Dissecting Bread Wheat Heterosis through the Integration of Agronomic and Physiological Traits

Abstract

To meet the challenge of feeding almost 10 billion people by 2050, wheat yield has to double by 2050. However, over the past 20 years, yield increase has slowed down and even stagnated in the main producing countries. Following the example of maize, hybrids have been suggested as a solution to overcome yield stagnation in wheat. However, wheat heterosis is still limited and poorly understood. Gaining a better understanding of hybrid vigor holds the key to breed for better varieties. To this aim, we have developed and phenotyped for physiological and agronomic traits an incomplete factorial design consisting of 91 hybrids and their nineteen female and sixteen male parents. Monitoring the plant development with normalized difference vegetation index revealed that 89% of the hybrids including the five higher yielding hybrids had a longer grain filling phase with a delayed senescence that results in larger grain size. This average increase of 7.7% in thousand kernel weight translated to a positive mid-parent heterosis for grain yield for 86% of hybrids. In addition, hybrids displayed a positive grain protein deviation leading to a +4.7% heterosis in protein yield. These results shed light on the physiological bases underlying yield heterosis in wheat, paving new ways to breed for better wheat hybrids.

Recent advances in the genetics underlying wheat grain protein content and grain protein deviation in hexaploid wheat

“…Hybrids have also shown earlier heading and a longer senescence phase compared to the parents, resulting in a longer grain filling period (Gimenez et al . 2021). This finding adds support to the significance of post‐anthesis nitrogen uptake previously reported to be associated with GPD (Bogard et al .…”

Disentangling the Heterosis in Biomass Production and Radiation Use Efficiency in Maize: A Phytomer-Based 3D Modelling Approach

“…Previous studies mainly focused on the heterosis of photosynthetic traits at the leaf level, leaf area at the plant level, and yield components. However, the heterosis in RUE has rarely been adequately quantified [ 7 , 8 ]. Incomplete information, as well as lack of precise and insufficient methods in determining and analyzing traits in traditional field experimental study, may impede our in-depth understanding of the relationship between crop structure and PAR interception, which in turn affects the precise quantification of RUE [ 9 , 10 ].…”

Wheat Breeding, Transcription Factories, and Genetic Interactions: New Perspectives

“…Rates of wheat yield improvements have slowed in recent years to 0.5–0.9% per year, and there is much concern about achieving the additional yields necessary to feed the world using less land and with fewer inputs ( Ray et al, 2013 ). There is, therefore, a need to continuously seek better and more informed ways of approaching plant breeding, including the making of commercial hybrids ( Boeven et al, 2020 ; Gimenez et al, 2021 ). Wheat is a polyploid.…”

“…Genetic interactions can be between alleles at a single locus or epistatically between pairs of or many non-allelic loci inter- or intrachromosomally ( Jiang et al, 2017 ; Mackay et al, 2021 ). Such interactions could be within the nucleus affecting transcriptional and posttranscriptional regulatory steps but could also be between pathways and networks underpinning interacting traits ( Schnell and Cockerham, 1992 ; Gimenez et al, 2021 ). No doubt numerous mechanisms giving rise to positive and negative attributes are frequent in nature.…”