The effect of temperature stress on grain development in wheat

Abstract

Experiments were conducted in controlled environments to determine the effects of high temperatures on grain development and yield in wheat. Two Australian and three Indian cultivars of wheat were exposed, from a week after anthesis until maturity, to "day" temperatures of 25, 28, and 3l°C, and "night" temperatures of 9 and 12°C. There was a mean reduction in yield of 16%' for the 6° rise in day temperature, but the cultivars did not differ significantly in their response to these temperatures. There were no significant effects of night temperature on grain weight, but stem weight was less at 12°C. Senescence was hastened only slightly by high day temperature, and there were no differential effects between cultivars in this respect.In a subsidiary experiment one Indian and five Australian cultivars were subjected to three day-night temperature regimes (24/19°, 27/22°, and 30/25°C). Highly significant but complex interactions were established between temperature regime and cultivar. A growth analysis for the Australian cultivars Ridley and Diadem indicated that the developing grain of Ridley had a greater capacity for growth than that of Diadem from the earliest stage. This, together with the confirmation of grain size as a very stable characteristic for all the varieties, points to the developmental and synthetic activity of the grain as an important determinant of grain yield. The relevance of this study to the production of wheat in India is briefly discussed.

Simulating winter wheat spike development and growth

“…Development of floret parts ceases by anthesis, if not before (McMaster, 1991). Asana and Williams (1965) found that chaff weight did not increase after 12 days past anthesis (about 385 GDD).…”

“…With 1 phyllochron period retained for internode elongation, the peduncle completes elongation at the onset of anthesis. Although some data suggest that peduncle elongation occurs into early grain-filling (Asana and Williams, 1965;Rawson and Evans, 1971;McMaster, 1991), SPIKEGRO assumes the peduncle completes elongation at anthesis. Peduncle elongation is simulated the same as all internodes in SHOOTGRO.…”

Climate trends and impacts on crop production in the Koshi River basin of Nepal

“…Experimental studies on several wheat cultivators indicate an optimum mean temperature range of 17-23°C (Porter and Gawith 1999). Similarly, the optimum maximum and minimum temperatures for wheat are around 24 and 19°C, respectively (Asana and Williams 1965;Prasad et al 2008). In the study region, the growing season maximum, minimum and mean temperatures are above the threshold of 20, 10 and 14°C in the area below 1,600, 1,500 and 1,700 m amsl, respectively.…”

Phenology, Growth and Yield of Three Wheat (Triticum aestivum L.) Varieties as Affected by High Temperature Stress

“…The performance of different genotypes under stress may be observed by calculating RP% (Asana and Williams, 1965) and HSI (Fischer and Maurer, 1978). also reported genotypic variation in RP% of sensitive and tolerant genotypes, and a higher RP% indicated that the genotype was tolerant to stress.…”

“…To obtain the actual yield of all varieties, grain yield weight was adjusted at 12% moisture by the following equation (Hellevang, 1995): Heat tolerant data of relative performance (%) and heat susceptibility index were calculated by following equations. Relative performance (RP%) for yield was calculated as described by Asana and Williams (1965) If HSI < 0.5, the crop is highly tolerant to high temperature stress, if HSI > 0.5 < l.0, it is moderately tolerant, and if HSI > 1.0, it is susceptible to high temperature stress.…”