Genetic variation in heat tolerance-related traits in a population of wheat multiple synthetic derivatives

Abstract

In wheat (Triticum aestivum L.) high temperature (≥30°C) during grain filling leads to considerable reduction in grain yield. We studied 400 multiple synthetic derivatives (MSD) lines to examine the genetic variability of heat stress-adaptive traits and to identify new sources of heat tolerance to be used in wheat breeding programs. The experiment was arranged in an augmented randomized complete block design in four environments in Sudan. A wide range of genetic variability was found in most of the traits in all environments. For all traits examined, we found MSD lines that showed better performance than their parent 'Norin 61' and two adapted Sudanese cultivars. Using the heat tolerance efficiency, we identified 13 highly heat-tolerant lines and several lines with intermediate heat tolerance and good yield potential. We also identified lines with alleles that can be used to increase wheat yield potential. Our study revealed that the use of the MSD population is an efficient way to explore the genetic variation in Ae. tauschii for wheat breeding and improvement.

Keywords: bread wheat; drought; germplasm enhancement; heat stress; wild species.

Fig. 1

Weekly maximum and minimum temperatures at Dongola (DON), Hudeiba (HUD), and Gezira (Wad Medani; MED) Research Farms starting from the 4 th of November. OS, optimum sowing; LS, late sowing; S, sowing time; V, vegetative stage; H, heading stage; M, maturity stage.

Fig. 2

Frequency distribution of days to heading (A), days to maturity (B) and grain filling duration (C) of the MSD lines, their parent ‘Norin 61’ (triangle) and the adapted Sudanese cultivars ‘Goumria’ (black rhombus) and ‘Imam’ (white rhombus) of four environments of Dongola (DON), Wad Medani optimum sowing (MED/OS), Hudieba (HUD) and Wad Medani late sowing (MED/LS) in 2015/16.

Fig. 3

Frequency distribution of plant height (A) and peduncle length (B) of the MSD lines, their parent ‘Norin 61’ (triangle) and the adapted Sudanese cultivars ‘Goumria’ (black rhombus) and ‘Imam’ (white rhombus) of four environments of Dongola (DON), Wad Medani optimum sowing (MED/OS), Hudieba (HUD) and Wad Medani late sowing (MED/LS) in 2015/16.

Fig. 4

Frequency distribution of canopy temperature (A) chlorophyll content (B) and normalized difference vegetation index (C) of the MSD lines, their parent ‘Norin 61’ (triangle) and the adapted Sudanese cultivars ‘Goumria’ (black rhombus) and ‘Imam’ (white rhombus) of four environments of Dongola (DON), Wad Medani optimum sowing (MED/OS), Hudieba (HUD) and Wad Medani late sowing (MED/LS) in 2015/16.

Fig. 5

Frequency distribution of kernel number per spike (A), thousand-kernel weight (B) and grain number per m² (C) of the MSD lines, their parent ‘Norin 61’ (triangle) and the adapted Sudanese cultivars ‘Goumria’ (black rhombus) and ‘Imam’ (white rhombus) of four environments of Dongola (DON), Wad Medani optimum sowing (MED/OS), Hudieba (HUD) and Wad Medani late sowing (MED/LS) in 2015/16.

Fig. 6

Frequency distribution of grain yield (A), biomass (B) and harvest index (C) of the MSD lines, their parent ‘Norin 61’ (triangle) and the adapted Sudanese cultivars ‘Goumria’ (black rhombus) and ‘Imam’ (white rhombus) of four environments of Dongola (DON), Wad Medani optimum sowing (MED/OS), Hudieba (HUD) and Wad Medani late sowing (MED/LS) in 2015/16.

Fig. 7

Regression analysis of the relationship between grain yield at DON and heat tolerance efficiency DON (considered a cool environment) and at MED/LS (hot environment) (A) and relationship between grain yield at MED/OS and heat toleance efficiency MED/OS (considered a cool environment) and at MED/LS (considered a hot environment) (B) for the MSD lines, their parent ‘Norin 61’ (control), and the adapted Sudanese cultivars ‘Goumria’ and ‘Imam’. Red dots, highly heat-tolerant lines; dark orange dots, moderately heat-tolerant lines with good grain yield.