The Selection of Tropical Ley Grasses in Kenya: General Considerations and Methods

Abstract

The cultivation of grasses in Kenya is increasing very rapidly as a result of general improvements in farming methods, and there is now a large and increasing demand for good quality strains of ley grasses suitable for various local conditions. For areas of high altitude, with climatic conditions approaching those of temperate European countries, European or American grasses such as cocksfoot, ryegrass, fescue. brome grass and other less important species can satisfy the demand. The selection of strains of these grasses is dealt with at the high-altitude Grassland Research Station at Mob. The selection and strain-building of tropical grasses, suitable for lower altitudes and warmer, and often also drier conditions, is concentrated on the Grassland Research Station at Kitale, which is situated in Western Kenya at 6,200 ft.(1,900 m.) altitude. The rainfall is about 45 in.(1,100 mm.) per annum, falling mostly in one long rainy season lasting from April to September. It is this latter work which is described in this paper. The conditions of the work of a grass breeder in Kenya differ considerably from those of his counterpart in most of the European continental countries and in the United Kingdom. In Britain and in almost any single country of Western Europe, climatic conditions vary much less than in Kenya, where distinct climates change over relatively short distances from the purely tropical in the coastal belt to the cool and temperate in the highlands. The rainfall varies from about 100 in. per annum on the Nyambeni Range north-east of Mt. Kenya to less than 10 in. per annum in the dry deserts of northern Kenya. Even if the areas of desert and semidesert are excluded, the variation of climatic conditions in the areas of arable cultivation still remains very high, and a large number of species and strains of cultivated grasses is required to suit these various conditions. These requirements cannot be fully satisfied for a long time to come because the extent of the work done on grass breeding in Kenya is only a fraction of that undertaken in the United Kingdom. Although we may hope for better facilities for grass breeding in Kenya and in other East African territories in the future, it is doubtful if the present agricultural economy of Kenya can afford to finance a grass-breeding programme extensive enough to approach the intensity of similar work in Europe, and satisfy the need for high quality grass strains suitable for various regions of Kenya. The grass breeder in this country cannot afford to use the elaborate methods in current use in Europe, and he must concentrate on the simplest forms of selection and strain-building, though he may apply a more elaborate breeding programme in exceptional cases. His main aim should be the simple selection of grass strains of reasonable quality in as short a time as possible. In any country that is young from the point of view of grass cultivation the first efforts of methodical search for better material nearly always produce quick results, and we in East Africa are fortunate in having a very rich grass flora (Bogdan, 1958a), and a particularly wide range of intraspecific variation in the local grass species suitable for introduction into cultivation. We are also fortunate in having amongst the local and introduced tropical perennial ley grasses about 50 per cent, if not more, of autogamous, usually apomictic species, which breed true to type and do not mix, so that the varieties of these can be used direct as ready-made strains.