Yield and quality response of spring wheat cultivars to post anthesis high temperature

[摘要] ENGLISH ABSTRACT: Knowledge of the growth, yield and quality response of spring wheat cultivars to hightemperatures is important to minimise variation that often exists in yield and breadbakingquality of wheat produced in warmer regions. To achieve this, four SouthAfrican spring wheat cultivars Kariega, Palmiet, SST 55 and SST 57 were grownunder controlled conditions at the University of Stellenbosch during 1998 attemperature regimes of 15/10, 20/15, 25/20 and 30/25°C during grain filling. Fromseeding till anthesis, plants were grown at a temperature of 15/10°C. In this study,.the highest temperature regime of 30/25°C affected all parameters tested, while atlower temperature regimes cultivars responded differently. The 30/25°C temperatureregime caused premature senescence of the leaf area which was attributed to adecrease in relative leaf water content. Increased senescence of leaves at thistemperature regime, reduced photosynthesis during grain filling, with the result thatshriveled kernels with a lower mass kernel -1 were produced and yield plant -1 wasreduced by almost 50% compared to that of the control (15/100 C). Other yieldcomponents such as kernels ear -1 were less reduced and Kariega was less affectedin comparison with the other cultivars.High temperature regimes of 30/25°C during grain filling resulted in increased flourprotein content. Mixogram peak heights increased as post-anthesis temperatureregimes increased, while Palmiet also showed an increase in dough developmenttime with increasing temperatures. At the highest temperature regime (30/25°C), therespective dough development times for SST 55 and SST 57 were well below theoptimum mixing time of 2.5 to 3 minutes set by the baking industry, while themixograph band widths of Kariega were the narrowest at all temperature regimestested. This tendency indicated good water absorption properties. These results indicate that quality parameters of Kariega and Palmiet are less sensitive to highpost-anthesis temperatures in comparison with SST 55 and SST 57. In general, it isconcluded that although this study showed small differences between cultivars,Kariega was consistently different from other cultivars, indicating possible adaptationto hotter environments. However, more cultivars need to be screened beforerecommendations for such areas can be made.

[发布机构] Stellenbosch University