Designing a Wheat Ideotype with Increased Sink Capacity

In this investigation, genotypes with branched, tetrastichon (two spikelets per node of the rachis), and normal spikes were used in order to induce changes in sink capacity, while high-yielding domestic and foreign varieties served as donors of other traits. These materials were crossed by the methods of single-, back-, and top crossing and the desirable genotypes were selected by the pedigree method. After 10 years of breeding for the desired ideotype, whose main features had been a highly fertile spike of normal structure, short straw, curved leaves, and reduced tillering, 229 lines were tested in comparative yield trials. Among them, four lines were superior in yield and other traits to the highest yielding standards. Regarding the expected changes in sink capacity, considerable progress was made in spike length, number of grains per spike, number of grains per spikelet, and the weight of grains per spike.