Relationships between Grain Yield, Flag Leaf Morphology, Carbon Isotope Discrimination and Ash Content in Irrigated Wheat

Abstract

The purpose of this study was to examine how differences in leaf angle, leaf rolling (LR) and glaucousness (GL) can modify yield components and leaf physiological traits in wheat. A set of 167 lines derived from a cross between two high-yielding bread wheat cultivars differing for these traits was grown under flood irrigation and high evaporative demand in the north-west of Mexico. Area, mass per unit area and chlorophyll content of the flag leaf were assessed. Carbon isotope discrimination (D) and ash content (m a ) were also measured. A significant correlation was found between grain yield (GY) and both D and m a suggesting that, despite well-watered conditions, leaf stomatal conductance was the main yield-limiting factor. Leaf posture and LR did not significantly affect yield, D and m a . Higher grain weight was noted, however, in lines with droopy flag leaves. Erect leaves had higher mass per unit area. GL was associated with a significant increase in GY and grain weight. Glaucous lines also had higher D and m a , suggesting higher transpiration rate and lower transpiration efficiency. The study confirms that D and m a represent promising criteria for GY in wheat and provides evidence that GL can contribute to higher yield, even under irrigated conditions.

Mapping of a gene (Vir) for a non-glaucous, viridescent phenotype in bread wheat derived from Triticum dicoccoides, and its association with yield variation

“…It is possible therefore that Vir is either closely linked to W1, or is the same gene. It should be noted however that historically, glaucousness has been found to have a positive relationship with yield, especially under drought stressed conditions (Richards et al 1986;Monneveux et al 2004), whereas in the present study, the converse was found. Additionally, W1 has been located 4 cM distal to Lr16 and Sr23 (http://www.wheat.pw.usda.gov/GG2/index.shtml), which are in turn located a further 12 cM from Xgwm614 (Somers et al 2004).…”

Differential gene expression of wheat progeny with contrasting levels of transpiration efficiency

“…A surrogate measure of TE is carbon isotope discrimination (D 13 C), which is a measure of the 13 C/ 12 C ratio in plant material relative to the ratio in atmospheric CO 2 (Hall et al 1994). D 13 C values have been shown to be inversely correlated with TE in wheat Monneveux et al 2004) and other C 3 crop species (Hubick et al 1986;1988;Teulat et al 2003;Lambrides et al 2004), as well as with grain yield when water is limiting.…”

Long noncoding miRNA gene represses wheat β-diketone waxes

“…Reduced light absorption can lower tissue temperatures, thereby reducing transpirational water loss, and also may reduce photosynthesis under nonsaturating illumination (1). In wheat, a glaucous appearance has been shown to be associated with stabilizing grain yield, particularly in growth environments that are water-limited and prone to heat stress (6,8,9). Thus, because of the protective nature of the waxy β-diketone layer, the glaucous appearance has generally been selected for during the breeding of cultivated durum and bread wheat varieties (3,10).…”