Studies On Seedling Quality And Growing Effect Of Different Raising Seedling Manners In Cotton

This experiment was carried out in 2001-2002, at Nanjing Agriculture University. The cotton seedling quality and growing effect of seedling raising manners were conducted with "Sumian 12". The main results showed:50-hole and 72-hole treatments had a high rate of seedling emergence and a high planting percent after transplanting. In the nursery stage and after transplanting the accumulation showed that the plant height, the number of leaf, the length and number of the root, the dry weight and the fresh weight of 50-hole and 72-hole treatments were more than or similar to CK and the other treatments. Before and after transplanting, the 50-hole treatment had more root vigor, root bleeding sap, the ratio of the root to overall of the dry matter, dry weight of per stem length, content of chlorophyll and carotenoid, the activity of SOD, POD, and CAT, content of N, P, K. than CK, but the ratio of chla to chlb was lower than CK. 72-hole treatment had similar results to CK. After transplanting, 50-hole and 72-hole treatments showed higher seedling quality than CK & 128-hole treatment.These treatments with plastic pot had same growth period duration to CK. In the middle stage of the growth, the 50-hole treatment had a higher LAI, net photosynthetic, dry weight, N, P, K content than CK, but 72-hole and the 128-hole treatments were lower or similar to CK. These treatments with plastic pot had obvious advantages in the weight of seed cotton, the percent of the bolls before hot days and during hot days, but the lint percentage, the seed cotton economic coefficient was similar to CK. The 50-hole and 72-hole treatments had more yield of lint cotton than CK; the 128-hole was similar to CK.The rate of seedling emergence and planting percent after transplanting of the reed-tube treatment was lower than CK. It delayed the growth about lOdays, but it growing faster in the later growth period, it had more total bolls and the percent of the boll of autumn.About the experiment of changing the fertilizer in the nutrient soil, it showed that the seedling quality of the treatment increased P and K but N was better than CK.About the double-stem treatment of getting rid of the sprout keep the two seed leaves when 2.51eaves, the treatment transplanting two weeks later got better seedling quality to CK, the treatment transplanting in 31eaves and getting rid of the sprout keep the two seed leaves two weeks later got the same result. And showed growing better in the field, but delayed the growth period duration 7~8days. The double-stem treatments all had more percent of hot days boll than CK.