Variations of β-carotene content in sweetpotato [Ipomoea batatas (L.) Lam] storage roots after reciprocal grafts among 5 varieties with different flesh color.

25 combinations were conducted through being reciprocal grafted among five sweetpotato varieties with different root flesh color.Five varieties were 'Yusu 162' with light orange root flesh,'2-19-99' with dark orange root flesh,'Yuzi 263' with light purple root flesh,'2-I19-43' with dark purple root flesh and 'Xushu 18' with white root flesh,respectively.20 traits including the β-carotene content in 25 reciprocal grafting combinations at 65,95 and 125 days after being grafted and the correlationships between the β-carotene content and other major traits were analyzed.Results showsed:(i) Variations of the β-carotene content after being reciprocal grafted were affacted by stocks,scions,developing stages of combination and theirs interactions together.(ii)Variations of the β-carotene content during growing processes were distinct because of the genotypic differences of the stocks and scions.Not only the influences of different scion on the β-carotene contents of the same stock but also the influences of the same scion on the β-carotene contents of different stocks were not same size.There had significant(typeⅠ) and insignificant(typeⅡ) variations of the β-carotene content during growing processes.(iii)Variations of the β-carotene contents in typeⅠ had rarely significant correlation with others traits,but those in typeⅡ had significantly positive correlations with the rations of photosynthate to foliage,to stems and to petioles,and the protein content in fresh roots,and had significantly negative correlations with the length of the longest vine,yield of fresh roots,dry matter content in fresh roots,dry matter yield of roots,ratios of photosynthate to roots,and starch content in fresh roots.(iv)These variations of β-carotene content had different correlationships with the major traits during growing and among different grafting combinations.