Propagation of kiwi

Propagation

       The propagation through cuttings is most rapid and suitable method of multiplication. Various types of stem cuttings—hard wood, semi-hardwood and soft wood—are quite successful, though the technique and success in rooting varies. The cuttings 0.5–1.0cm thick with relatively short internodes and 15–30cm long are ideal. Hard wood cuttings are prepared during the dormant season (January–February) from the previous year summer growth. Well-matured dormant shoots are used for cuttings having at least 3 healthy bold buds from middle of the shoot. Tips of the shoots should be avoided as they give a very low rate of rooting. The cuttings of the central and basal parts are ideal. Cuttings having more number of spurs should not be selected. The cuttings are treated with IBA (500ppm) for 10 seconds and set deeply in moist rooting medium. To prevent the cuttings from desiccation and rotting the top portion of the cuttings are waxed. A rooting medium consisting of farmyard manure: sand: leaf compost: soil in the ratio of 1:1:1:1 results in highest rooting in open conditions. The cuttings should be planted, 6–8cm apart in rows spaced at 12–15cm. The nursery bed should be thatched or shaded with shade net. Irrigations are given frequently. Adequate drainage should be provided to keep the nursery bed weed-free. As they become about 15.25cm high, their terminal growth is pinched off to divert the food and nutrients for root growth and development.

       Hardwood cuttings can also be raised under intermittent mist in a mist propagation chamber or polythene house. The rooting media consisting of sand, farmyard manure, soil, saw-dust and coal in a 2:1:2:1:1 ratio gives a good success. The cuttings should be treated with a mixture of IBA (2,500ppm) and NAA (2,500ppm) solution for 20–30 seconds and misted for 2–3 minutes at every 15–20 minutes intervals for 5–6hr in a day.

       Soft wood cuttings generally root easier and quicker than hard wood cuttings but they require more attention and sophisticated propagating structure (mist chamber). Semi-hard wood cutting with 3 buds and 0.5–1.0cm in thickness from the middle portion of the current season’s growth are taken in July. A wound of about 1cm length is made on one side of the base just below the node. Lower leaf on the basal bud are removed while 2 leaves are retained but reduced to 20–50% by a circular cut maintaining the natural leaf shape. The cuttings are treated with IBA (4,000–5,000ppm) for 10 seconds and planted in the mist chamber having sand as the rooting media. Intermittent mist should be applied at 10-min. intervals. With this method 70–75% success is achieved.

Stratification

       Freshly extracted kiwi seeds from ripe fruits need 10-week stratification in different layers of sand under field conditions. Under agroclimatic zones where winter temperature is sufficiently low to 15°C, kiwi seeds can be sown directly in the seed beds during the first fortnight of December. Seed beds should be mulched with grass, till the seeds start germination.

Germinating seeds and baby seedlings are very sensitive to sun-scald and direct sun. The young cotyledon leaves turn brown, developing damping off symptoms. They ultimately die. Thus on starting of seed germination, mulch should be removed and the seed bed should immediately be covered with hessian cloth (gunny bag) or with pruning wood thatch till 5–6 leaves appear on the seedlings.

      The grafting should preferably be done during dormant season, January–February being ideal time. The scion of the thickness of rootstock should be selected and packed in sphagnum moss. It can be stored at 4°C in refrigerator if necessary. Of various methods of grafting, whip and tongue are ideal.

Budding

      Seedlings become ready for budding normally at the end of first growing season when the stem diameter is about 6–8mm. Scion buds are obtained from the current season’s growth. One or two buds are inserted on the main stem by T-budding method at 10cm above the ground level. Chip budding during mid-February results in bud take as high as 95%. The bud is firmly secured into position by tagging with a polythene tape. When the bud has taken, the top of the vine is cut above the union during the following dormant season. The protection to the young growing shoot from the bud is very important because it is very brittle and easily breaks.