| Dichondra repens Forst is a warm season ground-covered lawn plant belongs t o genus Dichondra family Convolvulaceae.Due to its low grass layer,long green period,attractive shape,stronger adaptability,Dichondra repens is widely being use d to construct ornamental lawns and modeling of garden landscape.In the present study we used two grass varieties one is from America named as ’Common’ and ot her is ’Duliujiang’ native to China as control and compared with ’Xiaoshao’ a new Strain of Dichondra repens selected as a national grass variety regional test in 2017,now carrying out a productive test of the new strain ’Xiaoshao’ in Qingbaijiang,Ya’an and Chongzhou,to investigate its phenotypic and molecular genetic charactrst ics of the new strain ’Xiaoshao’ materials and ’Common’,’Duliujiang’,’Jinning’,’Dus han’,’Lantian’ materials.The majority of results were as follows:(1)In this case,we planted turf blocks 10×10cm at the distance of 30 cm each at three different locations in Sichuan i.e Qingbaijiang,Ya’an,and Chongzhou.All the blocks were allowed to grow and formation speed was recorded between 80 days to 129 days.In Qingbaijiang the formation speed of ’Xiaoshao’ was 82 days which was 2 days earlier than’Common’ and 2 days later than ’Duliujiang’ however,in Ya’an the formation speed of’Xiaoshao’ was faster than ’Common’ and ’Duliujiang’ about 20 and 2 days respectively.Moreover,the formation speed of ’Xiaoshao’ in Chongzhou was 21 days and 7 days faster than ’Common’ and ’Duliujiang’.(2)Field-observation results from past two years showed that the height of ’Xiaoshao’lied between ’Common’ and ’Duliujiang’,and ’Xiaoshao’ had higher plant density,longer green period,more green colour of leaf and uniformity,no or less pest attacks and diseases.At each experiment region,green period of ’Xiaoshao’ was up to 320 d,which was 0-12 d longer than Common’ and 2-14 d longer than ’Duliujiang’.In addition,the comprehensive evaluation score of lawn values for ’Xiaoshao’ ranged from 7.4 to 7.9,’Common’ from 6.8to 7.3,and ’Duliujiang’ from 7.0 to 7.4.(3)As compared to ’Common’ and the rest of domestic Dichondra repens Strains,’Xiaoshao’ exhibited marked difference in color,plant density,leaf area and inflorescence.’Xiaoshao’,’Jinning’ and ’Dushan’ shared the same dark green colour,’Common’ was the darkest green,and ’Duliujiang’ and ’Lantian’ were light green in colour.’Xiaoshao’,’Jining’and ’Dushan’ had medium size leaf,’Duliujiang’ and ’Lantian’ had smaller,and ’Common’had larger-leaf size.The order of plant density was ’Lantian’> ’Duliujiang’>’Xiaoshao’>’Dushan’>’Jinning’>’Common’.The order of the inflorescence diameter was ’Jinning’>’Common’>’Duliujiang’>’Lantian’>’Xiaoshao’>’Dushan’;the petal length of ’Xiaoshao’was shorter than both of ’Common’ and ’Duliujiang’ and longer than ’Jinning’,’Dushan’ and’Lantian’,and the calyx length of ’Xiaoshao’was longer than that of ’Common’ and shorter than ’Jinning’,’Dushan’ and ’Lantian’;The calyx of ’Xiaoshao’ was yellow-green,and all others had green or dark green except ’Dushan’ in which calyx was not found’.(4)The initial flowering period of the tested Dichondra repens varied from late February to mid March,the full flowering period from early March to mid March,the fruit ripening period from early June to mid June,and the breeding period lasted about 90 days.In addition,’Common’ fruited in large and ’Lantian’ fruited in a small amount,and ’Jinning’,’Dushan’,’Xiaoshao’ and ’Duliujiang’ were all not fruitful.(5)Using 18 pairs of SSR primers in sweet potato to amplify DNA through PCR for 6of Dichondra repens,a total of 232 bands were amplified,an average of 12.89 bands per pair of primers,of which 203 bands were polymorphic,and the polymorphism ratio was87.50%.The genetic similarity coefficients of all six Dichondra repens were 0.580-0.835,in which the genetic similarity coefficient of ’Xiaoshao’ and ’Duliujiang’ was the largest,and smallest for ’Common’ and ’Lantian’,and the polymorphic band amplified by the primer IBM13 was completely different in all six Dichondra repens,which could distinguish the new Strain from rest of varieties at the molecular level. |
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