Agronomic Response of Three Height Classes of Spring Wheat, Triticum aestivum L., Compared at Different Yield Levels¹

Abstract

‘Centana’ (Cnt) plus short, medium, and tall selections of Norm 10/Brevor, 14//6*Centana were grown in yield nurseries at 22 Montana locations in 1969 and 17 locations in 1970. The study was designed to determine the magnitude of the genotype by environment interactions of the three height classes when grown under Montana conditions. Such information is needed to help define the limitations, if any, of semidwarf spring wheats. Agronomic data from each location are reported within one of six yield levels, each level separated by 673 kg/ha (10 bu/acre), with the location average yield determining the yield level assigned. Medium Cnt had the highest grain yield at all yield levels, except at one location which yielded less than 1352 kg/ha (20 bu/acre). Short Cnt was consistently lowest of the four entries in grain yield and test weight. Short Cnt increased only 29.3% in plant height from the second to sixth yield level, whereas other varieties increased more than 48%. The grain:straw ratio was highest for short Cnt and lowest for Centana and tall Cnt. The data suggest that breeding efforts for Montana spring wheat should emphasize the development of single gene dwarfs (semidwarfs), and that 2‐gene dwarfs (short selections) generally should be avoided.

Effects of pre-anthesis moisture stress on floret sterility in some semi-dwarf and conventional height spring wheat cultivars

“…At the highest level of stress (7-d watering intervals), all the semi-dwarf cultivars had significantly higher (P ≤ 0.01) levels of floret sterility compared with the tall cultivars. This observation is consistent with those of Laing and Fisher (1977) and McNeal et al (1972) who found that shorter-strawed wheat cultivars yielded less than standard-height cultivars when moisture was limited. Of the cultivars tested, Biggar and Cutler, which were among the cultivars with the lowest sterile floret frequencies under well-watered condition, appeared to be the most sensitive to moisture deficit.…”

“…However, there are also reports that semi-dwarf cultivars are more susceptible to drought and high temperature stress (McNeal et al 1972;Laing and Fisher 1977).…”

Impact of Growth Habit and Architecture Genes on Adaptation and Performance of Bread Wheat

“…Semidwarf lines containing Rht-D1b were discovered to have superior yield as compared to standard height lines. Moreover, McNeal et al [78] observed that semidwarf wheat lines containing either Rht-B1b or Rht-D1b outyielded tall lines in Montana, except in very low yield potential environments where tall lines were superior. From these results, it can be concluded that when opting for high yield potential under normal or high input growing conditions, Rht-B1b and Rht-D1b genotypes are the best, but when planting in hot and dry (low yielding) environments, Rht8 genotypes should be selected for.…”

Inheritance of test weight and kernel weight in eight durum wheat crosses

“…However, reduced kernel size and/or low test weight has been a problem in semidwarf compared with conventional (tall) height genotypes. This has been documented in both durum wheat (Joppa 1973;Gale et al 1981;McClung et al 1986) and common wheat (McNeal et al 1972;Knott 1986;Nizam Uddin and Marshall 1989;Butler et al 2005), although, a cross studied by Busch and Chamberlain (1981) did not follow this pattern. Lebsock and Amaya (1969) also found a positive correlation between kernel size and plant height in lines derived from crosses involving non-dwarf durum genotypes of varying height.…”