SummaryGroundnuts (Arachis hypogaea L.) have been found to be one of the most promising additional cash crops for diversifying Sudan agriculture. Three hundred and thirteen agronomically distinct forms have been separated from 171 varietal samples, and 121 short-maturing upright bunch types and 49 long-maturing spreading bunch types have been tested in a series of trials over several years in four climatic regions. Among upright bunch varieties, PJ121070 and Large Natal 142 appeared to be the best selections as oil and confectionery types respectively, and among spreading bunch varieties, MH.372, Beladi Bunch and NJ37 for oil, confectionery kernels and unshelled nuts respectively. A hybridization programme was started in 1959 to improve the existing varieties of groundnuts and to produce non-germinating upright bunch varieties for growing in the heavy clay soils. Inheritance studies indicated the dominance of an alternate pattern of branching, prostrate plant habit and long maturity. Dominance of testa colours was in the order of purple–red–russet brown–light brown–white. Recessive albino seedlings were observed only in crosses involving different branching pattern. There appeared to be no association between the various characters studied except maturity period, which was related to branching pattern and growth habit.

1. The effect of three factors (nitrogen level, time of nitrogen application and weed control) and their interactions on three different plant densities of winter wheat have been measured. Data concerning the growth, development and yield have been examined.2. Plant populations of 104,000, 155,000 and 281,000 per acre produced on the average of all treatments 21·3, 22·4 and 23·2 cwt. grain per acre, respectively.3. An increase in nitrogen fertilizer to the 2 cwt. sulphate of ammonia per acre level increased the grain yield of all populations. This response followed an increase in the number of tillers and an increase in the percentage of tillers producing ears. There was no significant interaction between nitrogen level and plant density. The nitrogen content of the grain increased with nitrogen level.4. Time of nitrogen application did not affect the grain yield, although it did cause considerable differences in the growth and development of the plants. There was no significant interaction betweentime of application and plant density. The late application of nitrogen produced a lower yield of straw and a higher nitrogen content in the grain.5. Weed control increased the grain yield of all plant populations, this increase following an increase in the number of ears per plant. There was a significant interaction between weed control and plant density. Weed control raised the yield of the low plant population by 3·9 cwt. per acre compared with 0·9 and 2·0 cwt. for the medium and high populations. Weed control also increased the nitrogen content of the grain.6. The only other interaction concerning grain yield which was significant was that of weed control with time of nitrogen application. Weed control increased the yield of the early and late applications but inexplicably reduced the yield of the intermediate date.7. It is concluded (a) that the experiment provided no evidence that the yield of a thin stand of winter wheat can be increased further by altering normal nitrogen fertilizer application or by altering the time of application of the fertilizer; (b) that for good results weed control is essential where the plant population is low.

SummaryAn early upright-bunch variety of groundnut, Barberton, and a medium-late spreading-bunch variety, Ashford, were compared at 7·5, 15·0 and 30·0 cm. intra-row spacings planted at one and two kernels per hill on 60 cm. ridges in the irrigated heavy clay soil of the Sudan Gezira in 1963 and 1964. Barberton was harvested on days 95, 110 and 125, and Ashford on days 125, 140 and 155 after planting in July–August. Ashford outyielded Barberton at the lower densities, and the best pod yields were obtained on day 125 harvest at a population of 55,000–60,000 plants per acre. A higher plant population depressed the yield of Ashford while the increased pod yield of Barberton was not significant. Field germination of kernels increased more in Barberton with delay in harvest and with decrease in plant population than in Ashford. Mean pod and kernel weights and shelling out-turn of Barberton increased with delay in harvest. Barberton gave higher oil content and shelling out-turn, and lower proportion of pods with single kernels than Ashford. The highest population of Barberton gave the best oil content in early harvests. In general, the arrangement of plants within rows at similar populations had only small effects except on the quality of nuts, which was improved by planting single kernels at close spacing (7·5 cm.) with the variety Barberton and two kernels at wide spacing (15·0 cm.) with Ashford, at optimum plant populations.