Anther Culture Studies Of Solanum Tuberosum: Varieties Selection And Procedure

Anther culture has critical significance for genetic research and breeding of potato (Solanum tuberosum L.).Anther-derived dihaploid is capable of simplifying the genetic analysis and improving the efficiency of selection in breeding,and can be taken as bridge to introduce useful genes from relative wild diploid genera.However,there was rare successful report on potato anther cultrue in the southwest region of China.Based on a serial studies on varities selection,anther picking,sterilization,controlling of browing,etc., characters during culturing of anthers from different varieties and effects of hormones (plant growth regulaters) and their combinations were studied.The main results and conclusions are as follows:1) Investigation data of budding,flowering,seeding in 4 years,5 seasons indicate that:â‘ Both variety(line) proportions of budding,flowering were very low,the proportions in spring were significantly higher than autumn.â‘¡There were significant differences in budding,flowering rate among varieties;11 varieties,budding and flowering stably,were selected from 117 varieties as materials for further anther culture studies.Observation of inflorescence,meiosis and microspore result that:â‘ Developing stages of microspore can be estimated by color and length of bud and anther.â‘¡The correspondence between morphologic and development stage were affected by varieties and seasons.â‘¢Bud and anther characters of tested varieties at stage suitable for anther culture were revealed.2) Studies on relative factors of anther culture were conducted.The results show that:â‘ Due to arising of temperature,there were significant differences among seasons and periods of anthers collection;Anther from plants in spring is better than autumn,and the early differentiated anther had higher potential for culture.â‘¡The suitable method for bud sterilizing is treated by 70%clcohol followed by mercuric chloride,mercuric chloride might be harmful to anther for further culture.â‘¢There was no significant effect of low temperature pretreatment was observed;and high-temperature preincobation promoted the formation of calli.â‘£AgNO₃ reduced browning rate and increased calli rate of culturing anther variety-independently.PVP reduced browning rate,but reduced calli rate of anther. Transfering of anther resulted in increased browning rate and reduced calli rate of anther.⑤Sucrose,instead of lactose,is suitable for formation of callus,variety-independently. There should be relationship between callus initiation and carbohydrate metabolism,and both differ in genetic basis among varieties tested.â‘¥There were significant effects of tuber extract on browning and callus rate of anther;and the effects depend on variety of tuber used.3) Anthers of 11 varieties were compared by cultured on the same medium,the results show that:â‘ There were significant differences of browning rate,browning trend,bulge rate,calli rate among varieties.Highest calli rate from N5-09 was 7.17%,while there was no callus formed on other 7 varieties tested.â‘¡Significant relationship were revealed between anther browning rate of early culture stage and calli rate by correlation analysis.â‘¢11 varieties tested could be classified into 3 groups by cluster analysis.Varieties belonging to the same group were no significant difference in culture,should be genetical similar;while those from different groups differed significantly in culture.â‘£Varieties of groupâ… performed similar in culture,had different reaction with different media,suggested that the genetic basis of anther culture capacity might be complex.4) Media complemented with different auxin and cytokinin concentrations and combinations were used for anther culture of 3 varieties.The results show that:â‘ Significant differences were revealed among media.â‘¡Generally,higher ratio of auxin/cytokinin was advantage for callus formation,on the contrary lower auxin/cytokinin ratio was disadvantage.â‘¢The highest calli rate was gained at medium complemented whth 2.0 mg/L 2,4-D+0.5 mg/L KT.Reducing the concentration of 2,4-D,increasing the concentration of KT,substitution 2,4-D with NAA reduced calli rate of anther.TDZ,as substitute of 2,4-D,resulted in no callus formation for all 3 varieties.â‘£Calli produced by anther were proved to be low differential capacity;which suggested that callusadventitious shoots might not be an ideal approach for anther plant regeneration.5) It is suggested that the main restrictions of potato anther culture in the southwest region of China be:â‘ Ecological environments,light length and temperature,restriction ecological type of varieties by reducing budding and flowering of plant.â‘¡The genetic basis of anther culture capacity should be complex and might be related to genetic basis of ecological response.â‘¢Pollen mother cells'meiosis was abnormity and lead to lower potential for anther culture.â‘£Thus,under the ecological environments of Yaan,selection of the culture conditions for potato anther culture ware more difficult.Proposals for improving anther culture in southwestern China were discussed.