Variation in stomatal conductance responses of cotton cultivars to high vapour pressure deficit under controlled and rainfed environments

Abstract

Cotton is often negatively impacted by drought periods; thus, plant traits that alleviate the impacts of drought on cotton are highly desirable. The limited‐transpiration rate (TRlim) trait under high vapour pressure deficit (VPD) can conserve soil water and prolong crop physiological activity as water deficit progresses. The current research objective was to compare the expression of TRlim in cotton cultivars under variable VPD and temperatures by whole‐plant transpiration in controlled environments and by leaf‐level gas exchange measurements in the field. All cultivars expressed the TRlim trait in a controlled environment with high VPD at 32°C; however, at 38°C, only 5 out of 7 commercial and 2 out of 4 conventional cultivars expressed TRlim. Field trials during 2017 and 2018 showed all 4 commercial cultivars that expressed TRlim in a controlled environment at 38°C expressed TRlim, but shifts in VPD breakpoints were observed. Among conventional cultivars, 2 out of 4 expressed TRlim trait. Cultivars that expressed TRlim also delayed wilting under rainfed environments when soil water deficits developed and resulted in greater lint yields. Three commercial and two conventional cultivars that expressed the TRlim trait in field trials also resulted in greater predawn leaf water potential (LWP). Cultivars that expressed the TRlim trait had significantly higher lint yields only during 2017. This study indicates that the impact of TRlim trait on yield is relatively small in years with adequate rainfall.

Effect of Cotton Leafroll Dwarf Virus on Physiological Processes and Yield of Individual Cotton Plants

“…First, healthy plants of the symptomatic cultivar possess innately higher gas exchange rates than asymptomatic cultivars, even in the absence of CLRDV. Recent research has indicated that cotton cultivars exhibit genotypic differences in their gas exchange response to vapor pressure deficit (VPD; Shekoofa et al, 2021). For example, VPD will increase as air temperature increases or relative humidity decreases.…”

“…In both seasons, plants with CLRDD symptoms of varying severity were consistently observed in the early season for cotton cultivar DG 3615 B3XF (symptomatic cultivar, S), whereas other cultivars at the same sites exhibited 0% disease incidence (asymptomatic cultivars, A). Since some cotton cultivars have recently been shown to differ in their stomatal response to vapor pressure deficit (Shekoofa et al, 2021), otherwise normal plants of A and S cultivars may exhibit inherent differences in gas exchange responses under the same field conditions. It was hypothesized that diseased plants of the symptomatic cultivar would exhibit lower light-saturated photosynthetic rates, reduced photochemical efficiencies of photosystem II, declines in stomatal conductance, increased leaf temperature, and reduced productivity relative to plants of the same cultivar without conspicuous disease symptoms.…”

Phenotyping and Quantitative Trait Locus Analysis for the Limited Transpiration Trait in an Upper-Mid South Soybean Recombinant Inbred Line Population (“Jackson” × “KS4895”): High Throughput Aquaporin Inhibitor Screening

“…If the slopes differed, the double-linear regression was retained. When the slopes were not significantly different, a simple linear regression was applied to all the data ( Devi et al, 2010 ; Shekoofa et al, 2020 ).…”

“…However, it is suggested that under extreme drought or high atmospheric vapor pressure deficit (VPD) conditions, restriction of stomatal conductance might increase photosynthetic return per unit of transpiration ( Sinclair et al, 2005 , 2010 ; Devi et al, 2009 ; Gholipoor et al, 2010 ; Carpentieri-Pipolo et al, 2012 ; Gaffney et al, 2015 ; Shekoofa et al, 2020 ). These traits result in restricted TR under high vapor pressure conditions, such that water is conserved in the soil and is available during subsequent drought periods.…”

“…These studies also suggested that reduced TR and stomatal conductance are controlled by gene expression. Such mechanisms have been successfully studied in crop species, including: maize ( Zea Mays L.) ( Fletcher et al, 2007 ; Shekoofa et al, 2016 ), peanut ( Arachis hypogaea L.) ( Devi et al, 2009 ; Shekoofa et al, 2013 , 2017 ), cotton ( Gossypium hirsutum L.) ( Devi and Reddy, 2018b ; Shekoofa et al, 2020 ), sorghum ( Sorghum bicolor L.) ( Gholipoor et al, 2010 ; Choudhary et al, 2013 ), and soybean [ Glycine max (L.) Merr.] ( Bunce, 1981 ; Devi et al, 2014 ; Sarkar et al, 2021b ).…”