Comprehensive Evaluation And Identification Of Genetic Specificity Of Early-maturing Navel Orange Cultivar ’Navelina IC’

As an important part of fruit tree breeding,variety introduction is widely used in fruit tree breeding because of its low cost and short cycle.The main varieties of navel oranges in my country are single,the maturity period is too concentrated,there are few early-maturing navel oranges,and the late-maturing navel oranges are easily threatened by freezing damage,especially in Hunan,which is greatly affected,causing a lot of economic losses.In this study,the early-ripening navel orange cultivar ’Navelina IC’ and control varieties such as Nevlina IS,Nevlina M,Powell,Chislet,Ignace,Jinxiangcheng and Newhall were observed.Biological traits,adaptive evaluation and genetic specific identification of ’Nevilina IC’.In order to quickly screen out the early-maturing characteristic navel orange varieties with good comprehensive performance,improve the structure of domestic navel orange varieties,and provide molecular basis for the identification of navel orange materials in the future.The main results of this study are as follows:1.Evaluation of Biological Characters of Early-ripening Navel Orange Variety’Navelina IC’ and Control Varieties’Navelina IC’ entered the budding stage,the shoot-out stage,the budding stage and the dew-white stage in late February,and entered the early flowering stage,the full blooming stage and the blooming stage on March 26,April 04 and April 9 respectively Xie Huaqi,the first physiological fruit drop on April 24,and the second physiological fruit drop on June 03.The earliest and latest phenological periods above are Chislet and Navelina M,respectively,with a difference of about 11-15 d.The earliest tinting period of ’Navelina IC’ is October15 th,the latest is November 30 th in Chislat,and the shading period of Newhall is October29 th.The spring shoots of ’Navelina IC’ were significantly smaller than Newhall except for leaf length,the summer and spring shoots were significantly longer than Newhall,and the petal length and pistil length in floral organs were significantly longer than Newhall.The average fruit weight of ’Navelina IC’ is about 301.70 g,the transverse diameter is82.61 mm,the longitudinal diameter is 82.69 mm,the fruit shape index is 1,the fruit is nearly round,the skin thickness is 3.81 mm,and the juice yield rate is 48.56 %.The edible rate was 73.45 %,the TA content was 0.60 %,the TSS content was 10.97 %,and the Vc content was 54.62 mg/100 m L.There was no significant difference in other fruit indicators except skin thickness.The results showed that the fruit of ’Navelina IC’ had early maturity,thin peel and good fruit quality.2.Adaptability evaluation of early-ripening navel orange variety ’Navelina IC’In this experiment,the phenological period and fruit quality of ’Navelina IC’ in different cultivation environments were analyzed and evaluated.The results showed that the phenological period of ’Navelina IC’ differed greatly in different cultivation sites.The germination and shoot-out dates of the ’Navelina IC’ cultivated in Yizhang County were on February 10 and February 20,respectively.,were about 26-27 d earlier than the ’Navelina IC’ cultivated in Changsha City;the budding period and the blooming period were March 13 and March 23,respectively,9 d and 5 d earlier;the flowering period was From April 7th to April 20 th,about 9-10 days earlier;the first physiological fruit drop period was 7 days earlier,the second physiological fruit drop period was 3 days later,and the coloring period was 21 days earlier,respectively on May 06 18 June and 21 September.The fruit of’Navelina IC’ cultivated in Changsha City was slightly smaller,but the overall fruit quality was slightly better than that of ’Navelina IC’ cultivated in Yizhang County,and the TA content showed a significant difference.The phenological stages of ’Navelina IC’ under different cultivation conditions are quite different.Except for the second physiological fruit drop period and coloring period,the above phenological stages of ’Navelina IC’(greenhouse)plants are all higher than those of ’Navelina IC’.IC’(open field)was about 17-21 d earlier,the second physiological fruit drop period was 12 d earlier,and the coloring period was delayed 3 d.When ’Navelina IC’ was planted under different conditions,the fruits of’Navelina IC’ under facility cultivation were larger,the TA content was higher,the juice yield and solid acid ratio were lower,and they were all similar to those in the open-air environment.significant difference.The comprehensive results showed that the comprehensive fruit quality of ’Navelina IC’ was excellent in Changsha City,Yizhang County and facility cultivation,and this variety was suitable for cultivation and application in different environments.The disease resistance evaluation results of ’Navelina IC’ and control varieties showed that both ’Navelina IC’ and control varieties were susceptible to citrus Huanglongbing(HLB).The quality of HLB fruit was significantly different from that of normal fruit.Among them,the single fruit juice weight,juice yield,TA content and solid acid ratio of ’Navelina IC’Huanglongbing fruit were significantly decreased,and Vc content was significantly increased;The edible rate and TSS content were significantly different from those of normal fruits;the edible rate,TA content and solid acid ratio of Navelina M were significantly reduced.3.Identification of genetic specificity of early navel orange cultivar ’Navelina IC’Molecular identification of the genetic variability of the early-ripening navel orange’Navelina IC’,seven imported navel orange varieties and one self-selected navel orange variety.Five pairs of specific primers including P68,P179,SSR2,P181 and P184 were selected by screening primers and exploring the annealing temperature.The results showed that ’Navelina IC’ could be distinguished from other cultivars,and all the 9 navel orange cultivars could be distinguished from the rest of the 9 navel orange cultivars by using a single primer or a combination of multiple primers,laying the foundation for future authenticity identification.To sum up,the fruit of ’Navelina IC’ has early maturity,uniform fruit shape,thin skin,good flavor,and is susceptible to citrus HLB.The breeding of this variety will enrich citrus germplasm resources and advance the market time of navel oranges,which provides the guarantee of early-maturing varieties for the annual supply of fresh fruits.