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To evaluate the domestication and cultivation value of wild Actinidia eriantha germplasm resources in the mountainous areas of southern China, 145 genotypes collected in the Magu Mountain Nature Re...

The chilling requirements of 35 kiwifruit genotypes in south China were evaluated. The number of hours at low temperature (0–7.2°C) required to break natural dormancy was determined. Results showed that the average chilling requirement of the 35 genotypes was 675 h. The chilling requirement of 89% of the genotypes ranged from 576 to 768 h. Overall, the chilling requirements of genotypes of Actinidia chinensis var. deliciosa were higher than those of Actinidia eriantha, which in turn were higher than those of A. chinensis var. chinensis. These results provide a basis for breeding and selection of kiwifruit cultivars suitable for cultivation in low-chill areas of south China.

Kiwifruit has a high commercial value and is especially rich in vitamin C. Successful fruit set in kiwifruit depends on several reproductive processes including pollen germination and pollen tube growth. In this study, we investigated impacts of heat stress temperatures (27, 30, 33 and 36 °C) on pollen germination and pollen tube growth of 25 wild genotypes of Actinidia eriantha. Before heat stress application, pollens were stored at −20 °C for 6 months. The results showed great variation among genotypes in each treatment. Eight genotypes showed no significant change in the reduction of germination percentage. Some genotypes gave unsteady response in tube growth. MH22, MH30 and MH58 were evaluated as more tolerant genotypes. In contrast, MH48 and MH67 were the two most sensitive genotypes. The research of heat stress impact on pollen germination and pollen tube growth will be helpful for breeding new varieties and the identified tolerant genotypes can be used in future breeding programmes.

Plantlets were regenerated from leaf explants of Actinidia eriantha Benth. cv White (kiwifruit). The best medium for adventitious shoot formation from leaf blade strips was Murashige-Skoog (MS) medium with 0.1 mg L−1 NAA and 2.0 mg L−1 BA. The frequency of shoot regeneration (%) was dependent on the size and the part of the leaf from which the explant was taken. The highest frequency of shoot regeneration was 7.30±2.61 shoots per explant, for explants taken from within 0–3 cm of the leaf blade base, near a vein and not on the leaf edge. When using petiole-derived explants, a maximum frequency of adventitious shoot regeneration of 79.17% with 6.54±2.31 shoots per explant was obtained using 0.1 mg L−1 NAA and 2.0 mg L−1 ZT in MS medium. The highest rate of rooting obtained was 96.67% when using 1/2 MS medium containing 0.6 mg L−1 IBA and 93.75% when using wet moss without IBA. This is the first report to study the effect of explants taken from different parts of the leaf blade on shoot regeneration...

We report the release of a new, large-fruited kiwifruit cultivar, ‘White’, selected from Actinidia eriantha. Fruit of ‘White’ had a mean fruit weight of 94 g, and a maximum fruit weight of 132 g at harvest in Zhejiang, China. The mean fruit weight is c. 2–4 times that of wild A. eriantha fruit found in Zhejiang and nearly 4 times that of ‘Bidan’, the only other registered A. eriantha cultivar. The fruit are oblong and the peelable skin is covered with dense white hair. The flesh of ripe fruit is green and has good eating quality but little juice. The soluble solids concentration was 14.7%, total sugar 9%, total acid 1.24%, and vitamin C 628.37 mg/100 g fresh weight. Its harvest season is during the last 10 days of October in the south of Zhejiang province, which is c. 2 weeks later than A. deliciosa ‘Bruno’ in the same area. It is sometimes referred to as the “banana kiwifruit” because the skin is easy to peel. This new cultivar has been registered in China (PVR No. CNA20050673.0).

Actinidia eriantha Benth. usually flowers in late spring on shoots that develop from buds initiated during the previous growing season. Documented here is the occurrence of secondary floral shoots in summer on both male and female vines. Those summer shoots were produced by “new” buds initiated during the current growing season. A series of sequential shoot tip removals, to force the most distal developing buds, showed that those secondary floral shoots could be induced when the primary shoots were tipped as early as late November (late spring).