Effect of Semidwarf Stature, Head Number, and Kernel Number on Grain Yield in Barley in Morocco

The purpose of this research was to obtain information on the contribution of semidwarf stature, high head number, and high kernel number to increasing grain yield in barley (Hordeum vulgare L.) in Morocco. The three traits were selected because of their potential to enhance grain yield. Six populations, two for each character, were developed by crossing the Moroccan cultivar ‘Arig 8’ to six Minnesota lines and then backcrossing the Fl's to Arig 8. This was followed by selection in the BC₁F₃ generation in St. Paul, MN, and in the BC₁F₄ generation in Morocco. Data were collected in Morocco from yield trials conducted in four field environments in 1981–1982 and 1982–1983. The procedure of introducing yield-related traits via backcrossing to an adapted cultivar gave progenies that were superior to the relatively high-yielding local cultivar, Arig 8. Eleven lines from the head number populations and eleven from the kernel number populations produced significantly higher grain yields than Arig 8. Two semidwarf lines were superior in yield to Arig 8. Semidwarf selections had increased lodging resistance and harvest indices, but were relatively taller in Morocco than in Minnesota. Generally, the highest yielding lines had modestly higher head number (differences not significant) or higher kernel number than Arig coupled with high kernel weight. Kernel weight was higher or near the high level of Arig 8 in most of the highest yielding lines. We could not determine whether the transgressive segregation for grain yield resulted from breeding for the three characters in question or from the reassortment of other genes from Arig 8 and the Minnesota parents. In this breeding effort the major limiting factor appeared to be an inability to consistently obtain uniform yield trials, and not available germplasm.