkosi Makebe¹, Hussein Shimelis¹, Jacob Mashilo^{1

2}

Affiliations

¹ African Centre for Crop Improvement (ACCI), University of KwaZulu-Natal, Pietermaritzburg, South Africa.
² Limpopo Department of Agriculture and Rural Development, Bela-Bela, South Africa.

Abstract

Introduction: In the face of climate changes and limited water availability for irrigated crop production, enhanced drought tolerance and adaptation is vital to improve wheat productivity. The objective of this study was to determine the responses of newly bred and advanced mutant lines of wheat based on agronomic traits and biomass allocation under drought-stressed and non-stressed environments for production and breeding.

Methods: Fifty-three mutant lines, including the parental check and six check varieties, were evaluated under non-stressed (NS) and drought stressed (DS) conditions in the field and controlled environments using a 20 x 3 alpha lattice design with two replicates. The following agronomic data were collected: days to 50% heading (DTH), days to maturity (DTM), plant height (PH), number of productive tillers (PTN), shoot biomass (SB), root biomass (RB), total biomass (TB), root: shoot ratio (RSR), spike length (SL), thousand seeds weight (TSW) and grain yield (GY). Data were analyzed and summarized using various statistical procedures and drought tolerance indices were computed based on grain yield under NS and DS conditions.

Results: Significant (P < 0.05) differences were recorded among the mutant lines for most assessed traits under NS and DS conditions. Grain yield positively and significantly (p < 0.001) correlated with PTN (r = 0.85), RB (r = 0.75), SB (r = 0.80), SL (r =0.73), TB (r = 0.65), and TSW (r = 0.67) under DS condition. Principal component analysis revealed three components contributing to 78.55% and 77.21% of the total variability for the assessed agronomic traits under DS and NS conditions, respectively. The following traits: GY, RB, SB, and PTN explained most of the variation with high loading scores under DS condition. Geometric mean productivity (GMP), mean productivity (MP), harmonic mean (HM), and stress tolerance index (STI) were identified as the best drought tolerance indices for the identification of tolerant lines with positive correlations with GY under NS and DS conditions.

Discussion: Among the advanced lines tested, LMA16, LMA37, LMA47, LMA2, and LMA42 were selected as the superior lines with high performance and drought tolerance. The selected lines are recommended for multi-environment trails and release for production in water-limited environments in South Africa.

Keywords: agronomic traits; biomass allocation; drought tolerance indices; mutagenesis; root-shoot ratio.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The South African Cultivar and Technology Agency (201621790608) and National Research Foundation (grant number 130017) South Africa are acknowledged for funding this study. The University of KwaZulu-Natal is acknowledged for the support of the project, as well as the University Capacity Development Grant (UCDP) for funding and research support.