Nitrogen Utilization Charateristics Of Different Genotypic Cotton And Its Growth And Physiological Characteristics

The field experiment was conducted at the Experiment Station of Yangzhou University during 2008 to 2009 with yumian 1, simian 3, Kemian 6, Siza 3, xuza 3, xu 9154, suza 3 and Sumian 9 as experimental materials, to study the nitrogen utilization charateristics of different genotypic cotton, the growth characteristics and physiological mechanisms of different nitrogen use efficiency cotton. To explore the influences of nitrogen and potassium fertilizer on the nitrogen use efficiency. The purposes of these study was to provide theoretical basis of accurate fertilization application for cotton production. The main results were as follows:1. The nitrogen use efficiency for seed cotton production (NUEsp) and the nitrogen recovery efficiency (RE) of different genotypic cotton were different. According to NUEsp and RE,8 different genotypic cottons may be divided into 4 types. NUEsp and RE of Kemian 6 were highest; RE of Simian 3 and Xuza 3 were lower, but its NUEsp was higher; Siza 3 and Suza 3 were contrary to Simian 3 and Xuza 3; RE and NUEsp of Sumian 9, Xu 9154 and Yumian 1 were lowest. Kemian 6, Simian 3, Siza 3 and Sumian 9 were typical cultivars of the four types. Their growth and development characteristics further showed:The plant height of Kemian 6 was highest. The number of fruit branches, the total amount of fruit nodes, the total boll number and setting boll ratio of Kemian 6 were reasonable. Its vegetative growth and reproductive growth were balance, the dry weight ratio of vegetative organs and reproductive organs was 1.02. But those indexes above of Sumian 9 were lowest or inappropriate. The growth and development indexes of Simian 3 and Siza 3 were between the indexes of the cultivar Kemian 6 and Sumian 9.From flowering period to boll opening, the physiological characteristics of 4 typical varieties showed that the proportion of fertilizer uptake for Kemian 6 was largest; its Fruit branch vector, total content of chlorophyll, diameter and number of Vessel and Screen, total soluble sugar content, sucrose invertase, sucrose synthase(SS) and soluble protein content were highest, but its peroxidase(POD) activity was lowesr. Those physiological indexes of sumian 9 were lowest, but its peroxidase(POD) activity was highest; The physiological characteristics of cultivar simian 3 and siza3 were between the indexes of kemian 6 and sumian 9. But the malondialdehyde(MDA) content of simian 3 was highest.2. There was significantly negative correlations between nitrogen fertilization and NUEsp(r=-0.9705*). there were parabolic relationship between potassium fertilization and NUEsp; Higher or lower Potassium fertilizer reduced NUEsp. Such relationship existed between the nitrogen fertilizer and the RE. When the nitrogen fertilization was 17kg/666.7m2, the RE was highest. The increasing of potassium fertilization was help in the improvement of RE, but with further increasing of potassium fertilization, the increasing trend of RE slowed down.3. Nitrogen fertilizer and potassium fertilizer had different effects on the yield, quality and the growth of the cultivars. when nitrogen fertilizer and potassium fertilizer application were 19.5 and 40.2kg/666.7m2 respectively, the lint yield of the high NUEsp and high RE varieties (kemian 6) was highest. Excessive application of nitrogen fertilizer was not good to the improvement of fiber quality, the increase of the potassium fertilizer application was benefit to the improvement of fiber quality. Potassium fertilizer could increase the boll number and the boll setting ratio significantly. there were significantly positive correlations between NUEsp and lint yield, the number of fruit branches, the boll number, setting boll ratio and reproductive organs dry weight ratio.