Compatibility Of Olive Cultivars In Liangshan

Olive(Olea europaea L.),known as woody oil and fruit species,is originated in the Mediterranean coast,and it has been now spread to the suitable areas of every continent except Antarctica or Arctic outside.Large amount of olive were introduced to China in 1960 s,and breeding,cultivation and management research has been carried out since then.However,the economic production determines the survival and development of the olive industry.There have been researches showed that the majority of olive cultivars were self-incompatible or partially self-incompatible,and cross-pollination could improve their fruit set.Thus suitable pollinizer for the olive cultivars can improve the production and economic benefits.Therefore,this study was conducted in the olive orchard of Liangshan Yi Autonomous Prefecture in Sichuan Province.Ten cultivars(’Picual’,’Arbequina’,’Ottibratica’,’Barnea’,’Koroneiki’,’Crotina’,’Picholine’,’Yuntai’,’Jiufeng-4’ and ’E-zhi8’)were delected as experimental materials.The investigation of meteorological factors,flowering characteristicsand phenotypic characters,combined with the paternity analysis and fruit set analysis were conducted to assess the compatibility of olive cultivars and determine the appropriate pollinating cultivars.This study can not only provide the basis for pollinizer selection to improves the yield and quality of the local olive cultivars,but also provide the basis of the parent selection for the olive crossing breeding programs in the future.In this paper,the conclusions are as those as follows:(1)The meteorological factors all year in the olive garden are suitable for the growth and development of the olive cultivars,guarantying the olive cultivars from cool and heat damage;the temperature(6.1℃-34.3℃),relative humidity(9.0%-85%),precipitation(0-8.9mm)and wind speed(4.1 m·s-1-15.5m·s-1)were also appropriate to the olive cultivars,promoting the pollination,pollen germination,pollen tube development and fertilization.(2)There are some differences of seed germination rate and seedling rate among olive cultivars.The beginning time of seed germination does not affect the level of olive seedling rate,’Arbequina’(54.70%)was the latest,but its germination rate was higher than ’E-zhi8’(52.63%)and ’Crotina’(20.14%),while ’Crotina’ germinated early,but its germination rate was the lowest.(3)The flowering period of the olive cultivars in the olive orchard were from the late March to the early April,lasting 31 days.The longest flowering cultivars were ’Ascolano Tenera’,’Chenggu32’ and ’Picholine’(21d),while the shortest were ’Kaliniot Changye’ and ’Zhanglin’(11d).The flowering period of the 10 cultivars selected in this paper is consistent with most of the cultivars in this orchard,which is conducive to fully open-pollination.The perfect flower ratio and pollen viability varied among olive cultivars,.(4)There were abundant variation among phenotypic quantitative characters and the phenotypic qualitative characters of 10 olivecultivars.There were correlation between14 phenotypic quantitative characters,such as flower number with inflorescence length(r=0.669),stone shape index with fruit shape index(r=0.709),leaf shape index with leaf width(r=-0.414),etc.Among 18 qualitative characters,fruit shape variation was larger(H′=1.089),while the fruit symmetry,the fruit nipple shape and the stone symmetry were smaller(H′=0.325).In the cluster analysisof phenotypic quantitative characters,’Crotina’ was far away from the other 9 cultivars,while in the cluster analysisof phenotypic qualitative characters,’Yuntai’ was the farest.(5)With 12 high polymorphism SSR markers for clustering analysis,36 olive cultivars were divided into 3 groups,and ’Crotina’ with ’Kaliniot Jianye’,’Kalamata’ with ’Picholine’,’Zhongshan-24’ with ’Ascolano Tenera’ were near with each other.Among the 36 cultivars,11 olive cultivars were identified,including 7 true cultivars while the other four cultivars were different with those in the olive germplasm bank.(6)The results of paternity analysis using microsatelite with 636 olive free-pollinated offsprings of 10 olive cultivars showed that,482 offsprings were identified at 80% confidence level,accounting for 75.79% of the total number of offsprings;28 olive cultivars were detected in the 36 candidate male parent cultivars,and the reproductive contribution rate range from 0.21% to 15.77% at an average of 3.57%,the number of mating cultivars were from 1 to 6;the number of pollinated cultivars of the 10 female parent cultivars were from 4 to 11.The effective pollination distance in this olive garden could reach 70 m.When the pollination distance were 10 m,30m,35 m and 40 m,the average reproductive contribution rate were much higher,and when the distances were greater than 50 m,the average reproductive contribution rate decreased gradually.(7)The compatibility of olive cultivars varied between different research methods.In the cross-compatibility research,the fruit-set rate results showed that,’Frantoio’ was more compatible with ’Koroneiki’ than ’Arbequina’,and ’Koroneiki’ was more compatible with’Arbequina’ than ’Frantoio’,while the paternity analysis showed that: ’Chenggu32’ and ’Berat’ were compatible with ’Arbequina’,and ’Kaliniot Jianye’,’Chenggu32’,’E-zhi8’.’Berat’ and ’Coratina’were compatible with’Koroneiki’.In the self-compatibility research,the fruit-set rate research and paternity analysis both showed that,’Arbequina’ and ’Koroneiki’ were self-incompatible.Meanwhile,paternity analysis showed that the 10 selected olive varieties were all self-incompatible.(8)The cross-compatibility were different among olive cultivars.The reciprocal cross-compatible combinations were : ’E-zhi8’3’Barnea’,’E-zhi8’3’Koroneiki’,’Koroneiki’3’Coratina’ and ’Koroneiki’3’Picual’,and the two cultivars in each of the combination could be pollinizers.Cross-compatible combinations could provide the basis for the design in establishing a new orchard,for example: ’Chenggu32’ and ’Berat’ were good pollinizers for ’Arbequina’ while ’Ezhi-8’ and ’Picual’ were passable pollinizers.The cultivars which were compatible with several cultivars could reduce the number of pollinizers and increase the fruit set,for example: ’Koroneiki’ and ’Frantoio’ could be good pollinizers for ’Jiufeng-4’,’Ezhi-8’ and ’Coratina’.