Impact of Pre-Anthesis Water Deficit on Yield and Yield Components in Barley (Hordeum vulgare L.) Plants Grown under Controlled Conditions

Abstract

Drought at pre-anthesis stages can influence barley growth and results in yield losses. Therefore, it is important to understand how drought at pre-anthesis can affect different traits associated with yield reduction in barley. The objective of this study was to understand the relevance of the genetic background of major flowering time genes in barley plants subjected to pre-anthesis drought and its impact on yield and yield components. A glasshouse experiment using a Randomized Complete Block Design was conducted to investigate the effect of drought and its timing on yield and yield components on eleven barley genotypes, which were selected to represent genetic diversity of major flowering time genes (PPDH1, PPDH2, HvVrn1, HvVrn2 and HvVrn3). Barley plants were exposed to three water regimes, non-stressed and stressed, which was applied at two pre-anthesis growth stages, tillering (SS) and stem elongation (SE). Results identified differences among genotypes in all measured traits. Grain yield, grain number and "thousand kernel weight" were reduced in all genotypes due to drought, irrespective of the growth stage. Early flowering genotypes had better performance as reflected in higher yield compared with late flowering genotypes. Results verified the fundamental importance of early flowering to improve productivity in response to pre-anthesis drought. The results of this study can help in selecting barley lines for future breeding purposes with improved resilience to drought conditions in Mediterranean environments.

Barley yield formation under abiotic stress depends on the interplay between flowering time genes and environmental cues

“…We observed a trend that late plant development (Table 2). Here, elevated temperatures and low rainfall restricted plant growth to a few months and thus earliness is a major breeding goal 48,49 . In future, this situation may intensify, since climate change is expected to further shorten the growing period in drought and heat prone locations like in Jordan 26,32,50 .…”

“…In those areas where drought and heat affect plant development and grain maturation, early maturing lines like HEB_05_043, HEB_15_082 or HEB_10_173 may be beneficial because of their fast development ( Figure 5; Supplementary Figure S9; Supplementary Table S10a). Moreover, the increased tiller capacity of HEB-YIELD lines may be promising to achieve an improved canopy cover, reducing moisture losses 26,49 and to increase biomass yield. The latter trait may be high value in the eastern part of the Mediterranean basin where straw and grains of barley are mainly used for animal feeding 91,92 .…”

The Effect of Supplemental Irrigation on Canopy Temperature Depression, Chlorophyll Content, and Water Use Efficiency in Three Wheat (Triticum aestivum L. and T. durum Desf.) Varieties Grown in Dry Regions of Jordan

“…In Jordan, water deficit is the most limiting factor for wheat yield in most years [13]. The unfavorable distribution of rain over the growing season and the year-to-year fluctuations constitute a major constraint to wheat growth and yield [50][51][52][53][54].…”

“…Such models have also predicted an increase of 3-5 • C in temperature [11] and around a 20% loss in soil moisture [12], supported by the fact that wheat production suffered from yield variability from year to year and from one location to another, caused by drought stress. Drought may occur pre-anthesis and negatively affect crop establishment and floret fertility [13,14] or post-anthesis and adversely affect grain filling and grain development [15]. Therefore, improvement of wheat productivity under drought conditions became the main objective of the current breeding programs in arid and semi-arid regions.…”

Optimizing irrigation and determining the most sensitive development stage to drought in barley (Hordeum vulgare L.) in a semi-arid environment

“…The study of Al-Ajlouni et al (2016) showed a huge impact of pre-anthesis water deficit on barley yield components due to water deficit stress during tillering and stem elongation stages, whereas in the Mediterranean zone cereal crops are exposed to frequent post-anthesis water deficit. Our results indicate that water deficit stress affects yield components to varying degrees, according to the development stages.…”