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

Zakaria Al-Ajlouni,Ayed Al-Abdallat,Abdul Al-Ghzawi,Jamal Ayad,P Baenziger,Nisreen Al-Quraan,Jamal Abu Elenein

doi:10.3390/agronomy6020033

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.

Highlights

Barley (Hordeum vulgare L.) is a widely cultivated cereal crop in many rainfed areas in the Mediterranean region where drought is considered the main yield-limiting factor [1,2]
Knowing that yield has two major components, grain number per unit area and grain weight, with grain number being determined during the pre-anthesis stage, while grain weight is determined at the post-anthesis stage, it is critical to study drought stress in the pre-anthesis and post-anthesis stages
Barley is adapted to a wide range of environments due to allelic diversity in VRN and PPD genes [18].the current study examined the response of heading date, yield, yield components and other physiological traits to drought occurred in barley plants at two different pre-anthesis growth stages: tillering stage and stem elongation stage, according to the expected situations of climatic change for the Mediterranean region

Summary

Introduction

Barley (Hordeum vulgare L.) is a widely cultivated cereal crop in many rainfed areas in the Mediterranean region where drought is considered the main yield-limiting factor [1,2] In such marginal lands, yield losses is associated with drought conditions resulted from low and inconsistent precipitation during the whole plant growth cycle, either early in the fall or winter Barley is characterized by its fast pre-anthesis growth and its ability to form large number of tillers that cover soil surface and subsequently reduce water evaporation. This trait explains why barley is highly successful in dry areas [2,5]. The successful establishment of barley at early growth stages under dry environments is needed for high productivity (i.e., higher grain number production) [10]

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