选田优良小麦品种是主要的增产措施,所用种子要力求纯正,纯正的种子能最大限度地保持优良品种的种性(遗传特异性),种子纯度(遗传一致性)要符合规定的要求,这样才能充分发挥优良品种的增产作用。品种混杂则会降低增产作用,品种混杂指机械地混入其他品种(也包括其他作物)种子或杂入本品种退化了的种子,所谓混杂退化。由于杂入种子长出的植株农艺性状低下,穗小穗少、粒小秕瘦,或者个高秆软,或感染病虫,或不耐 Election excellent wheat varieties is the main measures to increase production, the seeds used to strive for pure, pure seeds to maximize the species to maintain good varieties (genetic specificity), seed purity (genetic consistency) to meet the requirements of the provisions of In order to give full play to the production of superior varieties. Mixed varieties will reduce the role of yield increase, mixed species refers to the mechanical mixed with other varieties (including other crops) seeds or miscellaneous varieties of the degenerated seeds, the so-called hybrid degeneration. As the miscellaneous seeds of plants grow agronomic traits, spikelets spike less, small slender, or a tall stalk soft, or infected with pests or intolerance