Breeding has selected for architectural and photosynthetic traits in lentils

Abstract

Genetic progress in seed yield in lentils (Lens culinaris Medik) has increased by 1.1% per year in Australia over the past 27 years. Knowing which plant traits have changed through breeding during this time can give important insights as to how lentil yield has increased. This study aims to identify morphological and physiological traits that were directly or indirectly selected between 1993 and 2020 in the Australian lentil breeding program using 2 years of experimental data. Major changes occurred in plant architecture during this period. Divergent selection has seen the release of varieties that have sprawling to very upright types of canopies. Despite this genetic diversity in recently released varieties, there is an overall tendency of recently released varieties having increased plant height and leaf size with reduced number of branches. Increased light interception was positively correlated with year of release (YOR) and yield, and likely results from indirect selection of yield and taller plant types. There is an indication that recently released varieties have lower CO2 assimilation rate, stomatal conductance and canopy temperature depression (CTD) at high ambient temperatures (~30°C). Understanding lentil physiology will assist in identifying traits to increase yield in a changing climate with extreme weather events.

Genomic selection for target traits in the Australian lentil breeding program

“…Over the years, lentil breeding in Australia has achieved significant success in enhancing grain yield through the utilization of conventional breeding methods and effective management practices. This continuous effort has resulted in an encouraging annual increase in the rate of genetic gain, averaging c. 1.2% over the past three decades ( Sadras et al., 2021 ; Silva-Perez et al., 2022 ). However, to address increasing global demand for plant-based protein, it is crucial to explore new tools and technologies such as GS, which has the potential to further increase the rate of genetic gain, particularly in environments that are prone to abiotic and biotic stresses.…”

Mapping and quantifying unique branching structures in lentil (Lens culinaris Medik.)

“…This work is of importance because these are key traits-of-interest for lentil breeders owing to the potential of these traits to influence yield and harvestability [ 18 , 19 ]. In recent decades, breeding efforts have resulted in the release of lentil cultivars with increased height and a reduced number of branches [ 3 ] which aids in mechanical harvesting and can lead to improved yield whilst reducing lodging [ 20 ]. However, the ability to screen diverse lentil lines and accurately phenotype their branch structures in a high-throughput quantitative manner has previously posed challenges, limiting the breeding of new cultivars that combine favourable architectural properties with other desirable traits to enhance productivity.…”

“…The widespread and increased cultivation of lentils in Australia has been facilitated by extensive plant breeding efforts over successive decades, which have significantly contributed to yield gains [ 3 ]. Over time, breeders have focused on improving disease resistance, abiotic stress tolerance, plant phenology and seed quality traits, all leading to better and stable yields.…”

“…Recent studies suggest that crop architecture has also played a key role in yield gains in Australian national lentil breeding programs over the past 27 years and increased plant height and leaf size along with reduced branching, changes that are positively correlated with yield. Whilst breeders have been modifying crop architecture through the direct selection of these traits, they were not correlated with the year of variety release, which indicates the usefulness of these traits for increasing yield has not yet been fully realised in Australian lentil breeding programmes [ 3 ]. Accurate selection in plant breeding programs relies heavily on precise phenotyping, which involves the quantitative measurement of various complex traits such as growth, development, tolerance, resistance, architecture, physiology, and yield [ 4 ].…”

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“…However, there is an enormous genotypic and phenotypic variability among these genetic materials, being that the majority of these cultivars have a high number of non-dominant lateral branching and few branches with dominant growth and erect stem (Cici et al, 2008;Singh et al, 2019;Liber et al, 2021). These intrinsic agronomic characteristics need to be improved since nowadays typical chickpea and lentil cultivars have a highly complex architecture for open-field management, making mechanical harvesting difficult and increasing lodging and susceptibility to biotic and abiotic stresses (Silva-Perez et al, 2022;Tripathi et al, 2022).…”