Effect of moderate and severe drought stress on the pre-anthesis development and yield formation of oats

P Peltonen-Sainio

doi:10.23986/afsci.72417

Abstract

Greenhouse experiments were conducted at the University of Helsinki, Department of Crop Husbandry in 1989 and 1990 to provide information on the effects of drought stress on the developmental rate of the panicle, formation and abortion of florets, and formation of yield components in two oat cultivars, both adapted to the northern marginal growing conditions. Moderate water deficit and severe drought stress did not affect the developmental rate of the panicle, but the pre-anthesis and post-anthesis architecture changed considerably; leaves unrolled later, the number of green leaves was lower, the internodes lengthened less, and the inflorescence was shorter as a consequence of water deficit. Drought stress decreased the number of fertile florets in the panicle significantly, in the lower clusters of branches in particular. In the cultivar “Puhti”, 57 % of the fertile florets aborted as a consequence of moderate drought stress and 89 % as a result of severe drought stress when compared to well-watered individuals, while in “Virma”, a cultivar of significantly higher yield potential, 80 °lo and 90 % of the fertile florets wilted, respectively. In addition, water deficit caused considerable losses in all the morphological characteristics measured. Further implications of these results for yield formation are discussed.

Highlights

Genome as well as environment determine the progress of development of cereal plants
Neither moderate water deficit nor severe drought stress affected the developmental rate of inflorescence in the cultivars examined when compared to the well watered group
Water deficit considerably affects the architecture of a plant and plant stand, but results concerning the influence of drought stress on the developmental rate are more divergent

Summary

Introduction

Genome as well as environment determine the progress of development of cereal plants. Water deficit is associated with high temperatures a reason why drought stress is commonly noted as hastening ripening and pre-anthesis inflorescence development. Within this context, the question of water stress is of special interest in Finnish growing conditions, as early summer drought (Mukula and Rantanen 1989), occurring exactly during the development of inflorescence, is a recurrent problem in southern and southwestern areas especially. The objectives of the present study were to evaluate the effects of moderate and severe water deficit on 1) the developmental rate of the panicle, 2) the formation and abortion of fertile florets, and 3) the formation of the oat stand and the yield components in two cultivars, “Puhti” and “Virma”, differing in yielding ability

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