藁城县大同公社东邑生产大队1960年开始种植“石短5号”棉花,当时田间纯度在85%以上,绒长在32—34mm、衣分在34—35之间。群众认为这个品种植株紧凑适于密植,管理省工,产量高,品质好,售价高,是个较好的良种。但由于对选种留种工作重视不够,致使种子纯度逐年下降,退化严重,产量、品质也随之降低。据1963年调查,田间纯度已降至50%左右,绒长缩短2—4mm, Tancheng County Datong commune Dongyi production brigade began planting “short stone No. 5” cotton in 1960, when the field purity of 85% or more, velvet long in the 32-34mm, clothing points between 34-35. The masses believe that this species is compact and suitable for close planting, management and labor, high yield, good quality, high price, is a better seed. However, due to lack of attention to the selection of species to stay, resulting in decreased purity of the seed year after year, serious degradation, yield, quality also will be reduced. According to the 1963 survey, the field purity has dropped to about 50%, shortening the length of 2-4mm,