Seedling tests for reaction of tomato cultivars to leaf mould (Cladosporium fulvum) showed that a single race 1·3, or a mixture of races 1 and 3, was present at four sites in the Western State of Nigeria sampled at different times during 1967 and 1968. Vetomold, Vantage, Vinequeen, Astronaut, Floradel, and Tarran were immune and Purdue 135 was resistant. Genetic tests showed that the Cf2, gene conditioned immunity and that the Cf4 gene provided resistance.

In any experiment the land will not be completely uniform and it is helpful to have ways of allowing for the variation. Some sources, for example altitude, will be obvious; some will be permanent but less obvious, such as depth of topsoil; and some may depend upon season and so be unpredictable. Various methods of local control have been suggested. Where the experimenter has good knowledge of the land it can be divided into blocks, each as far as possible uniform within itself. Then comparisons are made within the blocks rather than within the area as a whole. Where such knowledge does not exist, it is sometimes reasonable to make an assumption about the fertility pattern and make use of that, as in a row-and-column design like a Latin square. There is also the possibility of judging the fertility pattern from the data themselves and assessing the performance of a plot by reference to that of its neighbours.

The approach will be to generate bodies of data on the computer to form realizations of diverse fertility patterns and to use all methods on all realizations, noting success and failure.

When the variation forms a trend, blocks succeed only if they are aligned along fertility contours; the other methods do not depend upon orientation. Row-and-column designs can fail badly if the rows and columns interact. Some random variation is inevitable and it makes all methods less effective, especially nearest-neighbour methods, which can fail also when there are discontinuities. Random patches of different soil types are very difficult to deal with and any method might fail.

The aim of this work was to compare gas exchanges from leaf to whole plant scales, in two Ethiopian accessions (‘E083’ and ‘E027’), and two bred cultivars (Iapar 59 and Catuaí 99) of Arabica coffee (Coffea arabica L.) cultivated under irrigated and rainfed conditions. Variations in gas exchanges were evaluated over four phenophases (leaf expansion – BE1 and BE2, and berry harvesting – BH1 and BH2), covering the first two production years in the coffee life cycle. We addressed the following questions: Are gas exchanges modified by water availability at leaf and/or plant scales? Do bred cultivars and wild accessions differ in their physiological responses to water availability and phenophases? Photosynthesis (A), stomatal conductance (gs), and transpiration (E) were measured on the recently fully expanded leaves at the upper canopy stratum. The functional-structural plant modelling (FSPM) was used to integrate A at whole plant photosynthesis (A”p), based on 3D virtual trees constructed under VPlants modelling platform. Despite high A values of ‘E083’ overall phenophases, a strong decline in A”p under rainfed condition was observed due to lower plant leaf area as compared to irrigated condition. Catuaí 99 and ‘E083’ were more sensitive to drought than Iapar 59 and ‘E027’, considering photosynthesis at leaf and plant scales. At the last BH2 phenophase, A, gs, E, and carboxylation efficiency were similar between irrigated and rainfed conditions for all genotypes, suggesting some acclimation of leaf gas exchange to the environment. However, A”p benefited by water management in all phenophases as plant leaf area increased. These findings revealed the need to develop methodologies for structural and functional analyses at plant scale, an important step towards the realistic responses of plants and orchards to the surrounding environment.

Fruit quality is a key factor – beginning with the producer, continuing through the supply chain, and ending with the consumer. It is described by multiple indicators and varies during the growth and ripening of the fruit. This study focused on two main aspects of Cogshall mango (Mangifera indica L.) quality: (i) the physical properties of the fruit with fresh mass (FM), pulp dry matter content (DMC), and pulp coloration; and (ii) the chemical properties with pulp sugar content and pulp acidity. These indicators were monitored on on-tree fruit, from about 60 days after bloom until full maturity. The same indicators were also monitored on fruit stored in cold storage rooms during ripening. The effects of leaf-to-fruit ratio (manageable by pruning or fruit thinning), maturity stage of fruit at harvest (manageable by harvest date), and storage temperature on the kinetics of quality traits of on-tree and stored fruit were assessed. In addition, a change-point analysis was applied to the sweetness index kinetics (used as a proxy of fruit ripening) to study fruit ripening induction. The leaf-to-fruit ratio mainly influenced fruit growth in terms of FM and pulp DMC, whereas it had less impact on the evolution of fruit chemical properties. The maturity stage of the fruit at harvest was a key factor in determining the potential quality at the ripe stage. Ripening occurs naturally at the mature green stage for on-tree fruit, but ripening at an earlier stage can be induced by harvesting the fruit. During the ripening phase, a low leaf-to-fruit ratio and a cold storage temperature tended to slow down the daily rate of sweetness increase. The use of cold temperatures during storage slowed down starch degradation and sucrose accumulation, while almost stopping the variation in fruit coloration and acidity.

