How should high-quality cotton seed be planted to produce good seedlings?

At present, most cotton-growing regions in China use nutrient-pot seedling raising. Generally, to evaluate whether cotton seed emergence is good or poor, one looks at the emergence rate and, second, at the seedling survival rate. The reasons for a low emergence rate are: first, in some cotton seed, the proportion of autumn bolls or late-autumn bolls is too large, which lowers the germination rate. The germination rate of seed selected from summer bolls or mid-season flowers is mostly above 80%; second, during cotton seed processing, quality control was not strict, and the proportion of damaged seed exceeded the standard; third, before or after sowing cotton seed, no fungicide disinfection was carried out on the pot soil and the soil covering the pots, or the disinfectant chosen was not the right one; fourth, after sowing this year's cotton seed, the weather remained continuously dry, and many growers who watered insufficiently at sowing had poor emergence; fifth, after sowing, the soil cover was too deep or too shallow; seedlings from too deep a cover are weaker, while those from too shallow a cover emerge with the seed coat still attached or with lifted feet; sixth, after cotton emergence, no pesticide was sprayed in time to protect the leaves, and perfectly good cotton seedlings died from disease. As for the reasons for a low seedling survival rate, some growers report that the seedlings emerged quite well but then died severely. According to my field inspections, first, seedlings died from infection with damping-off, anthracnose, and sudden wilting; such deaths accounted for more than 80% of all seedling deaths; second, fertilizer damage or misuse of pesticides injured the cotton seedlings; third, high temperatures scorched the seedlings. In the survey, no seedling deaths from freezing damage were found.

Generally speaking, superior cotton varieties potentially possess the fine traits of high yield and high quality, and compared with inferior varieties, their emergence rate and seedling survival rate are correspondingly higher, but a superior cotton variety cannot be equated with a high emergence rate and seedling survival rate. In this year's cotton nutrient-pot seedling raising process, the exposed problem of low emergence and seedling survival rates in good-quality cotton shows that some of our farmers' technique of sowing once and achieving full stands in one pass is still not solid enough. For this reason, we must sum up experience and lessons, and in next year's cotton seedling raising work, do a good job at the following points: first, choose superior cotton varieties with high maturity and avoid using cotton seed with poor maturity; second, before sowing, sun the seed for 2~3 days while removing broken seed and immature seed; this can raise the germination rate by 3%~5%; third, change the seedbed every year to prevent residual pathogens in the soil; fourth, spray fungicide to disinfect the seedbed pot soil and the soil covering the pots; fifth, when the cotton seedlings emerge and the two cotyledons are flat and spread, promptly spray pesticides such as Bordeaux mixture, Pu K, and Shileshi to protect the cotton seedlings; sixth, during the seedling raising process, prevent drought damage, waterlogging damage, pesticide damage, fertilizer damage, freezing damage, and high-temperature scorching of seedlings.