Effects of xenia on fruit setting and quality in‘Tunisia' pomegranate

Abstract: 【Objective】Pomegranate(Punica granatum L.),belongs to deciduous shrubs. The flower typesof the pomegranate are divided into two categories: bisexual and male function bisexual. Previous studiesproved that the self pollination setting rate in pomegranate was extremely low,so the pomegranate can betreated as cross-pollination fruit tree. In pomegranate,the method of artificial pollination can be adoptedto provide the basis for rational allocation of pollination tree,improving fruit quality and breeding new va-rieties.‘Tunisia'is characterized as seed deterioration,edible quality and larger arils. According to in-complete statistics,among more than 200 varieties of pomegranate,there are only about 10 soft seed cul-tivars,so we make use of artificial pollination,xenia and other means,get new cultivars with high yield,high quality,soft seed characters.【Methods】‘Tunisia'‘Zhongnonghong'‘Dongyan'‘Yudazi'‘Sanbai'‘Shandazi'and‘Heizitian'were used as male parents and‘Tunisia'soft-seed pomegranate was used asfemale parent. Pollen viability was observed by solid culture medium culture method. Artificial pollinationwas done when the pollen viability reached the standard of pollination. The fruit setting rate was investigat-ed at 40,80,120 d after flowering. The hybrid fruits were harvested at 120 days after flowering,and thefruit quality were detected. Digital vernier caliper was used to measure the fruit longitudinal diameter andtransverse diameter of arils;The electronic analytic balance determined the fruit and seed weight,TA-XT texture analyzer determined the seed hardness,and UV spectrophotometric measured the lignin con-tent of the seed. All data were repeated three times.【Results】The results showed that,except‘Dong-yan',other pollinators can improved‘Tunisia'fruit setting percentage at different levels. At 120 d afterflowering(DAF),the fruit setting rate of‘Tunisia'בYudazi'was the highest(21.4%) followed by‘Tunisia'בSanbai',‘Tunisia'בZhongnonghong'with the fruit setting rate 20.4%,20.3%,respectively,while the fruit setting rate of‘Tunisia'בDongyan'was the lowest(2.7%). The fruit shape index of‘Tuni-sia'בDongyan'was the lowest(0.68);the index of other varieties were ranged from 0.88 to 0.92. The sin-gle fruit weight of all treatments was between 250 g to 600 g.‘Tunisia'בHeizitian'had the biggest aver-age single fruit weight(385 g) which was 106.6 g larger than‘Tunisia'self pollination;‘Tunisia'בShandazi'was 104 g larger than‘Tunisia'self pollination,while‘Tunisia'בDongyan'had the small-est single fruit weight which was 20.5 g lighter than self pollination. The number of seed in the fruit was300-600.‘Tunisia'בHeizitian'was the most which was 182 more than‘Tunisia'self pollination;‘Tu-nisia'בShandazi'ranked the second,which had 506 seeds in the fruit. The number of seeds in‘Tuni-sia'בYudazi'and‘Tunisia'בSanbai'was close to each other and the number of seeds in the fruit of‘Tunisia'בYudazi'was the smallest(349). The weight of 1 000 arils in‘Tunisia'בShandazi'was thelargest,which was 539.3 g. The oeder of other cross combination was‘Tunisia'בSanbai'‘Tunisia'בDongyan'and ‘Tunisia'בYudazi' and the smallest was‘Tunisia'self pollination. The resultsshowed that although the arils of all the cross combinations were sweet,the soluble solids contents weredifferent. The highest of soluble solids content was‘Tunisia'בHeizitian'which was 15.7%,and thelowest was‘Tunisia'self pollination which was 14.5%. Among the combinations,‘Tunisia'בShandazi'had the largest edible rate which was 72.19% and followed by‘Tunisia'בSanbai'and‘Tunisia'בHeiz-itian'.‘Tunisia'בDongyan'had the lowest. Arils juice yield of‘Tunisia'בDongyan'was the larg-est,and followed by‘Tunisia'בShandazi'and‘Tunisia'בSanbai'. The arils juice yield of‘Tunisia'בZhongnonghong'was close to that of‘Tunisia'בYudazi'. The results of the seed hardness determina-tion showed that: all combinations produced soft seeds. Among them,the hardness of the‘Tunisia'selfpollination combination was the smallest(1.51 kg);the seed hardness of‘Tunisia'בHeizitian'was 1.67kg;the hardest seed hardness was‘Tunisia'בShandazi',which was 2.22 kg. The lignin content in seedwhich related with the seed hardness,was ranged from 17% to 27%.‘Tunisia'בShandazi'had the high-est lignin content which was 26.18%;the lignin contents in‘Tunisia'בDongyan',‘Tunisia'בSan-bai'and‘Tunisia'בZhongnonghong'were 23.77%,21.64% and 21.27%,respectively;the least lignincontent was observed in‘Tunisia'self pollination combination.【Conclusion】Taking‘Tunisia'as themother parent,all the hybrid combinations produced soft seeds.‘Tunisia'בYudazi'and‘Tunisia'בSanbai'had the higher fruit setting rate.‘Tunisia'בHeizitian'and‘Tunisia'בShandazi'had thebetter fruit quality.‘Tunisia'בYudazi'and‘Tunisia'בHeizitian'had the smaller seed hardness,meanwhile they had the lower lignin content. Overall,compared with the‘Tunisia'self pollination,otherpollinators can improve‘Tunisia'fruit setting percentage and fruit quality at different level. The hard-ness of seed was positively correlated with lignin content. The appropriate varieties for pollination areneeded to be selected carefully.