Bitter vetch (Vicia ervilia (L.) Willd) is a promising legume, drought tolerant, mainly used in the Mediterranean area for its grains as a source of proteins in animal feed. However, it is an underused crop cultivated in marginal soils. Ecological, agro-morphological, and bromatological diversity evaluations were conducted to study its reintroduction potential. Seeds of seventeen ecotypes were collected in seventeen farms located in Northern Morocco in 2018. The cultivation was realised during the 2019 and 2020 growing seasons using a randomised complete block design with three replicates. Agro-morphological data were collected at the start of flowering, full flowering, and pod setting phenological stages. Yield component assessment and grain and straw bromatological characterisation were performed at maturity. The results indicated significant variations between ecotypes for almost all parameters and interesting results about yield (1 t ha–1) but lower protein content (22.9% of dry matter) compared to other ecotypes of the Mediterranean region. The estimated genetic parameters could emphasise the possibility of selecting highly productive and nutritive cultivars. However, interannual variations were also detected, making the selection of the ecotypes harder. No significant correlations were observed between agro-morphological and bromatological traits of grains and geographical distances. Multivariate analyses (principal component analysis and heatmap) clustered ecotypes into five groups, where the ecotypes included in the second cluster were the most interesting candidates for developing high-yielding and nutritive varieties. That is why this plant could be considered of interest, especially in these times of climate change.

The productivity of wheat is low on smallholder farms in Rwanda. Although mineral fertiliser use is being promoted as a sustainable intensification (SI) pathway, little is known about the nutrient use efficiency and profitability of various fertiliser inputs in Burera, Musanze and Nyamagabe districts of Rwanda. The objective of this study was to assess the use of combinations of nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), zinc (Zn) and boron (B) in wheat production in terms of nutrients management specifically, crop yield, production risk, input use efficiency and economic returns on smallholder farms. The study was conducted in three wheat-growing regions of Rwanda (i.e., Nyamagabe, Musanze and Burera districts) with contrasting soil conditions. The treatments included combinations of different levels of N (0, 30, 60, 90 and 120 kg ha−1) with P (0, 7.5, 15 and 22.5 kg ha−1) and K (10, 20 and 30 kg ha−1) and the control with no applied nutrients. A diagnostic treatment composed of 90 kg N, 15 kg P, 20 kg K, 10 kg Mg, 2.5 kg Zn and 0.5 kg B ha−1 was also included. Mean grain yield and its variability, rainfall use efficiency (RUE), agronomic use efficiency (AE) of N and P and the value cost ratios (VCRs) were calculated to assess the sustainability of the nutrient rates. Across all sites, wheat grain yield and RUE increased with increase in N rates up to 90 kg N ha−1, beyond which no further increase was observed. The highest wheat yield (5.5 t ha−1) and RUE (6.6 kg ha−1 mm−1) with the lowest production risk (coefficient of variation [CV] = 20%) were recorded in the diagnostic treatment. Although the highest AEN and AEP were recorded at lower N and P levels, the CVs of VCR were high (>64%), indicating higher production risk to wheat farmers. In all cases, an optimum VCR (5.6), with the lowest CV (44.4%), was recorded in the diagnostic treatment. We conclude that application of 90 kg N, 15 kg P, 20 kg K, 10 kg Mg, 2.5 kg Zn and 0.1 kg B can guarantee a more SI of wheat production in Burera, Musanze and Nyamagabe districts of Rwanda.

Readers may be interested to know about the above publication received but not reviewed because of its limited relevance to the majority of readers of Experimental Agriculture.

Preparation of small catchment areas on rainfed valley floor soils in highland Balochistan, Pakistan, is a low-cost method of generating run-off and increasing crop yields within the cropped areas. The effect of different proportions of water catchment area to cropped area were investigated by comparing a control treatment with the entire area planted to the crop (traditional rainfed agriculture); a 1:1 treatment, with one half of the area used for water catchment and one half for planting; and a 2:1 treatment, with two thirds of the area used for water catchment and one third for planting. Results from six seasons of trials using wheat (Triticum aestivum) showed that the 1:1 treatment had 23% higher net benefits than the control, with a 19% reduction in the coefficient of variation. The 2:1 treatment had 29% lower net benefits than the control and reduced the variation in net benefits by 8%. By contrast, four seasons of trials using barley (Hordeum vulgare) showed that the l: l treatment yielded 25% lower net benefits than the control but increased by 4% the variation in net benefits. Treatment 2:1 had 36% lower net benefits than the control and 18% more variation. Even though the gross revenue from wheat under the 1:1 treatment was less than that from the control, the reduction in total costs in the 1:1 treatment resulted in larger net benefits than the control. Water-harvesting in the valley floors is not a net yield-increasing technology. Land suitable for cultivation is limited and the increases in yields in the cropped area resulting from water-harvesting are offset by the opportunity costs of the catchment area. However, wheat grown in a 1:1 ratio of cropped to catchment area can increase farmers' income and decrease its variation. For barley, farmers are better off using their traditional management practice than giving up part of their cropped area to create water catchments.