Biological And Physiological-biochemical Characteristics Of High-yield Insect-resistant Transgenic Bt Cotton "SCRC21"

Cotton bollworm was the primary pests of the yellow river cotton aera in the country.The1990s cotton bollorm continued outbreaked in the contton aera of the yellow river, whichmade large economic loss, cotton production declined sharply and with the internationalcompetition aggravating, production not only required the new varieties insect-resistant, highyield, superior quality, but also good comprehensive characteristic, better resistance, yieldstability, easy management and so on, which put forward the better requirements on cottonbreeding. Faced the outstanding problems on production, during this situation, based ontheoretical basis about the research at home and abroad of insect-resistant transgeniccotton,used domestic insect-resistant Bt transgenic cotton germplasm for source resistance toresearch about insect-resistant breeding, finally seed selected having our own independentintellectual property rights, good comprehensive characteristic the SCRC21of conventionalinsect-resistant contton. This paper introduced the breeding process about the SCRC21ofinsect-resistant Bt transgenic cotton, the performance of production quality resistance,supporting cultivation techniques of high yield and high efficiency, and deep researched theBiological characteristics and physiological characteristis about SCRC21. Making fourdifferent type of insect-resistant transgenic cotton for the materials, which large areapopularized on production, deeply researched the Biological characteristics and physiologicalcharacteristics of high production and high efficiency about the SCRC21of insect-resistant Bttransgenic cotton. The results were bellow:1Both the nutrition growth speed and dry weight per plant of SCRC21were higherduring the early stage. The dry weight per plant of SCRC21was2.2%higher than that ofSCRC15,59.0%and62.0%higher than that of CCRI41and99B respectively.2The reproductive growth speed of SCRC21speeded up after blooming, and bolls wereset up rapidly. The full growth period of SCRC21was3-5d shorter than that of CCRI41and99B. SCRC21had a larger boll size, as well as higher lint percentage and more bolls per plantthan that of other varieties. Therefore the yield components of SCRC21were improvedsimultaneously. SCRC21could set up source rapidly first and then enlarge sink and hadabundant source with broad sink finally, and also early mature without premature senescence. 3The results indicated that the nutrition growth harmonized with reproductive growthwell on SCRC21. These biological characters of SCRC21establish a foundation for higherand it’s stable yield and wide adaptability.4Blade had higher chlorophyll contents. Chlorophyll contents was the important symbolabout length of time of blade function, at the same time reflected the photosynthetic unitnumber and Nitrogen level in the body of unit leaf area, and measured the ability strong orweak and aging degree of plant photosynthesis. Research confirmed that in the later stage thevarieties which had higher chlorophyll contents could make more economic yield. Thisresearch showed that compared with other varieties SCRC21had higher chlorophyll contents,and until booming period still higher than that of other three varieties, which explained thatSCRC21had better photosynthetic assimilation ability. And blade had longer function period,which favorable for dry matter to accumulate, finally made higher biological yield andeconomic yield.5Blade had higher starch contents and soluble protein contents. Both the starchcontents and the soluble protein contents were significantly higher than CCRI41and99B atseedling stage, squaring stage and early flowering stage, and it has the fast rise, large amount,last long time since squaring stage of the soluble state sugar content, which coincided with thevarieties about rapid growth, big accumulation of dry material before flowering stage, laudedthe material base for concentrating flowering and into the bell. And after flowering untilbooming period still maintained higher carbon and nitrogen metabolic level, thus guaranteedthe supplying of enough photosynthesis product, which made them into the bell persistently,intensively, abundantly and upper central lower uniformly.6Blade had higher antioxidant enzymes activity. Higher activity played more importantrole in preventing membrane lipid peroxidation, reducing membrane damage and plant aging.This study showed that SOD activity was higher than similar varieties CCRI41and99B inmost of the time, among them, at bloom stage and exuberant bell stage, was higher thanhybrid cotton SCRC15, which explained that SCRC21had better resistance than the othervarieties. POD was important protective enzyme in defensing reactive oxygen or otherperoxide free radicals which damaged to cells. In certain stage of blade growth, POD hadhigher activity, the stronger anti-aging ability of blade. After blooming period of SCRC21,POD rised obviously, which reflected that SCRC21had the physiological characteristics ofstronger reactive oxygen resistance in the later growth. MDA was final breakdown productsof membrane lipid peroxidation, which damaged to cell membrane, MDA contents reflectedthe damage degree of cell membrane, which was one of index commonly used to membrane lipid peroxidation. This research showed that SCRC21had lower MDA contents than theother varieties in the middle and early period of growth. Which coincided with that SCRC21had higher antioxidant enzymes activity, better resistance performance in field production.7Hormonal metabolic substances of blade was coordination. Hormone regulated growthand development of plant in system way. Study speculated that production advantage ofhybrid, especially on boll number and boll weight, was probable relevant with the content ofIAA and ABA and considered that ginned cotton was related with IAA content significantly.This research result showed that hybrid cotton SCRC15had higher IAA contents than theother three varieties, which consistented to projections. SCRC21had the similar growthcharacteristics to hybrid cotton, early period growed quickly, dry matter accumulated largely,which insepared with the higher IAA contents before booming period.