Study On The Cross Breeding Between Carya Cathayensi And Carya Illinoensis And Properties Study Of Hybridze

Hickory (Carya carthayensis) which is an membership of walnut family(Juglandaceae) is an importment dry fruit and woody oil tree with high economic value. With our country enter the WTO, dry fruit,especially Cillinoensis K. Koch. Come from overseas, has been a big challenge to our country's hickory industry. To improve our hickory industry's competition,select and breed of improved species is a key problem. Crossbreeding is conventional and a valid breeding method. The paper investigated the flowering growth, studied stigma receptivity, fruit set after pollination, quality of fruit and the emerging of the seeds when crossbreeding carried out by hickory as female parent with pecan as male parent.The result are:Hickory is a monoecious tree species. Differentiation of female and male flower bud on hickory are desynchrony, the male flower lasts two years and the female flower differentiates on the current year. With the female flower developing, the stigma color undergoes light red, bright red, purplish red in turn when flowering. The developing speed of flowers are not equal and different developing stages of female flowers are exist at the pollinating period. TTC and acetic red dyeing could be used to determine pollen viability inaccurately. Hickory pollen began germinating after pollinated 8 hours and the pollen tube grew normally through in situ germinating experiment. Female flowers pollinated among the time nearly 10 days from light red to light dark purple of the stigma color had fruit setting. The fruit setting rate was highest at 47.77%when female flowers were pollinated in bright red stage, followed by that when the stigma of female flower was in purplish red, light red and light dark purple. Result shows that there was a good cross compatibility between C. cathayensis and C.illinoensis. 4999 fruits were harvested from from all the four hybrid combinations and 3171 F1 seedlings were obtained. Variation on the color and shape of the fruits was observed.The single fruit weight, fruit length, fruit diameter, fruit shape index, shell thickness, shell weight and nut weight of the hybrid seeds are superior to the female parent nature fruits and reached to the significant. The average of fruit weight of♂l♀l and♂2♀1 combination are 3.79±0.75g and 3.85±0.71g respectively compared with the control at 2.81±0.44g. This study offered reference for the hickory breeding and can provide some cues for revealing the reproductive mechanism on Carya.