The Effect of Seed Treatments, Nursery Technique and Storage Methods on the Germination of Tung Seed

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Webster C.C
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Tung trees of the species Aleurites montana are deciduous trees which in Nyasaland begin the season's growth at the commencement of the warm weather in September, flower and set fruit from the end of September to early November, and continue growth until the end of the rains in April or May, when the fruit falls and the leaves are shed. An indication of the climatic conditions in the main tung-growing area may be obtained from the figures for temperature and rainfall at the Tung Experimental Station shown in Table 1. The normal time for sowing seed in nurseries is in May and Jpne, early in the cool, dry season. Such fresh seed usually gives a germination of from 7'5 to 90 per cent, but owing to the relatively low temperatures germination is slow and is not complete for at least 3! months, while the growth of the young plants is also retarded by the cool, dry weather, in spite of the fact that the nurseries are watered once or twice daily from the time of sowing to the onset of the rains in November or December. As a result, seedlings have to remain in the nursery for 16 to 18 months before they are ready for budding, for although some of them may be big enough by February or March of the following year, there is no great advantage in budding then because they cannot be planted out as budded stumps until the rains begin in November or December. If the seeds are stored through the cold season, and then planted when the warm weather comes in September or October, germination is more rapid and the young seedlings grow more quickly, but unfortunately loss of viability occurs during storage and the percentage germination obtained is usually only from 30 to 50. If this loss of viability could be prevented it would be advantageous to delay sowing until September-October as the expense of watering over a long period would be saved and, owing to the more rapid germination and growth, the plants would still be ready to bud by October or November of the following year. Alternatively, the period in the nursery could be shortened if means could be found of accelerating germination and growth during the cold season so that the plants were big enough to bud by November or early December of the same year, but this would not eliminate the expense of watering. The preservation of viability during storage is, however, important from another point of view, as some planters find it desirable to plant out basket seedlings at the beginning of the rains for budding in the field in the following year, and to produce such plants of suitable size the seeds must not be sown until August as if they are sown earlier the plants are too big by the time the rains break.
East African Agricultural And Forestry Journal, XIV (No. 1), p. 38-48