Influence of drought stress after anthesis on growth and yield of wheat cultivars from Ethiopia

[摘要] English: The situation in Ethiopia, where post anthesis water stress caused by early cessationof rainfall is a serious constraint to crop production, supplied the rationale to study theperformances of two Ethiopian bread wheat cultivars under induced post-anthesiswater deficit stress. The study also involved the investigation of the possible role ofComCat in circumventing the effects of the stress condition as well as its effects onpre- and post-anthesis growth and development of the cultivars, including its effects onthe protein and starch contents in seed. The two Ethiopian bread wheat cultivars(HAR-2508 and ET-13) were grown under glass house conditions and subject to postanthesis water deficit stress while the effects of treatment with ComCat, a biocatalystfrom plant origin, were followed during the vegetative growth phase as well as atharvest.Observations made through the different growth stages indicated that the two cultivarswere growing at more or less similar rates during the early growth stages after whichsignificant differences between cultivars were observed during later growth stages withET-13 being superior to HAR-2508 in terms of most of the vegetative as well as yieldparameters under both non-water stress and stress conditions, including the mostimportant yield parameter, i.e. grain yield per unit area. The cultivars also showedsignificant differences in their grain protein and starch contents. The cultivar ET-13was superior to HAR-2508 in seed starch content expressed as g g-1FW while thelatter was superior in terms of starch content expressed on a mg seed basis. On theother hand, seeds of HAR-2508 were superior to those of ET-13 in total proteincontent (expressed on both a mg g-1and mg seed-1 basis) as well as in water solubleprotein content (mg seed),Moreover, the water stress condition induced at growth stage 60 caused significantreductions in vegetative growth and yield components in both cultivars, with thereductions being more pronounced in the cultivar ET-13. On the other hand, theComCat treatments at different growth stages tended to enhance root developmentand tended to circumvent the negative effects the water stress treatment had on thevegetative growth of the plants. However, ComCat had no significant enhancing effecton the grain yield per unit area, which was in contrast to what was observed in fieldtrials on both wheat and maize as well as to claims made by the manufacturers of thecompound (Agraforum, Germany). Lack of a significant effect of ComCat on grain yieldunder glass house conditions was presumed to be related to the restriction imposedon the growth of roots of the plants by the small sized pots in which the plants grew.The biocatalyst, when applied at early growth stages and particularly at growth stage13, however, significantly increased the total protein content in seeds of waterstressed plants.Finally, based on the observations made in this study and because of its shorter lifecycle, the cultivar HAR-2508 seems to be a better choice to ET-13 in wheat growingareas of Ethiopia where terminal water stress, particularly through early cessation ofrainfall, is prevalent. However, full recommendation of this cultivar to such areasrequire the investigation of its performance under other prevalent limiting factors suchas diseases, weeds and bread making qualities. With regard to the biocatalyst,ComCat, although it showed no significant effect in improving grain yield per unit areaunder glass house conditions, based on the claims of the manufacturers and also onthe findings during field trials (results not shown) as well as its significant effect inenhancing root development and increasing protein content of seeds as observed inthis study, it appears essential to test it further in field trials under Ethiopian conditions.

[发布机构] University of the Free State