Differential manipulation of leaf angle throughout the canopy: current status and prospects

Abstract

Leaf angle is defined as the inclination between the midrib of the leaf blade and the vertical stem of a plant. This trait has been identified as a key component in the development of high-yielding varieties of cereal species, particularly maize, rice, wheat, and sorghum. The effect of leaf angle on light interception efficiency, photosynthetic rate, and yield has been investigated since the 1960s, yet, significant knowledge gaps remain in understanding the genetic control of this complex trait. Recent advances in physiology and modeling have proposed a plant ideotype with varying leaf angles throughout the canopy. In this context, we present historical and recent evidence of: (i) the effect of leaf angle on photosynthetic efficiency and yield; (ii) the hormonal regulation of this trait; (iii) the current knowledge on its quantitative genetic control; and (iv) the opportunity to utilize high-throughput phenotyping methods to characterize leaf angle at multiple canopy levels. We focus on research conducted on grass species of economic importance, with similar plant architecture and growth patterns. Finally, we present the challenges and strategies plant breeders will need to embrace in order to manipulate leaf angle differentially throughout the canopy and develop superior crops for food, feed, and fuel production.

Changes in the vertical distribution of leaf area enhanced light interception efficiency in maize over generations of selection

“…The correlation between vertical distribution of leaf area and leaf erectness suggests that the latter has appreciably contributed to the former. Leaf erectness has been identified as a heritable trait and a key component of high‐yielding varieties in cereals species (Mantilla‐Perez & Salas Fernandez, ). We confirm here that erectness largely contributes to light interception and its penetration within the canopy (Burgess et al, ; Truong, McCormick, Rooney, & Mullet, ) and that it has been indirectly selected by breeders.…”

Photosynthetic Metabolism under Stressful Growth Conditions as a Bases for Crop Breeding and Yield Improvement

“…Changes in leaf angle and plant architecture are features of interest in cereal breeding programs [170,171]. Several QTLs related to leaf angle have been identified in maize and rice ( [172] and references therein), bread wheat [173][174][175], and durum wheat [176], as well as genes associated with changes in leaf angle in maize, rice, and sorghum [172]. On the other hand, the association between QTLs and stay-green has been reported in wheat [137,143,177,178], maize [140,[179][180][181][182], barley [141], sorghum [183][184][185][186], and rice [187].…”

Wheat TaSPL8 Modulates Leaf Angle Through Auxin and Brassinosteroid Signaling

“…Leaf angle, defined as the inclination between the leaf blade midrib and the stem, directly influences canopy structure and consequentially affects yield (Mantilla-Perez and Salas Fernandez, 2017). Plants with erect leaves have an increased capacity to intercept light and higher photosynthetic efficiency, which results in improved grain filling (Sinclair and Sheehy, 1999).…”