Study On The Ornamental Value And Resistan-Ce Of Kaiyuan Mumian In Yunnan

'Kaiyuan Mumian'which belongs to Gossypium Linn,of Malvaceae,derived from Egyptian island cotton.In this study,the ornamental characteristics of'Kaiyuan Mumian'at seeding,flowering and fruit stages were investigated,and the ornamental value of'Kaiyuan Mumian'in the garden was explored,based on the evaluation criteria of ornamental value of woody flowers and the national standard of agronomic traits of cotton.The cold resistance of'Kaiyuan Mumian'was studied by comparing the representative materials of cotton'Shiya 1','Zhongmian 64','Keyin'.Based on cotton production practice,low temperature treatments of 0 0C,4 ? 8 0C for 72 hours were set up respectively and the temperature of 25 ? was used for comparison.Morphological changes were observed and physiological indices including relative conductivity,MDA content,soluble sugar content,SOD activity were measured for these materials at their seedling stage regarding to cold hardiness.Deal with in 0 ? and 0 h,24 h,48 h and restored at room temperature for 48 h as supplementary experiment,to further explorethe cold temperature and duration of'Kaiyuan Mumian'.In addition,the performance of cold resistance of Kuaiyuan Mumian in the natural environment of Kunming was observed.Meanwhile,the Verticillium Wilt Resistance of 'Kaiyuan Mumian'at seedling stage was identified by inoculation,and its comprehensive resistance to disease was evaluated in natural environment.The results of this resistance study could serve as reference for the cultivation and maintenance of 'Kaiyuan Mumian'as potential ornamental plant in the open air.The main results were as follows:1.'Kaiyuan Mumian'has higher ornamental value:it is a compact plant-type at seeding stage,the tall and straight trunk,palmately lobed and large leaves,large and umbrella-shaped crowns.The shoots and leaves flourish and it can be used as potted plants or street trees.It can be used as Woody flowering plants because of its beautiful posture,luxuriant and large flowers,transparent petals,long flowering period and flower color varied.'Kaiyuan Mumian' has tree full cotton bolls,cotton bolls are peculiar in shape and texture.It was beautiful and can be used as plants with ornamental fruits.And the main ornamental periods are flowering and fruiting.2.Cold resistance:The seedlings of the four materials could not tolerate the low temperature stress of 0 ? for 72 hours,and could tolerate the low temperature of 0 ?for 48 hours and 4? for 72 hours.Low temperature of 8? for 72 hours would not cause irreversible damage to the seedlings of four cotton species.From the changes of relative conductivity,MDA content,soluble sugar content and SOD activity before and after treatment,the cold resistance of 'Kaiyuan Mumian'had no obvious advantage.However,through the performance of 'Kaiyuan Mumian' in the natural environment in winter of Kunming,it can tolerate the intermittent low temperature stress,showing better cold tolerance.3.Quantitative inoculation test showed that'Kaiyuan Mumian'can tolerate Verticillium wilt to some degree,followed by 'Hai7124' which was used as parent in breeding frequently.But in the natural incidence test of potted cotton seedlings,'Kaiyuan Mumian'suffered the least,with complete leaves and has just a few lesions.The infection index in order from low to high was'Kaiyuan Mumian','Shiya l','Hai 7124','Keyin','Zhongmian 64',which indicated that the comprehensive disease resistance of'Kaiyuan Mumian'is better.