Rapid On-Site Phenotyping via Field Fluorimeter Detects Differences in Photosynthetic Performance in a Hybrid—Parent Barley Germplasm Set

Abstract

Crop productivity can be expressed as the product of the amount of radiation intercepted, radiation use efficiency and harvest index. Genetic variation for components of radiation use efficiency has rarely been explored due to the lack of appropriate equipment to determine parameters at the scale needed in plant breeding. On the other hand, responses of the photosynthetic apparatus to environmental conditions have not been extensively investigated under field conditions, due to the challenges posed by the fluctuating environmental conditions. This study applies a rapid, low-cost, and reliable high-throughput phenotyping tool to explore genotypic variation for photosynthetic performance of a set of hybrid barleys and their parents under mild water-stress and unstressed field conditions. We found differences among the genotypic sets that are relevant for plant breeders and geneticists. Hybrids showed lower leaf temperature differential and higher non-photochemical quenching, resembling closer the male parents. The combination of traits detected in hybrids seems favorable, and could indicate improved photoprotection and better fitness under stress conditions. Additionally, we proved the potential of a low-cost, field-based phenotyping equipment to be used routinely in barley breeding programs for early screening for stress tolerance.

The love-hate relationship between chlorophyll a and water in PSII affects fluorescence products

“…Leaf characteristics for sage and pine derive from a leaf life span greater than one growing season so they come with tradeoffs of hardiness vs. light harvesting and overall photosynthetic capacity (Wright et al 2004). Past calibration equations for the SPAD measurements were usually species-specific reflecting traits such as leaf thickness and leaf succulence (Richardson et al 2002, Uddling et al 2007, Fernández-Calleja et al 2020. Our study indicates that leaf thickness and secondary leaf characteristics (Table 1) lead to species-specific behavior in RChlF in fully hydrated samples, but that species variation decreases when hydration decreases (Fig.…”

High-Throughput Phenotyping Methods for Breeding Drought-Tolerant Crops

“…McAusland et al [ 52 ] proposed an experimental method for observing photosynthesis and the photoprotection of crops in various light environments through fluorescence analysis. Likewise, in the field, photosynthetic efficiency can be analyzed by measuring the chlorophyll fluorescence of a target plant using a portable fluorescence meter in a drought-stress or well-watered environment [ 53 , 54 , 55 ].…”

“…Chlorophyll fluorescence [53][54][55] In this review, we used the search engine Scopus (https://www.scopus.com/search/ form.uri?display=basic#basic, accessed on 28 June 2021) to investigate the flow of mass testing of drought traits between 2007 and April 2021. The search was conducted using keywords including high-throughput, phenotyping, and drought, and we identified 248 articles.…”

Impact of soil salinity on mangrove restoration in a semiarid region: a case study from the Saloum Delta, Senegal

“…We measured stomatal conductance (mmol m −2 second −1 ) of the uppermost fully expanded leaf of seedlings using a diffusion porometer (Leaf Porometer, model SC‐1; Decagon Devices Inc., Pullman, WA, U.S.A.). PSII operating efficiency (or ΦPSII; quantum yield of PSII) and leaf relative chlorophyll content (SPAD) were also measured on the uppermost fully expanded leaf using a MultispeQ plant phenotyping tool (Kuhlgert et al 2016; Fernández‐Calleja et al 2020). Because of the length of time required to record physiological parameters (particularly associated with calibration of the diffusion porometer, ~5 min per measurement), and the need for relatively stable ambient environmental conditions to allow for within‐site comparison, we randomly sub‐sampled 3–5 individuals (when present) per plot for physiological measurements.…”