Study On The Biological Characteristics And Set Two Provincial Standards Of Seedless Honey Pummelo

Seedless honey pummelo was introduced to China from Malaysia in 2002,planted in Chengmai,Danzhou,Tunchang and other places in Hainan province.It grows well and has great market potential,but the systematic research on its biological characteristics and cultivation techniques is little.This research adopted laboratory analytical method and field survey method to observe the phenological periods,root distribution,floral morphologenesis,pollen morphology and fruit quality,etc of Seedless honey pummelo.According to national standard GB/T1.1-2009 and Hainan local standard DB46/T 74-2007,two local standards "Technical regulation for production of Seedless honey pummelo" and "Seedless honey pummelo" are established.It intends to provide a basis for high quality cultivation techniques of Seedless honey pummelo as well as promote pummelo industry's sustainable development in Hainan Province.It has important practical significance.The results are as follows:(1)According to the observation in 2015,the phenological period of Seedless honey pummelo can be divided into:infancy(early January),bud(late January),early flowering stage(early February),blooming stage(late February),wither period(mid-March),the first physiologic fruit drop(early April),the second physiologic fruitdrop(late April),fruit ripening(early August to early September),shoot growth stage(four times a year,respectively in early December,early May,mid-August,and late October).(2)The distribution of root systems of Seedless honey pummelo is observed by the trench method.The root distribution of Seedless honey pummelo is shallow,mainly distributed in the depth of 0?20 cm,0?2 m from the main trunk in the soil.The largest number of roots is between 0?2 mm,a small number is between 2?5 mm and very few is between 5?10 mm.(3)The flower bud morphological differentiation is studied by paraffin method.The differentiation process can be divided into six periods,which are undifferentiation period,initial differentiation period,calyx differentiation period,stamen differentiation period and pistil differentiation period.The flower bud morphological differentiation starts from late December to late January,lasting 20?25 days.(4)The pollen morphology is studied bu no means of the scanning electron microscope.Its overall look is nearly spherical,with four germ furrows.The pollen size is 18.37×25.13 ?m(P×E).The pollen surface looks like a net pattern,in which meshes' sizes are different,with diameters between 0.20?0.60 ?m.(5)The fruit growth curve shows as a single S.It grows fast after flowering 40?70 days,grows slowly after flowering 70?140 days and its size will not grow after 140 days.The fruit growth rate of the transverse diameter is greater than that of the longitudinal diameter.(6)Mature Seedless honey pummelo is oblate.Its transverse diameter is 16.88 cm and longitudinal diameter is 14.70 cm.Its mean fruit weight is 1417g.The Seedless honey pummelo is smooth,seedless and yellow-green.Fruit quality is good with 11.5 cm of Peel thickness 63.7%of edible rate,85%of pulp moisture content,13.3%of TSS,0.46%of acid and 40.5 mg/100g of Vc.Pulp crisp and tender with rich sweet flavor.(7)The experiments use 3 different bagging materials,including white single paper,yellow single paper and white non-woven bag.There are no significant differences among them on the fruit color,vertical and horizontal diameter,peel thickness,edible rate and TSS of Seedless honey pummelo.Non-woven bagging fruit weight is higher than that of white single paper bagging while the white paper bagging fruits' acid and Vc content is higher.But the white non-woven bags are more durable than the white one and yellow one.In conclusion,white non-woven bag is the best choice.(8)Make Technical Regulation for Seedless honey pummelo Production to describe and explain the garden selection,planting methods,fertilizer and water management,fruit management,pests control and harvesting time and methods,etc.(9)Set a fruit grading standard,Seedless honey pummelo to divide fruits into 3 kinds of specifications according to fruits' weights.They Respectively are King(w?1800g),Large(1400g?w<1800g)and Medium(1000g?w<1400g).Meanwhile,according to mature fruit shape,surface,specification and color,three classes are divided,super-class,first-class and second-class.The standard also describes some requirements such as sanitary condition,physicochemical property,packaging,storage,transportation.