Toward the Genetic Basis and Multiple QTLs of Kernel Hardness in Wheat

Abstract

Kernel hardness is one of the most important single traits of wheat seed. It classifies wheat cultivars, determines milling quality and affects many end-use qualities. Starch granule surfaces, polar lipids, storage protein matrices and Puroindolines potentially form a four-way interaction that controls wheat kernel hardness. As a genetic factor, Puroindoline polymorphism explains over 60% of the variation in kernel hardness. However, genetic factors other than Puroindolines remain to be exploited. Over the past two decades, efforts using population genetics have been increasing, and numerous kernel hardness-associated quantitative trait loci (QTLs) have been identified on almost every chromosome in wheat. Here, we summarize the state of the art for mapping kernel hardness. We emphasize that these steps in progress have benefitted from (1) the standardized methods for measuring kernel hardness, (2) the use of the appropriate germplasm and mapping population, and (3) the improvements in genotyping methods. Recently, abundant genomic resources have become available in wheat and related Triticeae species, including the high-quality reference genomes and advanced genotyping technologies. Finally, we provide perspectives on future research directions that will enhance our understanding of kernel hardness through the identification of multiple QTLs and will address challenges involved in fine-tuning kernel hardness and, consequently, food properties.

Conservation and Divergence of SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) Gene Family between Wheat and Rice

“…Wheat is one of the most important crops worldwide, providing a food supply for about 28% of the global population [1]. However, sustaining wheat yield and quality has become unprecedentedly challenging for several reasons, including the reduction of arable land area, water resource shortages, and the emergence of new pathogens and pests.…”

Construction of a novel Wheat 55 K SNP array-derived genetic map and its utilization in QTL mapping for grain yield and quality related traits

“…All these traits mentioned above are quantitative traits. Besides the known genes, previous studies have reported numerous QTLs providing genetic basis for these traits (Groos et al, 2003;Narasimhamoorthy et al, 2006;Zhang et al, 2011;Bonneau et al, 2013;Heo and Sherman, 2013;Kumar et al, 2019;Guo et al, 2020;Tu and Li, 2020;Colasuonno et al, 2021;Fradgley et al, 2022;Gudi et al, 2022). Although epistatic QTLs, which are involved in regulatory networks, are also crucial foundations for controlling complex traits, the majority of reported loci are additive QTLs (Xing et al, 2002;Malmberg and Mauricio, 2005).…”

Wheat end-use quality: State of art, genetics, genomics-assisted improvement, future challenges, and opportunities

“…Above all, grain protein content (GPC) has been a focus for both plant breeders and end-users since it directly affects nutritional value, and dough rheological and baking properties ( Joppa et al, 1997 ; Alamri et al, 2009 ; Brevis et al, 2010 ). GPC is a critical marketing characteristic and it influences the quality performance of wheat end products in general, including pasta and bread ( Mesfin et al, 1999 ; Distelfeld et al, 2006 ; Brevis et al, 2010 ; Naraghi et al, 2019 ) and it is used as one of the parameters for wheat classification ( Tu and Li, 2020 ). The price of wheat is also determined based on the GPC where wheat with higher GPC is valued more than lower GPC ( Farquharson, 2006 ).…”