Triticale (×Triticosecale Wittmack) is the intergeneric hybrid between the female parent wheat (Triticum ssp.) and the male parent rye (Secale ssp.). The early work identifying and then producing primary and secondary triticales is described. Early wheat–rye hybrids were characterized by reproductive disorders and the cytology and meiotic characteristics have received much attention. Chromosome constitution has been studied particularly in relation to R-D substitution. Triticale has always been bred as a self-pollinating crop, although outcrossing can occur, and current cultivars are all nearly homozygous and homogeneous lines. Hybrid breeding (using cytoplasmic male sterility) makes the optimum exploitation of heterosis possible and, with the aid of molecular markers, triticale germplasm is presently being investigated to establish genetically diverse heterotic groups.

The first released spring and winter cultivars were generally characterized by good disease resistance, but low grain yield, shrivelled grain, high protein content, excessive height, lodging and preharvest sprouting. Breeding effort has increased yield, reduced shrivelling and improved test weight but at the expense of protein content, which is now comparable to wheat and rye. Plant height and lodging are also now comparable to wheat and rye. Progress in reducing preharvest sprouting by genetic selection is proving difficult and slow. Triticale may be suitable for grain production and for dual purpose usage for forage and grain.

The role of biotechnology in triticale improvement is described. The future of the crop, especially in low-input systems, and as raw material for industrial uses is considered.

The challenge that faces agriculture at the start of the 21st Century is to provide security of food production in a sustainable way. Achieving this task is difficult enough, but against a background of climate change, it becomes a moving target. However, one certainty is that soil factors that limit crop growth must be taken into account as new strategies for crop management are developed. To achieve this, it is necessary to measure the physical and nutritional status of the root environment in the field. Before considering measurement methods, our understanding of how the plant interacts with its soil environment is reviewed, so that it is clear what needs to be measured. Soil strength due to soil drying is identified as an important stress that limits agricultural productivity. The scope to measure soil factors that directly affect plant growth is reviewed. While in situ sensors are better developed, progress in the development of remote sensors of soil properties are also reviewed. A robust approach is needed to interpret soil measurements at the field scale and here geostatistics has much to offer. The present review takes a forward look and explores how our understanding of plant responses to soil conditions, the newly emerging sensing technologies and geostatistical tools can be drawn together to develop robust tools for soil and crop management. This is not intended to be an exhaustive review. Instead, the authors focus on those aspects that they consider to be most important and where the greatest progress is being made.

Demand for milk has waxed and waned over the last 100 years in response to changing perceptions of its health effects. Milk consumption was promoted for health benefits in the first half of the twentieth century, whilst milk fat has increasingly been regarded as something to avoid over the last 30 years. Emerging research is showing that milk fat provides a number of important components, almost uniquely, within a balanced human diet. Understanding of the role of animal diets in controlling milk fat content and milk fatty acid profiles has grown over this period. The multiple correlated changes associated with milk fat depression have led to a number of mechanistic theories which have not been resolved completely. The detailed mechanisms at the molecular level remain to be elucidated. Interestingly, the two research areas of milk fat content and milk fatty acid profiles have merged as it became clear that some of the intermediates of rumen biohydrogenation are involved in regulating milk fat content. The multivariate nature of milk fatty acid profiles means that future studies must make use of multivariate statistical techniques. These approaches will also be of great value in assessing the consequences of fatty acids for human health, where studies of the effects of single nutrients can be misleading. Issues about the sustainability of the marine harvests mean that attention needs to focus on alternative sources to meet the growing demand for n-3 fatty acids, notably from forages. Whilst attention has focused on milk fatty acids for their effects on human health, future work should also address effects on health and reproductive function of cows offered diets designed to alter milk fatty acid profiles.

Dry matter accumulation and its partitioning to different plant components were studied in six common bean populations (two bred cultivars and four landraces) with different yield potentials. The hypothesis that yield was correlated with leaf area or mass and also with leaf area duration was tested. Leaf area and total above-ground dry matter were sampled weekly between 13 and 62 days after planting (DAP). Yield, yield components and seed yield rate were measured at the final harvest. No differences in total above-ground dry matter were observed among populations up to 62 DAP. Bred cultivars had significantly larger leaf areas than the landraces at the last harvest. Landraces initially partitioned more dry matter to reproductive organs but this was not reflected in higher yields. Temporary differences in growth rate and rate of pod formation were observed among the populations. Landraces, with one exception, tended to grow faster at early stages, and they also reached their maximum number of pods per plant earlier than the bred cultivars. Bred cultivars yielded more than all but one of the landraces. In general, yield was positively correlated with the total number of pods per plant, which in turn was well correlated with leaf area and mass. It was concluded that an increase in leaf area duration and a balanced development of reproductive organs v. other plant components are important traits in conferring improvement in yield of common bean.

