Grain quality of elite bread wheat genotypes under non-stress and drought-stress conditions. Issue 3 (3rd May 2020) - Thungo, Zamalotshwa
ABSTRACT: Grain quality, including protein content, is a key determinant of marketability and end-user acceptance of bread wheat ( Triticum aestivum L.). This study determined the grain quality of bread wheat genotypes under simulated terminal drought (TD) and well-watered (WW) conditions for selecting suitable genotypes for breeding. The amount of gliadin (Gli), gluten (Glu), glutenin (Glut), gliadin: glutenin ratio (Gli: Glut ratio) and total protein content (TPC) were determined in 24 elite heat- and drought-tolerant bread wheat genotypes sourced from the International Maize and Wheat Improvement Center (CIMMYT). The experiment was conducted under rainout shelter (RS) and glasshouse (GH) environments. Genotype-by-environment interaction was significant ( p ≤ 0.001) for grain quality traits. Positive correlations were observed between Gli and Gli : Glut ratio (r = 0.97), and Glut and Glu (r = 0.97). The correlation between Glut and Gli : Glut ratio was negative (r = -0.58) under TD condition. Under TD condition and in RS, positive but relatively small correlations were found between TPC and Gli ( r = 0.19), Glut ( r = 0.16), Gli: Glu ratio ( r = 0.04) and Glu ( r = 0.22). The trend was similar under GH condition in TD where positive and low correlation values were detected between TPC and Gli (r = 0.19), Glut ( r = 0.29), Gli: Glu ratio ( r = 0.14) and Glu ( r = 0.33). This suggested selection for higher TPC may result in limited improvement of protein-fractions. Heat- and drought-tolerant wheat genotypes, such as LM95, LM90, LM85, LM82, LM73, LM71, LM62, LM60, LM55, LM44, and LM41, with improved quality attributes, were identified for breeding and production.