Research On Selections Of Planting Stocks And The Technology Of Chemical Control On The Potato Pre-basic Seed Production Under Aeroponics

Aperonics drastically improves the efficiency of the potato pre-basic seed production.Aeroponics automatically controls conditions for potato growth and development and sprays the atomized the nutrient solution to roots surface,which solves the contradictions of oxygen and absorbing nutrient.Compared with traditional methods of substrate culture for pre-basic seed production,aeroponics has a unique advantage.Sichuan is one of the major potato production areas of China,charactered by its all-year round potato production seasons and supply.Potato pre-basic seed can be produced in spring and autumn seasons.The spring crop starts from the cold short day winter and ends in the warm long day summer,whereas the autumn crop from the warm long day summer to cool short day winter.According to the two contrast growing seasons,the present aeroponics still has the potential to further increase the tuber yield and tuber number per plant for pre-basic seed potato by regulating.In necessarily considering the prevailing two contrasting climate characteristics of spring and autumns in Sichuan,the thesis made a further research on some key technologies for potato pre-basic seed production under aeroponics,to optimize the aeroponic technology system and to study the physiological effects.Virus-free hydroponic seedlings of cultivars Favorita,Chuanyu 117,Chuanyu 802 and Mira were used as experimental materials,to study the effects of whole plantlets and apical cuttings on plant growth and yield.In order to make a further research on effects of foliar spray of gibberellins,uniconazole and calcium nitrate on hydroponic seedlings growth,yield and other physiological index,Favorita and Mira were used as the experimental cultivars.The results are shown as below.1.At the early stage of transplanting,the time of apical cuttings complete orGA3n morphogenesis was later than whole plantlets.But apical cuttings own a stronger growth vigor than whole plantlets and the growth vigor of apical cuttings was not worse than whole planlets at the late stage of transplanting.The tuber formation exuberant period of apical cuttings was lagged behind whole plantlets about 5-8 days.While the tuber formation time of apical cuttings was earlier than whole plantlets.2.Compared to whole plantlets,apical cuttings didn't significantly affect the tuber yield of cultivars Favorita,Chuanyu 117 and Chuanyu 802,but significantly increased the tuber yield by 34.4%.3.Foliar application of GA3 had significant promoting effects on the absorption of nutrient elements and plant vegetative growth,significantly increased the content of N,P and K in autumn,and significantly increased plant height,leaf area the number of stolon 's branches,leaf area index dry matter accumulation,root-shoot ratio.Which provide adequate photosynthetic product and material basis for tuber formation and expansion.Foliar application of CN had no significant effects on plant growth.Foliar application of S-3307 had an inhibitory effect on the plant vegetative growth,which significantly reduced plant height,the number of stolon's branches and leaf area index.4.Foliar application of GA3 significantly increased yield by regulating plant vegetative growth.Compared to CK,foliar application of GA3 significantly increased tuber yield per plant by 13.8%?51.1%and tuber number increased by 21.9%?90.3%.Foliar application of CN had no significant effects on tuber yield.Compared to control,foliar application of S-3307 had no significant effects on tuber yield for Favorita and Mira In spring and significantly reduced tuber yield by 44.6%-50.8%for Favorita and Mira in autumn.In conclusion,compared to whole plantlets,apical cuttings had a major advantage on reducing production cost on the basis of obtaining high yield.Therefore,apical cuttings own a strong promotion value on the process of potato virus-free per-basic seed production under aeroponics.Foliar spray of GA3 achieve yield-increasing effect by regulating plant vegetative growth.In autumn,the tuber yield and tuber number per plant with foliar spray of CN plus GA3 were optimal for both cultivars Favorita and Mira.While,the difference of tuber yield and tuber number per plant between foliar spray of CN plus GA3 and foliar spray of GA3 alone was not significant.In pring,tuber yield and tuber number of foliar spray of GA3 alone were significant higher than the foliar spray GA3 plus CN for Favorita.For Mira,tuber yield and tuber number per plant of foliar spray GA3 plus CN were optimal,while the difference of tuber yield and tuber number per plant between plant of foliar spray GA3 plus CN and plant of foliar spray GA3 alone was not significant.Therefore,foliar spray of GA3 alone or foliar spray of GA3 plus CN can be considered on the process.