Genetic diversity in four local Greek cabbage open-pollinated populations was investigated using RAPD (Random Amplified Polymorphic DNA) DNA markers in 18 individual plants from each population. A total of 24 random primers detected 90 polymorphic bands in the four populations studied, with an average of 3·75 bands/primer. The mean between-population differentiation was close to 40%, leaving 60% for within-population diversity. The individual plants were grouped, based on the Jaccard coefficient, by clustering (Unweighted Pair Group Method and Arithmetic Average – UPGMA) and an ordination (Principal Coordinates Analysis – PCO) methods, resulting in 7 and 6 groups, respectively. In general, there was a notable similarity in the grouping of the individuals with these two methods. In addition, Nei's standard genetic distance between populations, as calculated on the basis of within-population gene frequencies, was employed to group the populations by the UPGMA method. Clustering results were in good agreement with previously reported results based on morphological descriptors applied to the same populations. It was concluded that RAPD markers could be exploited as alternative or supplementary tools to already established methods for the evaluation and classification of cabbage genetic resources.

The development of rice blast disease in four slow-blasting (SB) genotypes was compared with that in the fast-blasting (FB) genotype Karuna, under natural field epidemics over a period of 3 years at five levels of nitrogen, in order to determine if the application of high doses of nitrogen influenced the expression of disease progress in the SB types. The treatment effects were compared through estimation of nine parameters viz. (i) lesion number (LN); (ii) area under disease progress curve (AUDPC); (iii) relative area under disease progress curve (RAUDPC); (iv) logistic apparent infection rate (r); (v) Gompertz apparent infection rate (k); (vi) logit line intercept (logit-a); (vii) gompit line intercept (gompit-a); (viii) time required for the disease to reach 0·25 severity in logistic (T25r); and (ix) Gompertz (T25k) models. There was a significant increase in LN, AUDPC, RAUDPC, r and k with increased levels of nitrogen application in all genotypes, but the rate of increase in disease severity was much lower in SB genotypes than the FB one and did not lead to breakdown of resistance in the SB genotypes, since severity level was much below the economic injury level. Among the nine derived parameters for evaluation of resistance LN, AUDPC, RAUDPC, r and k were best. The AUDPC and RAUDPC had lower degrees of error variance compared with the other parameters and hence were considered superior measures for characterization of disease progress curves.

Tea (Camellia sinensis) in Sri Lanka is grown predominantly on sloping highlands. Incorporating trees as hedgerows along contours is aimed at reducing erosion and improving soil fertility through addition of prunings as mulch. However, there could be significant competition for essential growth resources between the hedgerows and tea. The primary objective of this study was to determine the influence of six hedgerow species (Calliandra calothyrsus, Senna [Cassia] spectabilis, Eupatorium inulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) on mature (6-year-old) and young (6-month-old) tea. This study had three on-farm, long-term (from Nov 1998 to Dec 2002) field experiments. Experiment 1 had 12 treatment combinations with the six shrub species and two mulching treatments (i.e. hedgerow prunings added to the tea plot as a mulch, and unmulched) on mature tea plus a sole tea crop as control. The same was repeated on young tea in Experiment 2 to determine whether resource competition on young tea was greater than that on mature tea. Experiment 3 examined the effects of removing tree root competition on tea by cutting a 1-m deep trench between hedgerows and tea.

In all experiments, total tea yields of hedgerow intercrops, cumulated over the 50-month experimental period, were significantly lower (by 3–50%) than sole tea crops, thus indicating significant resource competition except in the case of mulched hedgerow systems involving Eupatorium and mature tea (18% yield increase). Removal of below-ground competition significantly increased tea yields by 11–19%. Addition of hedgerow prunings as a mulch significantly increased yields of both mature and young tea by 13–21%. Tea yields of hedgerow systems with Calliandra, Flemingia and Eupatorium showed greater yield reductions in young tea than in mature tea, but the opposite was shown with other hedgerow species. There was a significant negative linear relationship between tea yield and pruned biomass of hedgerows. Tea yields of all experiments showed significant negative correlations with several hedgerow characters, which are indicators of their competitive ability. These included hedgerow root density, canopy lateral spread, height and cross-section. In a majority of hedgerow systems, the available phosphorus content of topsoil (0–20 cm depth) was up to 51% lower compared to sole crops. It is concluded that incorporation of contour hedgerows in to an existing tea crop could result in significant resource competition with tea and thereby cause tea yield to decrease. However, there is scope for selection of hedgerow species that minimize competition through spatial and temporal complementarity with tea in resource capture.

