Study On Cultivation Of Primocane-fruiting Raspberry Cultivars In Greenhouse

In this experiment,three primocane-fruiting raspberry cultivars or lines,‘Qiuping’,‘Dincum’ and ‘PL-75’,were used as materials to explore effects of different cultivars and different planting times and spacing on plant growth and flowering,phenological periods,fruit properties and evaluation of raspberry,as well as the content of important nutrients in raspberry fruit,including the content of soluble sugar,soluble solids,titratable acid,sugar-acid ratio and Vc,under delayed cultivation conditions of raspberries.It provides a scientific and technical basis to meet the annual supply of fresh fruit through delayed cultivation of primocane-fruiting raspberry,and has important research significance.The main results were as follows:(1)Phenological periods of different raspberry cultivars were observed.Under the conditions of greenhouse cultivation,the fruiting period of the three cultivars was above 67 days,the fruiting period of ‘PL-75’ could reach 75 days,and the ripening period of fruits lasted until the middle of December.Under the condition of open field cultivation,the fruition period of the three cultivars can last from the end of July to the end of October,respectively 85 d,79 d and 97 d.Therefore,it is believed that fresh fruits can be supplied from the end of July to the middle and late December for up to 149 d through the combination of the two cultivation methods.(2)The tree growth,yield and fruit characters of different raspberry varieties were investigated.In the early growth stage of raspberry,‘Qiuping’ grows rapidly,with the longest stem length and the shortest stem length,‘PL-75’.With the growth of raspberry,the growth rate of ‘Dincum’ and ‘PL-75’ was accelerated,while ‘Qiuping’ grew slowly.The results showed that ‘PL-75’ had the best adaptability to the greenhouse environment,with the largest leaf area,the largest branch growth,the strongest stem,the largest plant height,and the highest yield per plant(213.40g)and the highest yield in the community.The output of the plot was successively ‘PL-75’(1067.0 g),‘Qiuping’(712.8 g),and ‘Dincum’(688.8 g).The average single fruit weight of ’PL-75’ cultivar was the highest,with an average of 3.88 g,followed by ‘Qiuping’(3.75 g).The maximum fruit weight of ‘PL-75’ is 7.8 g,which is obviously higher than that of ‘Qiuping’ and ‘Dincum’.The fruit is shiny,the firmness is the strongest,the hardness is the greatest,and the taste is suitable for sweet and sour.(3)The nutritional quality of fruits of different raspberry varieties was compared.The soluble solids content of ‘PL-75’ and ‘Qiuping’ fruits is the same,both 10.3 %,higher than ’Dincum’.The highest soluble sugar content was ‘Qiuping’(4.62%),followed by ‘PL-75’(4.65%)and ‘Dincum’(4.25%).While ‘PL-75’ has the lowest titratable acid content and the highest sugar acid ratio.The ratio of sugar to acid is the lowest.‘PL-75’ fruit had the highest Vc content,up to 358.81 mg/100 g,‘Qiuping’ was slightly lower,and the lowest content was ‘Dincum’.(4)The effects of different planting time on the cultivation of raspberry ‘Qiuping’ in greenhouse were tested.The three planting time had a certain influence on the fruiting stage of ‘Qiuping’ : the planting fruiting stage was 62 d(May 16),71d(June 1)and 70d(June 16),respectively,and the harvesting period of the planting on June 16 lasted until the late December.Raspberries in the early period of the growth and development,stem diameter and leaf area of different planting time significant difference,but on June 16,engraftment do best,yield and the highest yield,average fruit weight,the largest fruit shape index,total soluble solids is the highest(11.1%)and soluble sugar content,titratable acid content is the lowest(1.59%),sugar acid ratio,the largest fruit of Vc content in the highest(293.91 mg / 100 g).The maximum single fruit weight of ‘Qiuping’ planted on June 1 was 7.2 g.Therefore,in the production of raspberry in northern China,the planting time of seedlings cultivated in greenhouse is suggested to be in the middle of June,which can extend the fruiting period to the end of December,and the fruit quality and yield are also the highest.(5)The effect of different planting distance on raspberry greenhouse cultivation was tested.‘Qiuping’ and ‘Dincum’ both grew better than 20 cm plant spacing when planting with 30 cm plant spacing,while ‘PL-75’ showed no significant difference in growth among different plant spacing,but it was higher than the other two cultivars.The average yield per plant of the three cultivars was higher than that of the other two cultivars when the planting spacing was 30 cm,and the average yield per plant of ‘PL-75’ was higher than that of the other two cultivars.However,for the average yield of the three cultivars,the yield with plant spacing of 20 cm was significantly higher than that with plant spacing of 30 cm,and the average yield of ‘PL-75’ was the highest,as high as 877.5 g.The average single fruit weight of the three cultivars was larger than that of the plant spacing of 20 cm when the plant spacing was 30 cm.The maximum single fruit weight and fruit type index of ‘Qiuping’ and ‘PL-75’ at plant spacing of 30 cm were larger than that of 20 cm,and the maximum fruit shape index of ‘PL-75’ at 30 cm was 1.The soluble solid content and soluble sugar content of ‘Dicum’ and ‘PL-75’ were higher when the plant spacing was 30 cm than 20 cm.The titratable acid content and Vc content of the three cultivars were all higher than that of the plant spacing of 20 cm when the plant spacing was 30 cm,and the sugar acid ratio was the opposite.Therefore,planting spacing is an important factor affecting the yield and quality of raspberries.In order to improve the yield per unit area,planting spacing of 20 cm is recommended.