| Abstrakt: |
Spring wheat (Triticum aestivumL.) is a major crop of the northern Great Plains. High temperature stress during the grain‐fill period is a major constraint to increased productivity of spring wheat, particularly in the southern part of the region. The electrolyte leakage or membrane thermostability (MT) test was conducted at anthesis on flag leaves of eight field‐grown genotypes of spring wheat and the results related to the yield of those genotypes grown at three other field locations. Genotypes were derived from two crosses involving parents adapted and unadapted to the region or thermal aspects of the climate. The three field locations represented northern, central, and southern areas of the northern Great Plains with soil classifications of Aeric Calciaquoll, Aeric Calciaquoll, and Typic Haplustoll, respectively. Based on MT values, genotypes were grouped as heat‐tolerant (HT, n= 4) vs. heat‐sensitive (HS, n= 4). The HT and HS genotypes produced similar grain yields at the northern and central locations. However, the HT group of genotypes produced 21% more grain yield (4.28 Mg ha−1) than the HS group (3.55 Mg ha−1) at the southern site, which was considerably warmer during the grain‐fill period than the other two locations. Average temperatures during July were 19.5, 21.7, and 23.4 °C at the northern, central, and southern locations, respectively. Based on results of this study it seems that the MT test is a useful screening procedure for selecting HT genotypes of spring wheat. |
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