Evaluation of winter wheat as a source of high yield potential for the breeding of spring wheat

Abstract

Grain yield components of high yielding European winter wheat varieties and of the best spring varieties grown in Israel were compared and their growth was analyzed. F₁- and F₂-populations of crosses between winter and spring varieties were tested. Under conditions in which winter wheat attained its normal kernel size which was similar to that of the spring varieties tested, it markedly outyielded spring wheat by means of its greater number of spikelets per spike. This advantage was also expressed in the F₂-populations and, was apparently, not linked with cold requirement. Winter wheat had a longer growing period and a greater leaf-area but a lower net assimilation rate than spring wheat. The higher total dry matter yield of winter wheat was owing to its longer growing period. The higher grain yield, however, was induced by a higher ratio of grain to total dry matter accumulated during the period of kernel development. The inheritance of several characters is discussed and it is concluded that winter wheat should be able to contribute to an increase in yield of progenies of its crosses with spring wheat.