Surface liming as a means for controlling the soil reaction in established leys was investigated in a series of 4-year field trials. Application of 625, 1250, 2500 or 5000 kg CaO equivalents/ha in spring of the first year caused an immediate rise in pH in the top 0–25 mm of the soil. The rate and range of the response below 25 mm was related to the precipitation at the experimental sites. Lime-induced changes in pH were not dependent on the initial level of soil reaction, whereas the positive response in grass production was greater and more immediate at sites where pH was below 5·3 rather than above. The increases in yields of macro elements were, in most instances, relatively lower than the increases in dry matter (DM) yields. Important exceptions here were the yields of Ca in all cuts and P in the second cuts, and the yields of Mg when dolomite rather than limestone was applied. The concentration of Ca in the herbage was positively affected by liming according to ruminant needs. The same holds for the concentration of Mg when granulated or coarse dolomite was applied. Liming lowered herbage uptake of Mn, Co and Zn, whereas Mo uptake was increased. There appeared to be no consistent relationship between liming and the plant uptake of Fe and Cu. Dependent on the initial conditions, liming might both improve and worsen the trace element status of harvested herbage with respect to the demands of ruminant animals. It is concluded that frequent surface liming at low rates might be an appropriate strategy for adjusting the soil pH in semi-permanent and permanent pastures.

Two flocks of 42 multiparous (M) and 27 primiparous (P) Nilotic ewes (Southern Sudan) were used in an experiment conducted at the Animal Production Research Centre, Khartoum N., Sudan, to study the effect of age and diet on reproductive performance. Each age group (M and P) was subdivided into two diet groups, fed either a sorghum (So) or a molasses (Mo)-based diet. The two diets were approximately isoenergetic (12·2 and 11·4 MJ ME/kg DM for So and Mo diets, respectively) and isonitrogenous (217 g CP/kg). These diets were formulated from sorghum and groundnut cake or molasses and urea as main sources of energy and protein, respectively. Each of the four diet groups of ewes was further divided into 6 subgroups (replicates) of similar body weights housed and fed together for two successive gestation periods. The results showed that the diet treatments had no significant effect on age and weights at first oestrous (210, 238 days and 22, 20 kg) and at first lambing (407, 418 days and 30, 28 kg) of the PSo and PMo groups, respectively. Age of the ewes and the diet treatments had no significant effects (P>0·05) on feed intake, conception weight, litter size, lamb birth weight, gestation period, postpartum anoestrous period, lambing interval, sex ratio of offspring as well as conception, fertility, abortion and lambing proportions. Primiparous ewes (P) had significantly (P<0·05) higher pre-weaning lamb mortality proportion, whereas the sorghum-based diet groups had higher (P<0·05) gestation body gain and lambing weights.

It was concluded that Nilotic ewes, compared with the other African sheep breeds reviewed, reach sexual maturity at an earlier age and are highly prolific due to their short postpartum anoestrous period. The results also highlight the importance of molasses and urea as efficient and good substitutes for sorghum grains and oil cakes, respectively, in the diets of ewes.

Diets for broiler chickens (n=90) were supplemented with chromium (CrCl3, 6H2O), either alone (0·2 mg/kg diet) or in a combination with ascorbic acid (0·2 mg Cr and 50 mg ascorbic acid/kg diet). The objectives of the study were to ascertain if ascorbic acid had any additive effect on the actions of chromium and whether chromium supplementation could alleviate the nutritional stress in the birds imposed by a reduced energy intake. The birds were fed at the recommended (Bureau of Indian Standards 1992) and at a lower plane of energy. Live-weight gain and diet utilization were higher (P<0·01) when the normal energy diet supplemented with chromium was fed. Food intake (35 days) was higher (P<0·001) in the birds fed with the low energy diet. There was an increase (P<0·01) in metabolizability due to the supplementation of chromium. The metabolizability of crude protein and total carbohydrate increased (P<0·05) when chromium and ascorbic acid were supplemented together. Chromium intake was higher (P<0·001) in the supplemented birds, especially in those fed with the low energy diet (P<0·05), though its retention was higher (P<0·05) when the normal energy diet was given. Chromium in combination with ascorbic acid also enhanced (P<0·01) chromium retention. Blood glucose (P<0·001) and plasma cholesterol (P<0·05) were lower in the supplemented birds and blood glucose was reduced further when ascorbic acid was supplemented together with chromium (P<0·01). Plasma protein increased (P<0·05) in the supplemented chickens. However, variation in the dietary energy concentration did not exert any significant effect on these blood parameters. Plasma chromium was higher (P<0·05) in the supplemented birds, though chromium had little effect in this regard with ascorbic acid. Plasma copper increased (P<0·05) when chromium was supplemented alone and increased further (P<0·05) when chromium and ascorbic acid were supplemented together. Deposition of chromium in the breast and thighs increased (P<0·05) due to supplementation. Protein content and total accretion of protein in the carcass were higher (P<0·05) when chromium was supplemented alone and with ascorbic acid. The supplemented birds had less (P<0·01) fat per 100 g of carcass irrespective of the dietary energy concentration. Weight of the hot carcass increased (P<0·05) due to chromium supplementation although dietary energy concentration did not affect this particular parameter. It was concluded that inorganic chromium supplementation (0·2 mg chromium/kg diet) might effectively enhance the growth performance, diet utilization and carcass characteristics in broiler chickens. Addition of ascorbic acid might also be beneficial in this regard. However, dietary energy concentration was more critical and to yield the maximum benefit of Cr supplementation in broiler chickens, an optimum level was essential.