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present digging into a flat more or less compacted soil surface, The problem of harvesting from the ridge would be similar in many ways to that involved in the mechanical harvesting of potatoes with a broad flat share, as in the Oliver digger. It is hoped that equipment for the experimental investigation of these suggestions will be available in the coming season. It may prove necessary to follow the harvesting operation closely by ploughing in order to prevent com- paction, but there is also the possibility that harvesting from the ridge will of itself help to eliminate compaction, since compaction seems to be in part a con- sequence of the drying-out of the soil on the flat. These suggestions are naturally tentative at the present stage.
Groundnut varieties
With the co-operation of the Tanganyika Territory Department of Agri- culture, the Empire Cotton Growing Corporation (Nyasaland), Mr. J. Sellschop (Potchefstroom College of Agriculture, Transvaal, South Africa), and numerous other departments and individuals in all parts of the world, a considerable number of varieties of groundnuts were represented in the variety collection at Kongwa in the 1947-48 season.
The principal variety trial tested 21 varieties or strains of varieties, some being planted both with and without hand-picking of the seed. The varieties included Spanish Bunch, four types of Valencia, two types of Natal Common, Virginia Bunch, Kidang (from Java), and three types of Manyema, from among the more upright types, and eight runner and semi-runner types from various parts of Tanganyika. Planting (in 28 in. rows at 54 in. spacing) and all operations up to and including the digging of the bunch varieties, were conducted with standard machinery.
Apart from the Valencia type, which was unerringly picked out and damaged by wild pigs from among the randomised plots, all varieties yielded well, Of the upright types, which averaged 1,150 lbs. kernels per acre, Spanish gave 957 lbs. kernels per acre for partly shelled unpicked seed, but proper shelling and picking raised this figure to 1,138 lbs., partly by increasing plant population. Natal Common figures ranged from 1,000 to 1,300 lbs. per acre. Virginia Bunch gave 1,268 lbs., and Kidang just under 1,000 lbs. The Manyema types averaged 1,200 lbs. Runner and semi-runner types yielded from over 1,100 to 1,500 lbs. per acre, with an average value of over 1,250 lbs. kernels per acre.
Twenty other varieties were planted in multiplication rows.
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The experiments confirm the broad suitability in the Kongwa Region of the present main varieties, particularly Natal Common. They indicate, however, that some of the other introductions, particularly Manyema Bunch, have promise. In general, the conditions of the main experiment were favourable both in respect of weather and of soil conditions, the nuts having been very carefully picked off by hand. There is no reason, however, to expect that similar levels of yield could not be obtained generally in practice, under good conditions, although under more adverse conditions greater differences between varieties might have emerged. Some of the Tanganyika varieties of Valencia showed considerable vegetative vigour, which marked also the varieties Japanese and Kidang. There is evidently a wide field for selection and breeding studies in the groundnut crop, particularly for the development of varieties well suited to the more humid longer season conditions of the Southern and Western Provinces.
Oil content of groundnut varieties
Analyses of samples of kernels from the main groundnut variety trial show that, in general, the oil content varies with the degree of uprightness of the variety, being highest in the more upright (bunch) varieties, and lowest in the true runner types. The following table shows the main results of this trial in respect of yield of kernels per acre (summarised above), oil content, and yield of oil per acre. The oil content values can be strictly compared, since they have been obtained frge of statistically designed experimer conducted funder re- latively uniform conditions, and not merely by the analyses of samples of different varieties grown in production areas or under other uncontrolled conditions.
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