Evaluation of Grain Filling Rate and Duration in Bread and Durum Wheat, under Heat Stress after Anthesis

Abstract

Bread and durum wheat genotypes were submitted to heat stress during the grain filling period, and relationships between grain weight and accumulated time from anthesis until maturity, using days after anthesis and growing degree days, were described by cubic polynomials. Maximum grain weight and the duration and rate of grain filling were estimated from the fitted curves. It was found that bread and durum wheat exposure to high temperatures significantly decreased grain weight and hastens physiological maturity (shortening the grain filling period). High temperatures significantly affected the rate (on a growing degree day basis) and duration (on Julian day units) of grain filling. The grain filling rate, on a thermal time basis, was positively associated with the final grain weight and the estimated maximum grain weight. The duration of grain filling does not appear to be a limiting factor for genotype grain weight stability, being mainly fixed by temperature. Grain weight of the controlled plants was positively correlated with the final and maximum grain weight of heat stressed plants. It was concluded that a high grain filling rate and a high potential grain weight are major traits that can be useful to improve heat tolerance of Triticum under Mediterranean environments.

Response of floret fertility and individual grain weight of wheat to high temperature stress: sensitive stages and thresholds for temperature and duration

“…Our earlier research with wheat showed that HT stress did not have large impact on the rate of grain filling, but it significantly decreased the grain filling duration, leading to smaller individual grain weights (Prasad et al 2008b). High temperature accelerates the rate of grain filling, but shortens grain filling duration (Dias and Lidon 2009). For every 1 C above the optimal growing temperature of 15À20 C, the duration of grain filling was estimated to be reduced by 2.8 days in wheat (Streck 2005).…”

“…In addition, morphological characters such as stigma hyperplasia and stamen hypoplasia can result in failure of pollination (contact of pollen with stigma) and the fertilisation process (Takeoka et al 1991). Changes in composition and concentrations of carbohydrates (Jain et al 2007), lipids and reactive oxygen species (Djanaguiraman et al 2013a(Djanaguiraman et al , 2013b(Djanaguiraman et al , 2014 in pollen gains result in pollen sterility. Additional research is required to test these principles in wheat.…”

“…Merr. ; Djanaguiraman et al 2013aDjanaguiraman et al , 2013b, resulting in lower seed yield. High temperature stress during pre-anthesis (microsporogenesis) causes poor pollen viability and fewer pollen grains, resulting in lower seed set in rice and sorghum (Prasad et al 2006a(Prasad et al , 2008a.…”

“…Similarly, maximum temperature above 31 C for a 5 day period ending at anthesis decreased seed set, leading to lower number of seeds per spike in wheat (Wheeler et al 1996). High temperature stress during reproductive development altered pollen morphology and resulted in an abnormal exine wall, degeneration of tapetum cells and membrane damage, leading to decreased seed set in soybean (Djanaguiraman et al 2013a(Djanaguiraman et al , 2013b and sorghum (Djanaguiraman et al 2014). Anatomical evidence explaining reasons for failure of pollen germination under HT stress in wheat are not clearly documented.…”

Impact of Various Irrigation Levels on Growth, Yield and Water Use Efficiency of Wheat at Variable Temperatures

“…), harvest index (HI) and WUE were also statistically high under normal field conditions (T 1 ) than controlled condition's (T 2 ). Heat stress results in severe kernel abortion (Wardlaw and Wrigley, 1994) and its improper maturation (Hays et al, 2007) and higher temperature hindered food translocation because of osmoregulation effect under heat stress (Plaut et al, 2004), reduced grain filling period (Dias and Lidon, 2009), retarding endospermic cells proliferation, so ultimately declined in grain weight (Feng et al, 2000) was reported. Fertile tillers and harvest index under different irrigation levels were statistically significant and gradually decreasing trend was observed as irrigation levels decreased.…”