Response of Oats to Water Deficit. II. Growth and Yield Characteristics1

Abstract

AbstractLittle information is available on the response of spring oats (Avena sativa L.) to periodic water deficits experienced at different growth stages. Knowledge concerning the manner in which oats responds to water stress is needed to aid in water management of the crop. The primary objective of this study was to determine the effect of a 9 to 11‐day water stress period imposed under a field environment upon the growth and yield components of spring oats (cultivar ‘Jaycee’). The crop was grown on pachic udic haploborolls soil (Lismore silty clay loam) in large pots buried in the field under a natural environment. The water stress periods were timed to occur during the boot stage and the anthesis through early grain formation stage (separately and in combination). Water stress at either stage decreased plant height and the number of florets per panicle. Plants stressed at anthesis through early grain formation had significantly more floret sterility and a fewer number of heads at maturity. Water deficits at all stages caused a marked decline in the yield of straw, tops without panicles, panicles, kernels, and dehulled kernels. Stress at the booting and the anthesis through grain filling depressed kernel yield 20% and 58%, respectively, whereas the combined stress reduced kernel yield 67%. Plants growing under soil water stress conditions appeared to root to a greater depth. On rewatering, the stressed plants, particularly those stressed in the boot stage, showed accelerated growth and profuse tillering. The results indicate that oats are more sensitive to soil water deficits which occur during the anthesis through early grain formation stage than during the boot stage. Therefore, cultural practices and water management should be so implemented to avoid soil water stress during the anthesis through early stage of grain formation.