Use of Chlorophyll Fluorescence Assessments to Differentiate Corn Hybrid Response To Variable Water Conditions

Abstract

Development of corn (Zea mays L.) germplasm tolerant to water stress will be vital to sustaining corn‐based farming in the U.S. Great Plains. In a companion 4‐yr field study near Shelton, NE, we found that 12 hybrids displayed differential agronomic responses to varying water levels, with tolerant hybrids yielding from 27 to 42% more than susceptible hybrids under stress while yielding similarly under no stress. The objective of this study was to determine if chlorophyll fluorescence (CF) measurements could be used to distinguish tolerant from susceptible hybrids. Leaf temperature (LT) and two CF parameters (ΦPSII, photosystem II quantum efficiency, and ETR, electron transport rate) were measured on three postflowering dates in 2001 using a fluorometer on a subset of original treatments involving two tolerant and susceptible hybrids grown under deficit and adequate water. Water effects were observed on only one date; LT was 2.5°C warmer and ΦPSII and ETR values were 25% lower for deficit vs. adequate water just after silking, signifying increased water stress and decreased photosynthesis during reproductive growth. Under stress, LTs were 2.8°C cooler and ΦPSII and ETR values 50% higher for tolerant vs. susceptible hybrids, while all hybrids produced similar CF values under no stress. Thus, grain yield and photosynthetic responses of hybrids to stress were similar, indicating that CF measurements can be used to distinguish tolerant from susceptible hybrids.

Use of physiological parameters as fast tools to screen for drought tolerance in sugarcane

“…Therefore, these parameters might be used as a selection criterion for stalk productivity in sugarcane under drought stress. This is in accordance to Araus et al (1998), O'Neill et al (2006) and Rong-hua et al (2006) that worked with wheat, corn and barley, respectively.…”

“…the consequences of drought stress that may result from sustained photoinhibition and photo-bleaching (Long et al, 1994), and even though other plant processes, such as cell division and cell expansion are the earliest to respond to water deficit stress (Dale, 1988), a decline in SPAD index is a sensitive and readily measurable trait that could be used to screen for stress tolerance (O'Neill et al, 2006). The distribution of SPAD index values among the sugarcane genotypes used in this study is consistent with their tolerance-susceptibility classification, with the exception of the genotype TCP02-4587 at 90 DAT.…”

“…For instance, differences in dry matter accumulation between old and new corn hybrids have been shown to depend on the ability to maintain higher photosynthetic rates after silking for newer hybrids (Tollenaar and Aguilera, 1992). O'Neill et al (2006) also hypothesized that photosynthetic rates of drought tolerant corn hybrids were higher than those of susceptible hybrids during the critical post-flowering growth period and concluded that photosynthetic assessments during this growth stage could be useful in identifying stress tolerant genotypes.…”

“…The reliability of these parameters to distinguish between stress tolerant and susceptible genotypes seems to depend on the species under consideration (Colom and Vazzana, 2003;O'Neill et al, 2006;Rong-hua et al, 2006) since different species may possess different mechanisms of stress resistance and/or tolerance. To our knowledge, no studies have evaluated these relationships in sugarcane.…”

Sugarcane Response to Water-Deficit Stress during Early Growth on Organic and Sand Soils

“…2d). O'Neill et al (2006) suggested that ΦPSII measurements can be used to distinguish tolerant from susceptible corn hybrids under drought conditions. Our results indicated that changes in ΦPSII during development of water stress (Fig.…”