Two field experiments were conducted in Egypt in 1985 and 1986 to examine the responses of yield and its components and fibre quality in the Egyptian cotton cultivar Giza 75 to the spray application of 0, 10, 20, 40, 60, 80, and 100 mg of 1,1-dimethyl piperidinium chloride (Pix)/litre at 90 days or at 90 and 110 days after sowing. Number of opened bolls/plant, boll weight, seed and lint index, seed cotton yield/plant, seed cotton and lint yield/ha and yield earliness increased, but lint percentage decreased after Pix application. The number of opened bolls/plant increased after one application, but there was no effect from a further application. There were no effects of concentration or number of applications of Pix on any fibre property.

Synovex-H®, a combination of testosterone propionate and oestradiol benzoate, was implanted on three occasions at about 90-day intervals into Hereford × Shorthorn (HS), Brahman (B) and BX(B × HS) heifers to try to increase live weights and hence pregnancy rates at first breeding. Half of both the implanted and nonimplanted heifers of each breed was treated every 3 weeks to control cattle ticks and gastro-intestinal helminths. Treatment to control these parasites increased live weights, the increase depending on the breed. Implanting with Synovex-H also increased growth, the magnitude of the increase depending on both breed and treatment to control parasites. When parasites were present in significant numbers in the environment, the implanted groups had higher tick and helminth burdens and, in consequence, their live weight gains in response to the implant were lower than those of the nonimplanted group. The reason for the increase in susceptibility to parasites of the implanted group was not sought. It is suggested that it is associated with the presence, either alone or in combination, of the androgen and oestrogen components of Synovex-H.

By the start of the 10-week breeding season, 290 days after the last dose of Synovex-H was implanted, previous advantages of the implanted groups in live weight had been eroded to the point where the differences between groups were no longer statistically significant. Subsequent fertility both as maidens and as first-calf heifers was generally significantly lower in the previously implanted groups of all breeds. Calves born to implanted heifers were not as heavy as those born to nonimplanted heifers both at weaning and 120 days after weaning. The particular regimen of use of Synovex-H followed in this study cannot be recommended if heifers are to be used for breeding.

Determinate forms of field bean (Vicia faba L.), because of their altered growth habit, may differ in phenology from indeterminate cultivars and so their responses to environmental conditions may necessitate different optimum sowing dates. This was studied in autumn-sown field beans at the University of Nottingham at Sutton Bonington by standard growth analysis techniques, final yield components and monitoring of crop growth stages in an indeterminate cultivar, Bourdon, and two determinate populations, 858 and 796 (provided by Plant Breeding International, Cambridge), in three consecutive seasons beginning in 1985/86.

Bourdon yielded significantly more (2·4 t/ha, on average) than the determinate selections as a result of more pod-bearing nodes per stem and seeds per pod and a greater individual seed weight. There was, however, no correlation between seed yield and canopy size, either in total or during pod filling. Determinacy, contrary to expectation, did not increase harvest index. In fact, the reproductive stems of Bourdon had higher harvest indices than those of 858. The yield disadvantage of determinates was therefore exacerbated by the existence of reproductive stems, which, by prolonging the maturation phase, may also detract from a further potential benefit of the determinate habit, namely an increase in yield stability.

There seemed to be no cultivar differences in the temperature requirement for the initiation of developmental processes. An average accumulation of 1239 °C days was required from sowing to flowering. Differences between this and other work in the calculated base temperature for flowering were cautiously explained by the lack of data distinguishing day and night temperature in this experiment and by the use of autumn-sown rather than spring-sown cultivars. It is also suggested that photoperiod may be important in initiating flowering.

Both determinate and indeterminate forms gave the greatest seed yields from the earliest sowing dates.

An induced mutant of rice, designated M41, resistant to several races of bacterial leaf blight, obtained after irradiation with thermal neutrons, was crossed with the original variety, Harebare. Test crosses revealed that the resistance of M41 to the Japanese races I, II, III and IV is controlled by a single recessive gene, considered to be different from four previously identified dominant resistance genes of japonica-type varieties and from three recessive genes in indica-type varieties for resistance to Philippine races. The gene in M41 was tentatively designated xa-nm(t).

Digestibility of neutral detergent fibre (NDF) and monosaccharide components of diets containing 60% untreated straw (UTS) or straw treated with sulphur dioxide (TS) and poultrylitter (1:1) plus 40% concentrate at 700 g/day intake was examined in sheep equipped with rumen and duodenal cannulas. An all-concentrate diet (CD) served as a reference ration. The SO2 treatment of straw increased the apparent digestibility of the NDF, glucose, xylose, arabinose and galactose components of the diet from 58·9, 86·7, 55·7, 82·5 and 91·8%, respectively, in the UTS diet to 73·8, 92·6, 77·8, 88·9 and 94·6%, respectively, in the TS diet. Whereas digestion of NDF and glucose in sheep on the TS diet was slightly lower than in those on the CD diet, digestion of xylose, arabinose and galactose was higher. Thus, the digestibility of total monosaccharides in th TS diet was 90·2 % and that of the CD diet only 61% units higher. The SO2 treatment also increased the total rumen volatile fatty acid (VFA) concentration and the proportion of butyric acid in the total VFA compared with the UTS diet.

Rumen ammonia concentration was 7 mg/100 ml lower and nonammonia nitrogen (NAN) flowto the duodenum was 1·3 g/day higher in sheep fed the TS diet compared with the CD diet. The quantity of duodenal N absorbed in the intestine was 10·7 g/day in the TS diet, close to the value of 11·6 g/day found with the CD diet.

The similarity between the TS and CD diets in total monosaccharides digestion and duodenal Nabsorption, confirms the findings of earlier studies that a TS diet is a highly productive ration.

Complementary interaction between the SO2-treated straw and poultry litter components of the TS diet is discussed.

In a field experiment at Lucknow in 1985/87 and 1986/88, the ‘new’ N carriers urea super granules (USG), neem-cake-coated urea (NCU) and dicyandiamide-treated urea (DCD) and the traditional source of N, prilled urea (PU), were used to supply 150 kgN/ha to the plant crop (first crop after planting) of the cultivar Col 148. The ratoon crop was fertilized at 0 and 150 kgN/ha with PU over all the plant crop treatments. In both plant and ratoon crops, N application increased cane yields but decreased quality: differences in yield resulting from use of the new carriers were not significant, though the fertilizers tended to increase the final plant population density. Uptake and recovery of N were significantly greater using USG, NCU and DCD than using PU. The direct effect of N was 184 kg cane/kg of N applied to the ratoon crop but residual and cumulative effects of N applied to the plant crop on yield and quality of the ratoon crop were small. Adequate direct application of N is therefore suggested for increasing the yields of ratoon cane.