Quantitative characterization of proximate sensing canopy traits in the SoyNAM population

Abstract

The average increase of soybean [Glycine max (L.) Merr.] grain yield per year is not enough to meet the estimated need by 2050. Contributing factors may include narrowing genetic diversity in cultivated soybean germplasm arising from direct selection for grain yield and insufficient knowledge of the genetic influences on physiological traits associated with grain yield. Canopy development plays a critical role in the light intercepted by soybean crops throughout the growing season. Rapid canopy closure facilitates complete light interception and optimizes growth dynamics, ultimately increasing biomass accumulation and grain yield. This study sought to use ground-based digital imagery as a phenotyping tool for quantitative characterization of seasonal canopy coverage and light interception in the genetically diverse Soybean Nested Association Mapping (SoyNAM) population. We took weekly measurements of canopy coverage from early vegetative to mid-reproductive growth for 5,600 recombinant inbred lines during the 2013 and 2014 seasons. An asymptotic logistic growth curve fit to the coverage data allowed us to estimate daily changes in canopy coverage in the intervals between the sampling dates, enabling calculation of canopy dynamic parameters. These parameters included average canopy coverage, cumulative intercepted photosynthetically active radiation for the total sampling period, vegetative growth period, reproductive growth period, and the number of days required to reach 30, 50, and 70% canopy coverage. Variance component estimation showed that genetic differences among families significantly influenced variation in phenotypic expression for all canopy parameters. The narrow-sense heritabilities for all canopy parameters were high (h 2 = .81-.90), suggesting opportunities for genetic gains in canopy development through selection of superior genotypes.

Association between unmanned aerial vehicle high‐throughput canopy phenotyping and soybean yield

“…However, of the few studies in the literature about the association between canopy coverage and yield, most of them only address an association of phenotypical nature. Often, it does not translate the cause–effect relationship (Hall et al., 2020; Hoyos‐Villegas et al., 2015; Moreira et al., 2019). Estimates of positive association found in this study between GY and canopy coverage (Figure 4) corroborate previous studies (Jarquin et al., 2018; Kaler et al., 2018; Xavier, Hall, Hearst, et al., 2017).…”

“…The influence of a third variable can trigger a series of physiological mechanisms that make the positive correlation embody a null or opposite direction (Falconer & Mackay, 1966). Hall et al (2020) assessed the canopy coverage in a highly diverse population based on the Soybean Nested Association Mapping Dataset (SoyNam), which observed phenotypical correlation between grain yield and canopy coverage of 0.36 (20 DAS), 0.32 (27 DAS), 0.26 (34 DAS), 0.24 (40 DAS), 0.23 (48 DAS), and 0.23 (56 DAS). However, when grain yield was correlated to accumulated active photosynthetic radiation, it ranged from 0.67 and 0.61 in the vegetative and reproduction periods, respectively.…”